BONE

JOINT

SOFT TISSUE

Modeling/RE-modeling

CELLS of BONE• OSTEOPROGENITOR (“STEM”)(TGFβ)• OSTEOBLASTS (surface of spicule), under

control of calcitonin to take blood calcium and put it into bone.

• OSTEOCYTES (are osteoblasts which are now completely surrounded by bone)

• OSTEOCLASTS (macrophage lineage), under control of PTH to chew up the calcium of bone and put it into blood

Proteins (organic) of BONE• