Vet Path 2007 Summary

Epithelioid Variant of Hemangioma and Hemangiosarcoma in the Dog, Horse, and Cow. Vet Pathol 44:15–24 (2007). Epithelioid hemangiomas, hemangioendotheliomas, and angiosarcomas are well recognized histologic variants of endothelial tumors in humans that in the past have been confused with neoplasms of epithelial or histiocytic origin. Most often reported in the dermis or subcutis.

Myofasciitis in the Domestic Ferret. Vet Pathol 44:25–38 (2007). young ferrets, Gross lesions -atrophy of skeletal muscle; red and white mottling and dilatation of the esophagus; and splenomegaly. Histologically-suppurative to pyogranulomatous mypsitis in the esophagus, heart, limbs, body wall, head, and lumbar regions. Myeloid hyperplasia of spleen and/or bone marrow also is a prominent feature. Ultrastructural lesions include mitochondrial swelling, intracellular edema, disruption of myofibrils and Z bands.

Prevalence and Histopathologic Characteristics of Pancreatitis in Cats. Vet Pathol 44:39–49 (2007). The lesions of CP in cats resemble CP in humans, with fibrosis being more prominent than inflammatory changes. Cystic degeneration gradually increased. A distinct nodular change of zymogen depletion and acinar cell dysplasia not associated with pancreatitis was prominent in 15.6% of the pancreases. Histologically, AP consisted of neutrophilic inflammation associated with interstitial edema and necrosis of mesenteric fat.

CNS Hypomyelination in Rat Terrier Dogs with Congenital Goiter and a Mutation in the Thyroid Peroxidase Gene. Vet Pathol 44:50–56 (2007). Hyperplasia of the follicular epithelium, myelin deficiency, most evident in the corpus callosum. A homozygous nonsense mutation in the thyroid peroxidase gene.

Morphometric Analysis of the Retina from Horses Infected with theBorna Disease Virus. Vet Pathol 44:57–63 (2007). BD was diagnosed by detection of pathognomonic Joest-Degen inclusion bodies (intranuclear) in the postmortem brains. Retinae with strongly altered histologic appearance as well as retinae with only minor changes. BD in horses causes alterations of the retinal histology of a variable degree. A loss of photoreceptors may explain the observed blindness in infected horses.

Experimental Infection of C3H/HeJ Mice with the NY18 Isolate of Anaplasma phagocytophilum. Vet Pathol 44:64–73 (2007). Human granulocytic anaplasmosis (HGA) is caused by Anaplasma phagocytophilum. Gross- Splenomegaly. Microscopic - inflammatory lesions in the lung and liver, hyperplastic lesions on the spleen.

Immunohistochemical Detection of Protein Gene Product 9.5 (PGP 9.5) in Canine Epitheliotropic T-Cell Lymphoma (Mycosis Fungoides). J. A. RAMOS-VARA AND M. A. MILLER. Protein gene product 9.5 (PGP 9.5), a ubiquitin COOH-terminal hydrolase is expressed in a variety of epithelial and mesenchymal tumors (and neural/neuroendocrine). All tumors were confirmed as T-cell epitheliotropic lymphoma

by histopathology and immunohistochemistry for CD3. Eight of 14 cases were positive for PGP 9.5, with reactivity mainly in the cytoplasm and less commonly in the nucleus.

An Immunohistochemical and Polymerase Chain Reaction Evaluation of Feline Plasmacytic Pododermatitis. Vet Pathol 44:80–83 (2007). Mycobacterium bovis. Bartonella spp., Ehrlichia spp., Anaplasma phagocytophilum, Chlamydophila felis, Mycoplasma spp., Toxoplasma gondii, and feline herpesvirus 1 (FHV-1) were negative.

Maxillary Ameloblastic Carcinoma in an Alaskan Malamute. Vet Pathol 44:84–87 (2007). Mass in right maxilla with palisading cells distributed irregularly in cords.

Escherichia coli Septicemia Associated with Lack of Maternally Acquired Immunity in a Bottlenose Dolphin Calf. Vet Pathol 44:88–92 (2007). Lesions included omphalitis, synovitis, and hepatic necrosis associated with the presence of Gram-negative bacilli. A serum gammaglobulin level of 1.5 g/L indicated a lack of maternally acquired immunity.

Solitary Biliary Hamartoma with Cholelithiasis in a Domestic Rabbit(Oryctolagus cuniculus). Vet Pathol 44:92–95 (2007). network of large varying sized cystic structures lined by simple cuboidal to columnar epithelium within an abundant fibrous stroma. Within many of the cyst lumina were varying sized, pale white to greenish hard concretions identified as choleliths and were analyzed and found to be composed of calcium carbonate. (human synonym=von MeyenburgComplexes).

Histologic and Ultrastructural Studies of Juvenile Onset Renal Disease in FourRottweiler Dogs. Vet Pathol 44:96–100 (2007). Cystic dilatation of Bowman’s space, mesangial hypercellularity, and glomerulosclerosis. Three dogs also had glomerular crescents and moderate to severe interstitial fibrosis. Electron microscopy revealed glomerular basement membranes of variable thickness, with extensive splitting or lamellation of the lamina densa. These ultrastructural findings are similar to those found in people and in other breeds of dogs with inherited defects in type IV collagen.

Mesenchymal Hamartoma of the Liver in a Late-Term Equine Fetus. Vet Pathol 44:100–102 (2007). normal hepatic parenchyma had been obliterated, replaced, and expanded by abnormal bile ducts surrounded by abundant, myxoid stroma. Small portions of the liver had bridging septa of fibrosis and proliferations of small-caliber abnormal bile ducts, resembling another congenital biliary abnormality termed congenital hepatic fibrosis.

Severe Granulomatous Lesions in Several Organs from Eustrongylides Larvae in aFree-ranging Dice Snake, Natrix tessellate. Vet Pathol 44:103–105 (2007). nematode larvae surrounded by a capsule, forming a parasitic granuloma with 3 layers: macrophage layer, lymphocyte layer, and fibrous capsule. Differences between newly formed and mature granulomas consisted mainly in the eosinophilic infiltration. subcutaneous connective tissues, on the serosae of the intestines and liver.

Fibrosing Gastrointestinal Leiomyositis as a Cause of Chronic IntestinalPseudo-Obstruction in an 8-Month-Old Dog. Vet Pathol 44:106–109 (2007). both the small and large intestines were distended and fluid-filled. The abdominal cavity contained approximately 500 ml of a brownish clear fluid. Microscopic lesions -intestinal tunica muscularis and muscularis mucosae --extensive-to-diffuse replacement of the smooth muscle by fibrous tissue and infiltration by a moderately dense mononuclear inflammatory infiltrate. A unique finding was the presence of similar microscopic lesions in the tunica muscularis of the urinary bladder and stomach.

Fatal Ulcerative and Hemorrhagic Typhlocolitis in a Pregnant Heifer Associated with Natural Bovine Enterovirus Type-1 Infection. Vet Pathol 44:110–115 (2007). mucosal hemorrhage and ulceration were observed in the spiral colon and cecum. nonenveloped virus.

In vivo Endothelial Cell Infection by Anaplasma marginale. Vet Pathol 44:116–118 (2007). co-localizes with the endothelial cell marker, von Willebrand factor, in tissue sections from an experimentally inoculated calf. The results indicate that A marginale infection includes endothelial cells.

Verminous Encephalitis in a Horse Produced by Nematodes in the Family Protostrongylidae. Vet Pathol 44:119–122 (2007). Parasitic granulomatous eosinophilic inflammation was associated with eggs, larvae, and adult nematodes in the cerebellum. Nematodes had histological characteristics of the superfamily Metastrongyloidea. The presence of dorsal-spined larvae in the CNS was further indicative of infection with a nematode in the family Protostrongylidae. Infections were most compatible with Parelaphostrongylus tenuis but specific diagnosis was not possible.

Disseminated Mycobacterium avium subsp. avium infection in a pet Korean squirreln (Sciuris vulgaris coreae). Vet Pathol 44:123–125 (2007). Grossly, multiple small nodules in the lung, liver, spleen, and skin. necrosis and calcification in an enlarged bronchial lymph node.

Pathology of Natural Infections by H5N1 Highly Pathogenic Avian Influenza Virus in Mute (Cygnus olor) and Whooper (Cygnus cygnus) Swans. Vet Pathol 44:137–143 (2007). multifocal hemorrhagic necrosis in the pancreas, pulmonary congestion and edema, and subepicardial hemorrhages. Major histologic lesions were acute pancreatic necrosis, multifocal necrotizing hepatitis, and lymphoplasmacytic encephalitis with neuronal necrosis. Adrenals displayed consistently scattered cortical and medullary necrosis. In spleen and Peyer’s patches, mild lymphocyte necrosis was present. In the brain, a large number of neurons and glial cells, especially Purkinje cells, showed immunostaining.

Chlamydiae in Free-Ranging and Captive Frogs in Switzerland. Vet Pathol 44:144–150 (2007). Of the frogs collected for the prevalence study, 6 of 238 (2.5%) tested positive. no connection to a mass mortality.

Characterization of a Rat Subcutaneous Malignant Fibrous Histiocytoma and Its Tumor Lines, with Reference to Histiocytic Features. Vet Pathol 44:151–160 (2007). fusiform cells arranged in interlacing bundles with fibrous stroma. Occasional giant cells with bizarre nuclei were observed. positive reaction to vimentin and lysosomal enzyme markers such as acid phosphatase (ACP) and nonspecific esterase (Non-SE).

A Clinicopathological Study of 52 Feline Epulides. Vet Pathol 44:161–169 (2007). Fibromatous (57.7%) , giant cell epulis (28.8%) , acanthomatous (7.7%), ossifying 5.8%). Giant cell epulides presented significant differences in clinical behavior compared with the fibromatous type, including rapid growth, presence of ulcerative changes, and rapid recurrence after surgery. Extensive ulceration and inflammation results in increased osteoclastic activity. The osteoclast-like giant cells are most likely formed from a monocyte/ macrophage-like osteoclast precursor that differentiates into osteoclasts under the influence of mononuclear osteoblast-like stromal cells.

Spontaneous and Experimental Glycoprotein Storage Disease of oats Induced by Ipomoea carnea subsp fistulosa onvolvulaceae). Vet Pathol 44:170–184 (2007). swainsonine-containing and calystegine- containing plant Ipomoea carnea subsp fistulosa. Muscle atrophy. cytoplasmic vacuolation in neurons of the central and the autonomous nervous system, pancreatic acinar cells, hepatocytes, Kupffer cells, follicular epithelial cells of the thyroid gland, and macrophages of the lymphatic tissues. Neuronal necrosis, axonal spheroids formation, and astrogliosis were additionally observed in the brain. inhibition of the lysosomal a-mannosidase by the alkaloid swainsonine.

Pathology and Virus Tissue Distribution of Turkey Origin Reoviruses in Experimentally Infected Turkey Poults. Vet Pathol 44:185–195 (2007). bursal atrophy characterized by lymphoid depletion and increased fibroplasia between the bursal follicles. Both IHC and ISH revealed viral antigen and RNA in the surface epithelial cells of the bursa, in macrophages in the interstitium of the bursa and, to lesser degree, in splenic red pulp macrophages and intestinal epithelial cells. The lymphoid depletion observed in the bursa appears to be the effect of an indirectly induced apoptosis and would most likely result in immune dysfunction in poults infected with TRV.

High-throughput Immunophenotyping of 43 Ferret Lymphomas Using Tissue Microarray Technology. Vet Pathol 44:196–203 (2007). The results of this study confirmed previously published results suggesting specific cross-reactivity of the applied IHC markers (CD3, CD79a, Ki67) with ferret lymphoma tissue. Other IHC markers (CD45Ro, bcl2, bcl10, MUM1, CD30, vimentin) were also expressed in subsets of the included ferret lymphomas. TMA technology was useful for rapid and accurate analysis of protein expression in large archival cohorts of ferret lymphoma cases.

Teratoma of the Umbilical Cord in a Giraffe (Giraffa camelopardalis reticulata). Vet Pathol 44:204–206 (2007). Histologically, the mass contained 3 germinal tissue

components with areas of squamous epithelium, respiratory epithelium, primitive neural tissues, glial tissue, peripheral nerve, adipose tissue, cartilage, and smooth muscle.

Colonic Ganglioneuromatosis in a Horse. Vet Pathol 44:207–210 (2007). fascicles of spindle-shaped cells consistent with Schwann cells, clusters of neurons, supporting enteric glial cells, and thick bands of perineurial collagen. Most of the nodules coincided with the location of the myenteric plexus and extended through the outer layer of the tunica muscularis to the serosal surface. With Immunohistochemistry neurons were positive for neuron specific enolase (NSE) and S-100 and the Schwann cells and enteric glial cells were positive for S-100 and glial fibrillary acidic protein (GFAP).

Three Equine Cases of Mixed Hepatoblastoma with Teratoid Features. Vet Pathol 44:211–214 (2007). sheets and cords of fetal and embryonal epithelial cells that frequently formed sinusoid-like structures. Intermixed with the neoplastic epithelial cells were variable amounts of hemorrhage, necrosis, osteoid, and bone. Immunohistochemically, the epithelial cells stained variably positive for alpha- fetoprotein, frequently positive for vimentin, and occasionally positive for Cytokeratin.

Pulmonary Aspergillosis and Ischemic Distal Limb Necrosis Associated with Enteric Salmonellosis in a Foal. Vet Pathol 44:215–217 (2007). Salmonella typhimurium-disseminated pyogranulomas with intralesional fungal hyphae. The morphologic characteristics of fungal hyphae were consistent with Aspergillus spp., and large numbers of A fumigatus were isolated. Thus, limb lesions are consistent with symmetrical peripheral gangrene, a potential complication of sepsis.

Fatal Streptococcus canis Infections in Intensively Housed Shelter Cats. Vet Pathol 44:218–221 (2007). 1. skin ulceration and chronic respiratory infection that progressed, in some cats, to necrotizing sinusitis and meningitis. 2. progression from necrotizing fasciitis with skin ulceration to toxic shock–like syndrome, sepsis, and death. S canis was the sole pathogen identified in most cases.

Osseous Metaplasia in the Eye of a Dog. Vet Pathol 44:222–224 (2007). Histopathology revealed a diagnosis of bone formation within otherwise normal iris tissue. Non-neoplasitc.

Confocal Laser Scanning Analysis of an Equine Oral Mast Cell Tumor with Atypical Expression of Tyrosine Kinase Receptor C-KIT. Cresyl violet-positive mast cells accompanied by numerous eosinophils. Strong, diffuse, intracytoplasmatic immunohistochemical signal for tryptase and a faint membrane-associated and perinuclear signal for tyrosine kinase receptor KIT. Confocal laser scanning microscopy confirmed an aberrant spatial colocalization of KIT in the Golgi apparatus, which may be the result of a defective protein processing within the tumor cells.

Round Cell Variant of Myxoid Liposarcoma in a Japanese Macaque (Macaca fuscata). Vet Pathol 44:229–232 (2007). Reddish tan to white nodules, ranging from 0.5 to 1 cm in diameter, were noted throughout the omentum and retroperitoneum.

Round to polyhedral cells, which had round, often eccentric nuclei and abundant eosinophilic granular and microvacuolated cytoplasm; Oil red O staining demonstrated large numbers of lipid droplets in the cytoplasm.

Amyloid-Producing Odontogenic Tumor and Its ImmunohistochemicalCharacterization in a Shih Tzu Dog. Vet Pathol 44:233–236 (2007). nests, islands, and strands of proliferating odontogenic and squamous epithelial cells, intermingled in close association with large numbers of irregular extracellular deposits of amyloid and amorphous calcified substance.

Two Independent Cases of Spontaneously Occurring Branchioblastomas in Koi Carp (Cyprinus carpio). well-demarcated, pale red nodular masses located atthe left first branchial arch and the right pseudobranch, respectively. Histologically, the neoplasias were composed of blast-like cells that differentiated into cartilage and branchial lamellae embedded in abundant fibrous connective tissue. Based on these findings, a branchioblastoma was diagnosed.

Synovial Hemangioma in the Stifle Joint of a Dog. Vet Pathol 44:240–243 (2007). vascular channels that were lined by well-differentiated endothelial cells and separated by fibrous septa. Distension of some channels resulted in endothelial disruption, thrombosis, hemorrhage, necrosis, and focal spindle-cell proliferation.

A Mixed Epithelial and Stromal Tumor of the Kidney in a Ringtail Lemur (Lemur catta). Vet Pathol 44:243–246 (2007). The mesenchymal cells were arranged in fascicles around cysts lined by a well-differentiated epithelium.

Equine Osteosarcoma: A Series of 8 Cases. Vet Pathol 44:247–249 (2007). mandible of young horses.. fibroblastic osteosarcoma with fewer osteoblastic type tumors.

Hermaphroditism in 3 Chimeric Mice. Vet Pathol 44:249–252 (2007). Histologically, mice Nos. 1 and 3 were true hermaphrodites with unilateral ovotestes, while mouse No. 2 was a pseudohermaphrodite with ovarian tissue only.

Cranial Nerve Hamartoma in a Dog. firm, white nodules across the petrosal crest of the skull. Microscopically, the nodules were composed of normal myelinated nerve fibers within a mucinous stroma.

Distribution of Lesions and Antigen of Highly Pathogenic Avian Influenza Virus A/Swan/Germany/R65/06 (H5N1) in Domestic Cats after Presumptive Infection by Wild Birds. Vet Pathol 44:261–268 (2007). Histologically, the main findings associated with influenza in all cats were bronchointerstitial pneumonia and marked random hepatic necrosis. In addition, all animals displayed lymphoid necrosis in the spleen and Peyer’s patches and necrosis of the adrenal cortex. Immunohistochemically, nucleoprotein of HPAIV was present intralesionally in the lungs, liver, adrenal glands, and lymphoid tissues. Incidental finding- granulomatous pneumonia caused by Aelurostrongylus sp.

Infection of Internal Umbilical Remnant in Foals by Clostridium sordellii. Vet Pathol 44:269–275 (2007). All foals had acute peritonitis, and the internal umbilical remnant was thickened by edema, hemorrhage, and fibrosis. A moderate amount of serosanguinous fluid with fibrin strands was present in the pericardial sac and pleural cavity. Histopathologically, the urachus and umbilical arterial walls were thickened by edema and exhibited hemorrhage, fibrin, and leukocytic infiltration. Gram-positive bacterial rods were observed in subepithelial areas of the urachus, the adventicia of umbilical arteries, and interstitium of the internal umbilical remnant. In foals, the most important causes of omphalitis are Escherichia coli and Streptococcus zooepidemicus.

Uveal Spindle Cell Tumor of Blue-Eyed Dogs: An Immunohistochemical Study. Vet Pathol 44:276–284 (2007). anti-UVssDNA, and TERT. Electron microscopy revealed intermittent basal laminae between cells. These tumors are morphologically and immunohistochemically most consistent with schwannoma. All tumors were negative for SMA, desmin, Melan A, and MITF-1. Tumors were variably positive for PGP 9.5, laminin, gadd45, p53, PCNA, anti-UVssDNA.

Experimental Transmission and Induction of Ranaviral Disease in Western Ornate Box Turtles (Terrapene ornata ornata) and Red-Eared Sliders (Trachemys scripta elegans). Vet Pathol 44:285–297 (2007). Consistent histologic lesions were observed only in IM-inoculated turtles and included fibrinoid vasculitis centered on splenic ellipsoids, multifocal hepatic necrosis, and multicentric fibrin thrombi in a variety of locations, including hepatic sinusoids, glomerular capillary loops, and pulmonary capillaries. Virions compatible with Ranavirus (Iridoviridae) were observed within necrotic cells of the spleen of 1 IM-inoculated turtle using transmission electron microscopy. This study fulfills Koch’s postulates, confirming a causal relationship between BSTRV and the clinical and histologic changes in chelonians infected with this virus.

Cellular Proliferation in Canine Cutaneous Mast Cell Tumors: Associations with c-KIT and Its Role in Prognostication. Vet Pathol 44:298–308 (2007). In this study, increased Ki67 and AgNOR counts were both associated with significantly decreased survival. Additionally, the results of this study show that MCTs with aberrant KIT protein localization or internal tandem duplication c- KIT mutations are associated with increased cellular proliferation, further suggesting a role for c-KIT in the progression of canine MCTs.

Uterine Infarctions in Cynomolgus Monkeys (Macaca fascicularis). Vet Pathol 44:309–313 (2007). uterine infarction is an uncommon finding in cynomolgus monkeys and may occur secondary to a severe systemic illness, predisposing to DIC.

Conidiobolomycosis in Sheep in Brazil. Vet Pathol 44:314–319 (2007). Mucohemorrhagic nasal discharge, and cranium-facial asymmetry from exophthalmos of 1 eye, generally with increased volume of the eyeball, keratitis, and corneal ulceration.

Friable masses were observed in the posterior region of the nasal cavity, often destroying the ethmoturbinate bones. Frequently, the lesions invaded the nasal sinuses, cribiform plate, orbit, and brain. In all lesions, negatively stained structures representing hyphae were surrounded by Splendore-Hoeppli material. Coagulative necrosis, thrombosis, and vasculitis were also observed. Grocott methenamine silver stain showed 8–30-mm-thick hyphae, rarely septate or ramified, irregular in shape, and with black contoured wall, sometimes with bulbous dilatation in the extremities.

Histologic Features of Mammary Carcinomas in Zoo Felids Treated with Melengestrol Acetate (MGA) Contraceptives. Vet Pathol 44:320–326 (2007). These results indicate that mammary carcinomas in zoo felids are high grade with a predominant tubulopapillary pattern and aggressive behavior. Five of 17 carcinomas expressed progesterone receptors, and 1 of 17 expressed estrogen receptors. Although more zoo felids with cancer had been exposed to MGA in this study, mammary carcinomas were similar in appearance and behavior in untreated and MGA-treated zoo felids.

Epizootic of Tularemia in an Outdoor Housed Group of Cynomolgus Monkeys (Macaca fascicularis). Vet Pathol 44:327–334 (2007). Pathologic findings were similar in all monkeys that died and resembled the clinical picture of the human disease, including an ulceroglandular syndrome with local lymphadenopathy, gingivostomatitis, and systemic spread, with manifestations such as subacute necrotizing hepatitis, granulomatous splenitis, and Pneumonia.

Mitotic Index Is Predictive for Survival for Canine Cutaneous Mast Cell Tumors. Vet Pathol 44:335–341 (2007). For grade II tumors with anMI #5, the median survival time (MST) was 70 months, compared with 5 months for those with an MI .5 (P , .001).

Chondrodysplastic Calves in Northeast Victoria. Vet Pathol 44:342–354 (2007). Calves showed variable disproportionate dwarfism without arthrogryposis. Long bones were shortened and showed axial rotation. Articular surfaces were distorted with misshapen weight-bearing surfaces associated with variable thickness of articular cartilage. Physes were distorted and variable in thickness with occasional foci of complete closure. The major histologic abnormality in the physes was disorderly development of the zones of cartilage hypertrophy, with reduced number and irregular arrangement of hypertrophic chondrocytes; similar less severe changes were present in the zones of cartilage proliferation. Histochemical staining of the cartilage matrix was variable in intensity, and there was evidence of abnormal resorption of cartilage matrix at the level of the primary spongiosa. Osteoid formation and subsequent bone remodeling seemed unaffected, and diaphyseal cortical bone appeared normal at the gross and light microscopic level. No infectious agents were identified, and other known causes for chondrodysplasia in calves were excluded. The most likely cause for the syndrome was considered to be congenital manganese deficiency.

Diagnoses and Clinical Outcomes Associated with Surgically Amputated Canine Digits Submitted to Multiple Veterinary Diagnostic Laboratories. Vet Pathol 44:355–361 (2007). Squamous cell carcinoma was the most commonly identified tumor (n 5 109, 36.3%), and 11 of 42 dogs for which clinical follow-up information was available developed metastatic disease. Squamous cell carcinoma of the digit appears to have a greater metastatic potential than that occurring elsewhere in the body. Other common diagnoses included melanoma (n 5 52, 17.3%), soft-tissue sarcoma (n 5 29, 9.7%), and mast cell tumor (n 5 20, 6.7%). Melanomas were associated with poor prognoses, with a median survival time of 365 days.

Diagnoses and Clinical Outcomes Associated with Surgically Amputated Feline Digits Submitted to Multiple Veterinary Diagnostic Laboratories. Vet Pathol 44:362–365 (2007). Squamous cell carcinoma was the most commonly identified malignant tumor (n 5 15; 23.8%) and was associated with a median survival time of 73 days. Other diagnoses included fibrosarcoma (n 5 14; 22.2%); adenocarcinoma, likely metastases of a primary pulmonary neoplasm (n 5 13; 20.6%); osteosarcoma (n 5 5; 7.9%); mast cell tumor (n 5 4; 6.3%); hemangiosarcoma (n 5 5; 7.9%); malignant fibrous histiocytoma (n 5 2; 3.2%); giant cell tumor of bone (n 5 2; 3.2%); and hemangioma (n 5 2; 3.2%). Giant cell tumor of bone has not been previously described in the digits of cats.

Distribution and Activation of T-lymphocyte Subsets in Tuberculous BovineLymph-node Granulomas*. Vet Pathol 44:366–372 (2007). In the majority of stage I/II lesions, CD8+ and CD25+ cells were predominantly found in the lymphocytic outer region of the granuloma, suggesting a possible role for activated CD8+ cells in the initial attempt to restrain the granuloma growth. CD4+ T cells appeared equally distributed in the lymphocytic mantle and in the internal areas of the granulomas. WC1+ cells appeared interspersed among the macrophages. We speculated that this could indicate a role for these 2 subsets in the maintenance and the maturation of the granuloma. In stage III/IV lesions, all of the T-cell subsets investigated appeared interspersed among the mononuclear component of the granulomas. In general terms, there was a higher density of CD8+ cells compared with CD4+ cells.

Estrogen Receptors a and b and Progesterone Receptors in Normal Bovine Ovarian Follicles and Cystic Ovarian Disease. Vet Pathol 44:373–378 (2007). The follicular cysts of animals with COD presented a significantly higher expression of estrogen receptor a in all follicular layers than secondary, tertiary, and atretic follicles in both groups (P , .05). Differences did not exist between the 2 groups with regard to the progesterone receptor. Ovaries of animals with COD exhibited altered estrogen receptors expression compared with that in normal animals.

Endometrial Stromal Sarcoma with Smooth Muscle and Glandular Differentiation of the Feline Uterus. Vet Pathol 44:379–382 (2007). The tumor showed a proliferation of both endometrial stromal and smooth muscle cells accompanied by prominent vasculature. There were well-differentiated endometrial glands, and tubuli made up a monolayer of eosinophilic cuboidal epithelium. Immunohistochemically, the spindle-

shaped cells and half of the stromal-like cells reacted to caldesmon and desmin antibodies. The neoplastic epithelium expressed AE1/AE3 cytokeratin.

Kernicterus (bilirubin toxicity) in an Adult Dog. Vet Pathol 44:383–385 (2007). Necropsy findings included profound icterus and red and yellow mottling of the liver. Yellow discoloration of the thalamic and subthalamic nuclei was detected on subgross examination of the formalin-fixed brain. Histologic examination of the brain revealed neuronal necrosis within the discolored nuclei, necrosis of Purkinje cells, and Alzheimer type II astrocytes in the cerebrocortical gray matter and in the nuclei, with gross discoloration. Histologic examination of the liver revealed extensive necrosis in a periacinar-to-bridging pattern and often extending to portal triads.

Ovarian and Intestinal Angiomatosis in a Horse. Vet Pathol 44:386–388 (2007). Raised nodules on the serosal surface of the small intestine and the right and left ovaries were composed of numerous, variably sized, redundant vascular profiles filled with red blood cells and fibrin thrombi. Based on the presence of multiple nodules composed of benign vascular channels scattered within the small intestine and ovary, a diagnosis of angiomatosis is proposed.

Immunoglobulin Crystals in Reactive Plasma Cells in a Dog. Vet Pathol 44:389–391 (2007). Intracellular crystalline deposits of immunoglobulin are occasionally seen in human B-cell lymphoproliferative disorders such as multiple myeloma, chronic lymphocytic leukemia, and various forms of lymphoma. Theses were in a chronic inflammatory lesion. Microscopically, the intracellular, nonbirefringent eosinophilic crystals were square to rectangular, 2–20 mm long, and caused nuclear displacement to the periphery. The crystal-containing cells, as well as some of the crystals themselves, were positive for lambda light chain.

Tail Root Osteosarcoma in a Chipmunk (Tamias sibiricus). Vet Pathol 44:392–394 (2007). Histologically, the excised mass showed proliferation of spindle-to-polyhedral cells and abundant multinucleated giant cells, with the production of neoplastic osteoid. Immunohistochemically, neoplastic cells were positive for vimentin and weakly positive for osteocalcin. Osteoid was also positive for osteocalcin. This tumor was diagnosed as a giant cell–type osteosarcoma.

Interstitial Cell Tumor and Sertoli Cell Tumor in the Testis of a Cat. Vet Pathol 44:394–397 (2007). The presence of penile papillae implied testosterone production. Testes were not palpable, but the left testis was found in the scrotum by surgical exploration and was mostly replaced by the 2 tumors. The interstitial cell tumor, but not the Sertoli cell tumor, was immunohistochemically positive for Melan-A, consistent with steroid production.

Multiple Masses in a Horse’s Tongue Resulting from an Atypical Perineurial Cell Proliferative Disorder. Vet Pathol 44:398–402 (2007). Microscopically, the bases for these

masses were slender, fusiform, mesenchymal cells that formed compact whorls around myelinated and unmyelinated nerves. These cells were labeled by antibodies directed against vimentin but not by S-100. Ultrastructurally, multiple, concentrically arranged, long, slender cell processes, with discontinuous external laminae and many pinocytotic vesicles, helped to accurately phenotype the proliferative element .

Primary Cardiac Fibrosarcoma with Pulmonary Metastasis in a Labrador Retriever. Vet Pathol 44:403–407 (2007). Large mass inside the pericardial sac associated with the left ventricle. At necropsy, the dog had marked ascites, mild hydrothorax, marked hydropericardium, and an 11.0 3 7.0 3 6.0 cm, tan and red, firm, well-demarcated mass attached to the left ventricular free wall. The mass was diagnosed as a fibrosarcoma based on the morphologic appearance and supportive immunohistochemical staining.

Atrioventricular Valvular Angiectasis in Sprague-Dawley Rats. Vet Pathol 44:407–410 (2007). The angiectasis was observed predominately on the septal cusp of the right AV valve and located near the AV ostium in 57 of 62 animals. The angiectases were single or multiple, ranging from 40 to 300 mm in diameter and were characterized by light microscopy as bloodfilled dilatations lined by endothelium..

Fibroepithelial Hamartoma in a Domestic Pig. Vet Pathol 44:411–413 (2007). Histologic examination revealed a moderate orthokeratotic hyperkeratosis with variable degrees of epithelial proliferation. The main body of the dysplasia consisted of collagenous fibers. In addition, some proliferating small blood vessels as well as focally gathered dilated apocrine glands were evident.

Poorly Differentiated Rectal Carcinoid in a Cow. Vet Pathol 44:414–417 (2007). A carcinoid tumor was found as a solitary soft mass in the wall of the rectum adjacent to the anorectal junction in an adult Holstein cow. It consisted of a compact arrangement of a great number of large polygonal cells and a small number of small dark cells, some of which showed argyrophilia (Grimelius positive). Immunohistochemically, both types of tumor cells were positive for vimentin, keratin, and S- 100 protein and weakly positive for neuron-specific enolase (NSE), whereas they were negative for some endocrine markers such as chromogranin A, insulin, glucagon, somatostatin, serotonin, adrenocorticotropic hormone, and calcitonin. Electron microscopy revealed membrane-bound secretory granules in the cytoplasm of some small dark cells. In such a poorly differentiated carcinoid, the morphologic characteristics of the small dark cells were strong evidence for the diagnosis.

Hermaphroditism in a Sprague-Dawley Rat. Vet Pathol 44:418–420 (2007). A spontaneous case of unilateral true hermaphroditism was observed during the routine necropsy of a 9-week-old presumed female Sprague-Dawley rat on a repeat-dose toxicity study. There were no drug-related effects observed. True hermaphroditism is rare in rats, and despite the large numbers of rats examined annually, few cases are reported in the literature.

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Expression of Monocarboxylate Transporter 1 in Oral and Ocular Canine Melanocytic Tumors. Vet Pathol 44:449–457 (2007). Monocarboxylate transporter 1 (MCT1) is a major proton transporter in mammalian cells that transports monocarboxylates, such as lactate and pyruvate, together with a proton across the plasma membrane. Increased MCT1 expression in oral melanomas compared with ocular melanocytic tumors may reflect the very different biology between these tumors in dogs. These results are the first to document canine MCT1 expression in canine tumors and suggest that increased MCT1 expression may provide a potential therapeutic target for oral melanoma.

Auricular Chondritis Caused by Metal Ear Tagging in C57BL/6 Mice. Vet Pathol 44:458–466 (2007). Histopathologically, there were observed severe chondritis with extensive granulomatous inflammation, newly formed cartilage nodules, and osseous metaplasia accompanied by cellular infiltrates, such as CD4 T lymphocyte, macrophages, neutrophils, and mast cells, and expression of Th1 cytokines, such as interferon-gamma, tumor necrosis factor-alpha, and interleukin-2 in the tagged ear. Based on these results, we concluded that the release of copper and iron ions from the metal ear tags played a major role in the onset of auricular chondritis. Subsequent cellular interactions, such as CD4 T cells, macrophages, fibroblasts, and mast cells, mediated by cytokines, such as tumor necrosis factoralpha and interferon-gamma, caused an autoimmune response that may have led to the progression of auricular chondritis as an autoimmune disease.

Inactivation of the p16 Cyclin-Dependent Kinase Inhibitor in High-Grade Canine Non-Hodgkin’s T-Cell Lymphoma. Vet Pathol 44:467–478 (2007). p16 deletion or inactivation occurs almost exclusively in high-grade T-cell NHL; however, alternative pathways can generate functional phenotypes of Rb eficiency in low-grade T-cell NHL and in high-grade B-cell NHL.

Natural Peste des Petits Ruminants Virus Infection: Novel Pathologic Findings Resembling Other Morbillivirus Infections. Vet Pathol 44:479–486 (2007). Pathologic findings included erosiveulcerative stomatitis, fibrino-necrotic tracheitis, bronchointerstitial pneumonia, multifocal coagulation necroses in the liver, and severe lymphocytolysis in lymphoid tissues. Syncytial cells were conspicuous, especially in the oral mucosa, pulmonary alveoli, liver, and lymphoid tissues. these previously unreported pathologic findings in natural peste des petits ruminants virus infection establish a basis for resemblance to other morbillivirus infections, such as canine distemper and distemper of sea mammals.

Susceptibility of Cattle to First-passage Intracerebral Inoculation with Chronic Wasting Disease Agent from White-tailed Deer. Vet Pathol 44:487–493 (2007). Although spongiform encephalopathy (SE) was not observed, abnormal prion protein (PrPd) was detected by immunohistochemistry (IHC) and Western blot (WB) in central nervous system tissues. The absence of SE with presence of PrPd has also been observed when other TSE agents (scrapie and CWDmd) were similarly inoculated into cattle.

Effects of Autologous Stem Cells on Immunohistochemical Patterns and Gene Expression of Metalloproteinases and Their Tissue Inhibitors in Doxorubicin Cardiomyopathy in a Rabbit Model. Vet Pathol 44:494–503 (2007). In conclusion, chronic doxorubicin cardiomyopathy was characterized by increased MMP and decreased TIMP-3 expression. MSCs injection into the LV resulted in marked differences of collagen content and MMP/TIMP expression in the whole heart. After MSC injection, MMP-1, MMP-2, and TIMP-3 expression was higher.

Orbital (Retrobulbar) Meningioma in a Simmental Cow. Vet Pathol 44:504–507 (2007). Microscopically, a poorly differentiated neoplasm was observed. The immunohistochemical panel included cytokeratins, vimentin, epithelial membrane antigen, Factor VIII, CD34, Mart-1, Melan A, smooth muscle actin, desmin, chromogranin, neuron-specific enolase, S-100 protein, and MIB-1. The neoplasm was negative for all of them, with the exception of vimentin and S-100 protein.

Simultaneous Canine Distemper Virus, Canine Adenovirus Type 2, and Mycoplasma Cynos Infection in a Dog with Pneumonia. Vet Pathol 44:508–512 (2007). Pathologic examination revealed a fibrinous necrotizing pneumonia with large amphophilic intranuclear and acidophilic intracytoplasmatic inclusion bodies in different lung cells. Immunohistochemically, CDV antigen was present in lung and many other organs. In situ hybridization for detection of CAV nucleic acid showed positive signals in the lung only. Polymerase chain reaction of lung tissue and consecutive sequencing of the amplification product identified CAV type 2. Bacteriologic examination of lung tissue yielded large amounts of M cynos. The bacteria seem to have been responsible for a strong necrotizing component of the pneumonia, as they were predominantly localized in such areas.

Testicular Interstitial Cell Tumor and Gynecomastia in a Rabbit. Vet Pathol 44:513–517 (2007). Neoplastic interstitial cells exhibited diffuse, granular cytoplasmic staining with Melan A. Multiple subcutaneous masses in the caudal abdomen were associated with enlarged nipples and consisted of hyperplastic mammary gland tissue with proliferation of ducts and alveoli, marked lobule formation, and pseudolactational hyperplasia. Many epithelial cells lining the hyperplastic ducts and alveoli exhibited intense nuclear expression of progesterone receptor antigen, whereas myoepithelial cells showed strong nuclear staining for p63 antigen.

Genitourinary Rhabdomyosarcoma with Systemic Metastasis in a Young Dog. Vet Pathol 44:518–520 (2007). the uterine wall was thickened with poorly defined neoplastic infiltrates. The urinary bladder was markedly thickened due to botryoid nodules exhibiting exophytic growth into the lumen. Metastases to lung, liver, kidney, and abdominal and thoracic lymph nodes were also noted. Microscopically, the genital tract and retroperitoneal masses were consistent with the alveolar subtype of rhabdomysarcoma, while the urinary bladder mass had characteristics of the embryonal subtype. Immunohistochemically, the neoplastic cells in all these tissue sites were intensely positive for desmin, sacromeric actin, and vimentin, while they were uniformly

negative for cytokeratin and smooth muscle actin. Phosphotungstic acid hematoxylin stain revealed cross-striations in the cytoplasm of scattered neoplastic cells.

Characterization of a Population of Unique Granular Lymphocytes in a Bitch Deciduoma, Using a Panel of Histo- and Immunohistochemical Markers. Vet Pathol 44:521–524 (2007). Discrete swellings were found in the uterine horns, with the macroscopic appearance of normal early pregnancy. At histologic examination, the endometrium, devoid of any conceptus and chorion, showed a marked proliferation, on the basis of which a diagnosis of deciduoma was made. Our data indicate that the peculiar lymphocyte population observed in the bitch deciduoma shows similarities with the granulated decidual cells, until now described only in primates and rodents (uNK cells).

Mammary Carcinoma with Sebaceous Differentiation in a Dog. Vet Pathol 44:525–527 (2007). Microscopically, the tumors were composed of two distinctive neoplastic components, intraductal papillary adenocarcinoma and sebaceous carcinoma. The regions of sebaceous tumor were clumped separately, contained well-developed sebaceous cells and keratinized epithelial cells, and were surrounded by few to several layers of basaloid cells. The cells with abundant foamy cytoplasm that resembled sebaceous cells were also found within the intraductal papillary-like nests of mammary carcinoma, providing evidence of sebaceous metaplasia.

Intramedullary Cavernous Malformation of the Spinal Cord in Two Dogs. Vet Pathol 44:528–532 (2007). Extensive intraparenchymal hemorrhage was found on gross postmortem examination in both dogs, and a distinct lobulated intramedullary mass was evident in the second dog. Microscopically, both lesions were composed of dilated, thin-walled vascular channels with little-to-no intervening neural parenchyma. Both dogs had evidence of channel thrombosis along with perilesional hemorrhage and hemosiderin accumulation.

Dental Benign Cementomas in Three Horses. Vet Pathol 44:533–536 (2007). multiple bony enlargements of the upper and lower jaw extending into the oral cavity. Histopathologically, the tumors consisted of excessive deposition of cementum-like tissue. Cells, resembling cementoblasts, lined irregularly shaped lacunae, which were present in the tumor tissue, and showed minimal cellular pleomorphism.Mitotic figures were not present.

Canine Adenovirus Type 1 Infection of a Eurasian River Otter (Lutra lutra). Vet Pathol 44:536–539 (2007). The liver was found to be swollen and friable Microscopically, there was multifocal hepatic necrosis. with large basophilic intranuclear inclusions. Transmission electron microscopy revealed characteristic hexagonal virus particles sized approximately 70 nm in diameter in the nuclei of the hepatocytes.

Lenticular Invasion by a Ciliary Body Adenocarcinoma in a Dog. Vet Pathol 44:540–542 (2007). Histologic evaluation of the enucleated eye revealed a ciliary body adenocarcinoma with lens invasion. Where the tumor encroached on the lens, the lens capsule was absent and there was scrolling of the broken ends of the capsule.

Mycobacterium fortuitum Pneumonia in a Cat and the Role of Lipid in the Pathogenesis of Atypical Mycobacterial Infections. Vet Pathol 44:543–546 (2007). Mycobacterium fortuitum is a nontuberculous, and nonlepromatous mycobacterium that can cause infections in animals and humans. In dogs and cats, it is one of the most common agents of ulcerative dermatitides and panniculitides caused by atypical mycobacteria. IN this case the pneumonia resembled lipoid pneumonia in humans. We discuss the role of lipids in the pathogenesis of mycobacterioses and suggest an association between atypical mycobacteria and lipid-rich environments.

Cholesterol Granuloma Associated with Otitis Media and Destruction of the Tympanic Bulla in a Dog. Vet Pathol 44:547–549 (2007). The necessary factors for the development of CG in the middle ear and other normally aerated bony cavities are thought to be hemorrhage, interference with drainage, and obstruction of ventilation. Possible causes of the initial hemorrhage include mucosal inflammation, trauma, and pressure changes within the air cells. Cholesterol, originating from erythrocyte membranes and possibly mucosa or transudate, precipitates forming crystals which, stimulate a granulomatous reaction and the development of CG.

Canine Hyperplastic Intraepidermal Pustular and Suprabasal Acantholytic Dermatosis with Features of Human Pemphigus Vegetans. Vet Pathol 44:550–555 (2007). Pemphigus vegetans is a rare autoimmune blistering acantholytic dermatosis of humans that combines unusually hyperplastic and verrucous pustular skin lesions and mucosal erosions. circulating autoantibodies against canine desmoglein-1 were solely identified. This antigen target is different from that of the human disease in which antidesmoglein-3 autoantibodies are detected most commonly.

Pathology of Mucopolysaccharidosis IIIA in Huntaway Dogs. Vet Pathol 44:569–578 (2007). By histology, there were variably stained storage cytosomes within neurons, including many that stained for gangliosides. On ultrastructure examination, these cytosomes contained either moderately dense granular material, tentatively interpreted as precipitated glycosaminoglycan; a variety of multilaminar bodies, interpreted as being associated with secondary accumulation of gangliosides; or a mixture of both types

Cutaneous Neoplasms in Pet Rabbits: A Retrospective Study. Vet Pathol 44:579–588 (2007). The most common diagnoses were trichoblastoma, collagenous hamartoma, and Shope fibroma. Viral-induced tumors were Shope fibroma (19) and Shope papilloma (2). Common nonviral epithelial tumors included trichoblastoma (59), squamous cell carcinoma (5), squamous papilloma (4), trichoepithelioma (3), and apocrine carcinoma (3). Common mesenchymal tumors were lipoma (10), liposarcoma (3), myxosarcoma (9), malignant peripheral nerve sheath tumor (8), fibrosarcoma (7), and leiomyosarcoma (4).

Myocarditis Associated with Foot-and-Mouth Disease Virus Type O in Lambs. Vet Pathol 44:589–599 (2007). Inflammatory infiltration, hyaline degeneration, and necrosis of sheets of myocytes were observed. The cellular infiltrates were mononuclear cells, including many lymphocytes, macrophages, a few plasma cells, and neutrophils. Major

histocompatibility complex Class II+ dendritic and mononuclear cells, cd T cells, CD172A+ and CD14+ macrophages and monocytes, and IgM+ B cells were detected mainly in the infected hearts. Inducible nitric oxide synthetase (iNOS) was seen mostly in areas of inflammation infiltrated by large numbers of cells. These findings suggest that the iNOS expressed by inflammatory cells in lesions may have a deleterious effect on cardiac myocytes in these lesions.

Cellular Characterization of Multidrug Resistance P-glycoprotein, Alpha Fetoprotein, and Neovascular Endothelium-Associated Antigens in Canine Hepatocellular Carcinoma and Cirrhotic Liver. Vet Pathol 44:600–606 (2007). P-gp was expressed at higher levels in HCC than in cirrhotic livers, and was most commonly localized in biliary canaliculi and small ductuli. AFP was localized mainly in the cytoplasm in HCC and in. CD31 was expressed strongly in the portal area and parenchyma in HCC, but it was rarely observed in the parenchyma in cirrhosis. CD34 expression could not be detected in both HCC and cirrhosis.

The Spectrum of Canine Cutaneous Perivascular Wall Tumors: Morphologic, Phenotypic and Clinical Characterization. Vet Pathol 44:607–620 (2007). Perivascular wall tumors (PWTs) are defined as neoplasms deriving from mural cells of blood vessels, excluding the endothelial lining. The spectrum of human cutaneous PWT includes glomus tumor, hemangiopericytoma (HEP), myopericytoma, angioleiomyoma/sarcoma, angiomyofibroblastoma, and angiofibroma. Diagnosis was established on the basis of vascular growth patterns (staghorn, placentoid, perivascular whorling, bundles from media) and immunohistology, including 7 smooth muscle markers and the cell membrane ganglioside of unknown origin recognized by the antibody 3G5 (CMG-3G5). HEP is a diagnosis of exclusion.

Porcine Circovirus Type 2-Associated Cerebellar Vasculitis in Postweaning Multisystemic Wasting Syndrome (PMWS)-Affected Pigs. Vet Pathol 44:621–634 (2007). Acute hemorrhages and edema of cerebellar meninges and parenchyma due to a necrotizing vasculitis resulted in degeneration and necrosis of the gray and white matter. Few to numerous PCV2 DNA and antigenbearing endothelial cells were detected. Detection of caspase 3 activity and DNA strand breaks showed numerous apoptotic endothelial cells in the vascular lesions observed. Lesions in PDNS are characterized primarily by a cutaneous and subcutaneous necrotizing vasculitis and glomerulonephritis and are likely mediated by immune complex deposition.

Pathologic Findings of Highly Pathogenic Avian Influenza Virus /Duck/Vietnam/12/05 (H5N1) in Experimentally Infected Pekin Ducks, Based on Immunohistochemistry and In Situ Hybridization. Vet Pathol 44:635–642 (2007). Clinical signs - conjunctivitis and slight depression, severe neurologic signs consisting of torticollis, incoordination, tremors, and seizures. Gross lesions- hemorrhages in the duodenum, ceca, proventriculus, ventriculus, trachea, pancreas, and brain. Histologic lesions, as well as immunohistochemistry positivity, were recorded in the pancreas and brain.

Distribution and Cellular Heterogeneity of Bovine Viral Diarrhea Viral Antigen Expression in the Brain of Persistently Infected Calves: A New Perspective. Vet Pathol 44:643–654 (2007). BVDV antigen was detected in the brains of all persistently infected calves. A variety of cell types was infected, including neurons, astrocytes, oligodendroglia, blood vessel-associated cells (pericytes, perivascular macrophages, smooth muscle cells), and cells in the leptomeninges (blood vessel–associated cells). Conclusive demonstration of viral antigen in vascular endothelial cells was elusive. Viral antigen staining was most consistent and intense in thalamic nuclei, most notably in dorsal and medial nuclear groups, followed by the hippocampus, entorhinal cortex, basal nuclei, and piriform cortex.

Intra-nasal Inoculation of American Bison (Bison bison) with Ovine Herpesvirus-2 (OvHV-2) Reliably Reproduces Malignant Catarrhal Fever. Vet Pathol 44:655–662 (2007). This is the first successful reproduction of MCF in bison using a nasal route of exposure. Experimentally challenged bison are more susceptible to MCF, compared with experimentally challenged domestic cattle in a previous experiment.

Ultrastructural Examination of the Host Cellular Response in the Gills of Atlantic Salmon, Salmo salar, with Amoebic Gill Disease. Vet Pathol 44:663–671 (2007). Amoebae were found either on the surface epithelium or with pseudopodia extending deeply into invaginations of epithelial cells. The amoebae had various densities along the plasma membrane and contained electron-dense deposits within their cytoplasm. Surface epithelial cells sloughed from the gills and had features consistent with apoptosis. Affected areas of gills had fusion of secondary lamellae with interlamellar spaces occupied by mitotic epithelial cells and eosinophils. Eosinophils contained abundant fusiform-shaped granules that measured approximately 1 mm long and 360 nm wide. The granule consisted of an electron-dense matrix with a central inclusion that was less electron-dense, consisting of particulate and fibrillar material.

Metastatic Iridociliary Adenocarcinoma in a Labrador Retriever. Vet Pathol 44:672–676 (2007). Histopathologic evaluation of the globe revealed extensive invasion of the uvea and sclera by a pleomorphic cell population that formed disorganized cords and exhibited PAS-positive basement membrane material. Necropsy revealed a morphologically similar tumor in the ipsilateral orbit and lung. On immunohistochemical examination, the intraocular tumor stained diffusely immunopositive for vimentin, S-100, and neuron-specific enolase and multifocally, sparsely immunopositive for cytokeratinAE1/AE3.

Immunohistochemical Characterization and Evaluation of Prognostic Factors in Canine Oral Melanomas with Osteocartilaginous Differentiation. Vet Pathol 44:676–682 (2007). oral melamonas with osteocartilaginous differentiation have a clinical course similar to that of other melanomas in the oral cavity. Analysis of the mitotic index and the expression of proliferation marker Ki-67 could be useful tools for predicting the biological behavior of these neoplasms.

Cutaneous Toxoplasmosis in a Female Japanese Cat. Vet Pathol 44:683–687 (2007). necrotizing granulomatous panniculitis, vasculitis, and mastitis, and contained free and clustered protozoal organisms. The organism was present in the cytoplasm of macrophages, fibroblasts, endothelial cells, and mammarygland epithelia. The organism was positive for anti-Toxoplasma gondii and anti-Neospora caninum antibodies. Electron microscopy showed single and grouped tachyzoites, with morphologic features similar to those of T. gondii. Polymerase chain reaction and deoxyribonucleic acid sequence analysis was consistent with T. gondii infection.

Aleutian Disease in Two Domestic Striped Skunks (Mephitis mephitis). Vet Pathol 44:687–690 (2007). Aleutian mink disease parvovirus (ADV) is known to infect several members of the Mustelidae family, with mink and ferrets being the most commonly reported hosts. Aleutian disease (AD) in adult animals is characterized by hypergammaglobulinemia and immune- complex disease. The most common form of AD involves a persistent infection due to the inability of the host immune response to neutralize and eliminate the virus. Lymphoplasmacytic infiltration of various organs, immune complex deposits in blood vessels, and severe mesangioproliferative glomerulonephritis ultimately lead to death.

Spontaneous Osteosarcoma in a Rabbit (Oryctolagus cuniculus). Vet Pathol 44:691–694 (2007). Proliferative and destructive lesions of bone were observed. On histologic examination, the tumor was composed of proliferating neoplastic cells that resembled histiocytes, with abundant osteoid production. A large number of multinucleated giant cells were found throughout.

Chronic Polymyositis Associated with Disseminated Sarcocystosis in a Captive-born Rhesus Macaque. Vet Pathol 44:695–699 (2007). diffuse pale streaking of the trunk, lumbar, and limb muscles were noted macroscopically. On histology, numerous elongated cysts that contained crescentshaped basophilic spores were found in the fibers of skeletal muscles. Scattered affected myofibers were degenerate and accompanied by eosinophilic-to-granulomatous inflammation.

Histopathologic Evidence of Capecitabine Corneal Toxicity in Dogs. Vet Pathol 44:700–702 (2007). Capecitabine (CPC) was administered as an oral immunosuppressive agent (renal transplant). Two dogs developed superficial keratitis, which was characterized by multifocal geographic erosions, superficial corneal epithelial pigmentation, and corneal neovascularization. These clinical signs correlated with the dose of CPC given. Ocular histopathologic abnormalities were limited to neovascularization and inflammatory infiltrate of the anterior corneal stroma and abnormal basal cell morphology, disorganization, thinning, and pigmentation of the corneal epithelium.

Spontaneously Occurring Alimentary Osteofluorosis Associated with Proliferative Gastroduodenopathy in Rabbits. Vet Pathol 44:703–706 (2007). Painful thickenings of the extremities, multiple osseous proliferations of extremities and mandibles and a mild to severe proliferative gastroduodenopathy. Histologically, periosteal and

endosteal hyperostosis and a mild to severe proliferation of the gastric and duodenal mucosa were noted. Major clinical manifestations of chronic fluoride intoxication are dental fluorosis and osteofluorosis. Dental fluorosis is characterized by enamel mottling and hypoplasia, and osteofluorosis by periosteal hyperostosis displaying a roughened irregular surface.

Multiple Hepatic Peribiliary Cysts in a Young Pig. Vet Pathol 44:707–709 (2007). All lobes of the liver contained numerous cysts of varying size containing serous fluid in all lobes. Histopathologically, the cysts were located mainly around the large bile duct and in the connective tissue of the portal tracts. The cysts were lined by a single layer of columnar, cuboidal, and flattened epithelial cells. Occasionally, goblet cells were observed. The epithelial cells were stained with periodic acid–Schiff/alcian blue and high-iron diamine/alcian blue, indicating the presence of neutral mucin, sialomucin, and sulfomucin.

Bronchioloalveolar Carcinoma Not Related to Jaagsiekte Sheep Retrovirus in a Goat. Vet Pathol 44:710–712 (2007). A lung tumor with the characteristics of bronchioloalveolar carcinoma was detected during histopathologic examination. The tumor cells were positive for surfactant proteins C and B, confirming that alveolar type II cells were the origin of the neoplasia. Tumor samples were tested by polymerase chain reaction, immunoblotting, and immunohistochemistry for the presence of Jaagsiekte sheep retrovirus (JSRV) and enzootic nasal tumor virus (ENTV), another retrovirus very closely related to JSRV, but all tests were negative. Therefore, this is the first reported case of spontaneous bronchioloalveolar carcinoma not related to JSRV or ENTV infection in a goat.

Internal Hydrocephalus and Associated Periventricular Encephalitis in a Young Fox. Vet Pathol 44:713–716 (2007). inflammatory and necrotizing lesions were observed in periventricular sites associated with diverticula and cleft formation in perithalamic areas and rhinencephalic cortex. Immunolabeling for Toxoplasma gondii, Neospora caninum, Encephalitozoon cuniculi, canine distemper virus, and rabies virus was negative.

Pathology of Inhalational Anthrax Infection in the African Green Monkey. Vet Pathol 44:716–721 (2007). Frequent gross lesions noted in the AGM were hemorrhage and edema in the lung, mediastinum, and mediastinal lymph nodes; pleural and pericardial effusions; meningitis; and gastrointestinal congestion and hemorrhage.Histopathologic findings included necrohemorrhagic lymphadenitis of mediastinal, axillary, inguinal, and mesenteric lymph nodes; mediastinal edema; necrotizing splenitis; meningitis; and congestion, hemorrhage, and edema of the lung, mesentery, mesenteric lymph nodes, gastrointestinal tract, and gonads.

Omental Leiomyoma in a Male Adult Horse. Vet Pathol 44:722–726 (2007). multiple white-to-yellow lobules. Histologically, the mass consisted of slightly pleomorphic spindloid-shaped cells arranged in interlacing bundles containing elongated nuclei with blunt ends. The majority of tumor cells revealed a positive immunoreaction for a-smooth

muscle actin, vimentin, and neuron-specific enolase and were negative for S-100, factor VIII–related antigen, and glial fibrillary acidic protein.

NovS-100 IHC- S-100 is normally present in cells derived from the neural crest (Schwann cells, melanocytes, and glial cells), chondrocytes, adipocytes, myoepithelial cells, macrophages, Langerhans cells, dendritic cells, and keratinocytes. S100 proteins are involved in regulation of protein phosphorylation, transcription factors, Ca++ homeostasis, the dynamics of cytoskeleton constituents, enzyme activities, cell growth and differentiation, and the inflammatory response. It can be found in melanomas, 50% of malignant peripheral nerve sheath tumors, and clear cell sarcomas.

Eosinophilic Substance is ‘‘Not Amyloid’’ in the Mouse Nasal Septum. Vet Pathol 44:796–802 (2007). An eosinophilic substance (ES) is usually observed in the mouse nasal septum and increases in volume with aging. It has been described as amyloid in textbooks and one report. However, it has been described as ‘‘not amyloid’’ in other reports because there was a negative reaction to Congo red. The ES reacted negatively to Congo red but was strongly positive to periodic acid–Schiff reaction with prior diastase treatment. In the electron microscope observation, the ES consisted of amorphous material and collagen, but no nonbranching fibrils. The above-mentioned findings indicated that the ES was not amyloid and suggested the ES might consist of not only collagen but also complex carbohydrate, which was produced by the nasal gland epithelial cells.

Tenascin-C in Chronic Canine Hepatitis: Immunohistochemical Localization and Correlation with Necro-Inflammatory Activity, Fibrotic Stage, and Expression of Alpha-Smooth Muscle Actin, Cytokeratin 7, and CD3+ Cells. Vet Pathol 44:803–813 (2007). TN-C is strongly correlated with increased fibrotic stage, inflammatory activity, and expression of CK7 and a-SMA. TN-C, CK7, and CD3 expression did not differ between diagnostic groups. Tenascin-C (TN-C) is one of the ECM proteins that has both adhesive and antiadhesive activities. In adult tissue, TN-C expression is absent or much reduced. However, expression is enhanced during processes involving ECM remodeling and cell migration, such as in tumor growth, fibrosis, and wound healing.

The Distribution and Density of Clostridium difficile Toxin Receptors on the Intestinal Mucosa of Neonatal Pigs. Vet Pathol 44:814–822 (2007). The most important virulence factors of C. difficile are 2 large exotoxins, toxin A (TcdA) and toxin B (TcdB). TcdA is a potent enterotoxin with effects on host tissues that are dependent upon receptor-mediated endocytosis of the intact toxin. TcdB is an effective cytotoxin, but it apparently does not bind receptors on intact mucosal epithelium. TcdB is much less toxic in vivo unless there is underlying damage to the mucosa, and it is not essential for the virulence of C. difficile. The receptors for TcdA in the pig remain to be identified, but a-galactosyl does not seem to be significant to its binding.

Immunohistochemical Expression of Vascular Endothelial Growth Factor and Vascular Endothelial Growth Factor Receptor Associated with Tumor Cell

Proliferation in Canine Cutaneous Squamous Cell Carcinomas and Trichoepitheliomas. Vet Pathol 44:823–830 (2007). It was concluded that VEGF and VEGFR-2 may promote tumor cell proliferation in TCPs and SCCs. An autocrine pathway for VEGF probably operates in canine SCCs and TCPs, as VEGF and VEGFR-2 expression was found in most tumors and was associated with evidence for tumor cell proliferation.

Naturally Occurring Parvovirus-associated Feline Hypogranular Cerebellar Hypoplasia—A Comparison to Experimentally-induced Lesions Using Immunohistology. Vet Pathol 44:831–841 (2007). In type 1 lesions, the cortex was nearly agranular, with an extremely thin molecular layer; the Purkinje cells were randomly placed and oriented, and their stunted main dendrite produced a thorn-covered atrophic dendritic tree; the basket cell axons ran randomly and had dysmorphic endings; and myelinated fibers were severely reduced in folia axes. In type 2 lesions, the cortex was hypogranular; the Purkinje cells were linearly organized, but their main dendrite extended too far in the molecular layer before giving up smooth, bent secondary dendrites; many basket cells were located along the cerebellar surface, and their axons ran at right angle to the surface; myelinated fibers were moderately reduced. Defects in climbing fiber synapse translocation and elimination were evident in both types of lesion. viral NS1 protein cytotoxicity might explain degenerative changes in the Purkinje cells that were present, in addition to the development defect.

Mammary Invasive Micropapillary Carcinoma in Cats: Clinicopathologic Features and Nuclear DNA Content. Vet Pathol 44:842–848 (2007). Invasive micropapillary carcinoma (IMC) is a variant of infiltrating ductal carcinoma of the breast associated with poor outcome. IMC’s have features of high biologicaggressiveness and should be classified as independent histologic types of FMC.

Equine Multinodular Pulmonary Fibrosis: A Newly Recognized Herpesvirus-Associated Fibrotic Lung Disease. Vet Pathol 44:849–862 (2007). Gross lesions consisted of multiple nodules of fibrosis throughout the lungs. Histologically, there was marked interstitial fibrosis, often with preservation of an ‘‘alveolarlike’’ architecture, lined by cuboidal epithelial cells. The airways contained primarily neutrophils and macrophages. Rare macrophages contained large eosinophilic intranuclear viral inclusion bodies. Caused by γ-herpesvirus, EHV-5.

Lesion Development and Immunohistochemical Changes in Granulomas from Cattle Experimentally Infected with Mycobacterium bovis. Vet Pathol 44:863–874 (2007). Early granulomas- moderate Acid-fast bacilli, Abundant iNOS. Late granulomas- large numbers of acid-fast bacteria, less iNOS and CD8+ cells. The relative number of CD4+ and CD68+ cells remained constant throughout the study. Diminished expression of iNOS and reduced numbers of CD8+ and γ/d T cells late in the progression of tuberculous granulomas may represent a failure of the host response to control infection.

Immunohistochemical Detection of Multiple Myeloma 1/Interferon Regulatory Factor 4 (MUM1/IRF-4) in Canine Plasmacytoma: Comparison with CD79a and

CD20. Vet Pathol 44:875–884 (2007). 1) Antibody Mum-1p is very specific for canine plasmacytomas, 2) antibody Mum-1p is superior in sensitivity and specificity to CD79a and CD20 for the identification of canine plasmacytomas in formalin-fixed, paraffin-embedded tissues, 3) canine lymphomas that express MUM1/IRF4 are few and usually of B-cell origin, 4) other canine leukocytic and melanocytic tumors do not express MUM1/IRF4.

Nasal and Nasopharyngeal Lymphoma in Cats: 50 Cases (1989–2005). Vet Pathol 44:885–892 (2007). Lymphoma is the most common nasal cavity tumor in cats. Histologically, all were considered diffuse lymphoid neoplasms and no cats displayed features of follicular lymphoma. 32 were uniformly positive for CD79a, 7 were uniformly CD3 positive, and 6 had a mixed population of CD79a and CD3 cells. Epithelioptropism was exhibited in 4 of 5 (80%) cats in which there was sufficient epithelium present for evaluation. The most common biochemical abnormalities were panhyperproteinemia in 26/46 (57%) of cats and hypocholesterolemia in 11/46 (24%) of cats.

Expression of the Embryonic Transcription Factor Oct4 in Canine Neoplasms: A Potential Marker for Stem Cell Subpopulations in Neoplasia. Vet Pathol 44:893–900 (2007). Oct4 has been consistently associated with pluripotent or stemlike cells, and it is hypothesized that Oct4 is necessary for the maintenance of pluripotency. We hypothesize that Oct4- positive cells are present in all canine neoplasms and that these subpopulations of neoplastic cells might represent ‘‘cancer stem’’ cells. All tumors included in this study contained a subpopulation of Oct4-positive cells.

A Soluble Secreted Glycoprotein (eCLCA1) is Overexpressed Due to Goblet Cell Hyperplasia and Metaplasia in Horses with Recurrent Airway Obstruction. Vet Pathol 44:901–911 (2007). Horses affected by RAO had strong goblet cell metaplasia in bronchioles and goblet cell hyperplasia in bronchi and the trachea. Expression of the eCLCA1 protein was tightly linked to all airway goblet cells in both groups. SO, eCLCA1 is a secreted glycoprotein and not an integral membrane protein. Taken together, the results suggest that eCLCA1 mediates its effect as a soluble constituent of airway mucins that is overexpressed in RAO airways because of goblet cell hyperplasia and metaplasia, not transcriptional upregulation.

Leukoencephalomyelopathy in Specific Pathogen-free Cats. Vet Pathol 44:912–916 (2007). bilateral axonal degeneration within white matter regions of the cervical, thoracic, and lumbar spinal cord and in the white matter of the cerebral internal capsule and peduncle, in the roof of the fourth ventricle and inferior cerebellar peduncle, and in the external arcuate and pyramidal fibres of the medulla. There were varying degrees of accompanying microgliosis, astrocytosis, and capillary hyperplasia.

Granulomatous and Eosinophilic Rhinitis in a Cow Caused by Pseudallescheria boydii Species Complex (Anamorph Scedosporium apiospermum). Vet Pathol 44:917–920 (2007). Grossly multifocal-to-coalescing, raised, ulcerated firm nodules were present in both nares. Histologically, the lamina propria was expanded by intense

infiltrates of eosinophils, epithelioid macrophages, multinucleate giant cells, lymphocytes, and plasma cells. Associated with the inflammatory cells were variably sized, septate hyphae, 5–8 mm in diameter, admixed with numerous, terminal conidia, 6–30 mm in diameter, with a discrete outer wall identified by culture as Pseudallescheria boydii species complex (anamorph Scedosporium apiospermum). The asexual form or anamorph is S. apiospermum. Both forms produce conidia in culture, but only P. boydii forms fertile fruiting bodies for sexual reproduction (teleomorph). The 2 forms represent a single species belonging to order Microascales, phylum Ascomycota.

Pulmonary Lymphomatoid Granulomatosis in a Dog: Evidence of immunophenotypic Diversity and Relationship to Human Pulmonary Lymphomatoid Granulomatosis and Pulmonary Hodgkin’s Disease. Vet Pathol 44:921–923 (2007). Histopathologic examination showed a mixed population of atypical lymphoid cells that had infiltrated into the pulmonary blood vessels angiocentrically. The lymphocytes were CD3 positive, consistent with a pan-T-cell phenotype. The lymphoid cells in the lesion were also positive for CD20cy and CD79a, indicative of the presence of B cells. We also observed large Reed- Sternberg–like cells (large pleomorphic and binucleated nuclei) that were positive for CD15 and CD30, similar to observations in human pulmonary Hodgkin’s disease (PHD). In conclusion, canine PLG in this Cocker Spaniel was associated with B and T cells, which is first identified in a case of canine PLG. It was histopathologically similar to human lymphomatoid granulomatosis and immunophenotypically similar to human PHD.

Feline Cutaneous Viral Papilloma Associated with Human Papillomavirus Type 9. Vet Pathol 44:924–927 (2007). multinodular exophytic mass on the dorsal surface of the nose. Histologic examination revealed hyperkeratosis, epidermal hyperplasia, papillomatosis, koilocytosis, and possible intranuclear viral inclusions. Polymerase chain reaction amplified papillomaviral deoxyribonucleic acid from formalin-fixed samples of the lesion. Sequencing of the amplicon revealed 98% similarity to human papillomavirus (HPV) type 9.

Mimosa tenuiflora as a Cause of Malformations in Ruminants in the Northeastern Brazilian Semiarid Rangelands. Vet Pathol 44:928–931 (2007). Craniofacial anomalies, eye malformations, and permanent flexures of the forelimbs. abnormalities similar to those observed in field cases, including cleft lip, unilateral corneal opacity, ocular bilateral dermoids, buphthalmos with a cloudy brownish appearance of the anterior chamber due to an iridal cyst, and segmental stenosis of the colon. Malformations induced experimentally by M. tenuiflora were similar to those observed in field cases.

Calcium Diacylglycerol Guanine Nucleotide Exchange Factor I (CalDAG-GEFI) Gene Mutations in a Thrombopathic Simmental Calf. Vet Pathol 44:932–935 (2007). Simmental thrombopathia is an inherited platelet disorder that closely resembles the platelet disorders described in Basset Hounds and Eskimo Spitz dogs. Recently, two different mutations in the gene encoding calcium diacylglycerol guanine nucleotide exchange factor I (CalDAG-GEFI) were described to be associated with the Basset Hound and Spitz thrombopathia disorders, and a third distinct mutation was identified in

CalDAG-GEFI in thrombopathic Landseers of European Continental Type. This change is likely responsible for the thrombopathic phenotype observed in Simmental cattle and underscores the critical nature of this signal transduction protein in platelets.

Histologic and Immunohistochemical Characterization of a Testicular Mixed Germ Cell Sex Cord-Stromal Tumor and a Leydig Cell Tumor in a Dog. Vet Pathol 44:936–943 (2007). Histologically, MGSCT consisted of two nodules ofseminiferous tubules lined by germ cells and Sertoli cells in variable proportions. Germ cells had variable size and nuclear features, with frequent giant cells. Germ cells were evenly mixed with Sertoli cells or located in the center of tubules. Markers that labeled mainly germ cells and few or no Sertoli or Leydig cells were calretinin, KIT, and PGP 9.5. E-cadherin, GATA-4, inhibin-a (INH-a), and neuron-specific enolase (NSE) were predominantly detected in Sertoli cells, whereas melan A was particularly expressed in Leydig cells and vimentin in all three cell types.

Immunohistochemical Demonstration of the Putative Canine Distemper Virus Receptor CD150 in Dogs with and without Distemper. Vet Pathol 44:943–948 (2007). Signaling lymphocyte activation molecule (SLAM) or CD150 can function as a receptor for the canine distemper virus (CDV) in vitro. Additionally, virus infection isassociated with up-regulation of SLAM, potentially causing an amplification of virus in the host. SLAM labeling was also found in multiple organs, including footpad lymph nodes, lung, transitional cell epithelium of the urinary tract, and in the stomachs and intestines of control dogs (Nos. 1–7) and CDV-infected dogs.

Congenital Unilateral Absence of the Corticospinal Tract in a Siamese Cat. Vet Pathol 44:949–951 (2007). Pathologic investigation revealed unilateral (right-sided) absence of the corticospinal (pyramidal) tract throughout its normal course. Although an infectious cause cannot be completely ruled out a genetic etiology was suspected.

Subcutaneous Neoplasms of the Ventral Abdomen with Features of Adrenocortical Tumors in Two Ferrets. Vet Pathol 44:951–955 (2007). neoplasms were composed of islands of polygonal cells separated by interlacing streams of spindloid cells reminiscent of ferret adrenocortical tumors with smooth muscle proliferation. Immunohistochemically, the polygonal cells demonstrated strong cytoplasmic reactivity for inhibin and weak cytoplasmic reactivity for pancytokeratin and S-100 protein. Spindloid cells demonstrated strong cytoplasmic reactivity for alpha smooth muscle actin, muscle-specific actin, desmin, and glial fibrillary–associated protein. Ultrastructurally, the polygonal cells contained numerous intracytoplasmic clear vacuoles, mitochondria, scant rough endoplasmic reticulum, and few intermediate filaments. suggestive of adrenocortical tumors with smooth muscle proliferation, but cannot be differentiated from an ovarian gonadal stromal tumor.

Sarcocystis neurona Encephalitis in a Dog. Vet Pathol 44:956–961 (2007). Multiple foci of encephalitis were found in the cerebrum and particularly in the cerebellum. Protozoa morphologically consistent with Sarcocystis sp. were identified at sites of

intense inflammation and malacia. Additionally, multiple schizonts were identified in areas without inflammation. Immunohistochemistry using both polyclonal and monoclonal antibodies specific for Sarcocystis neurona was strongly positive. No reaction to polyclonal antisera for Toxoplasma gondii or Neospora caninum wasfound. Polymerase chain reaction confirmed that the protozoa were S. neurona.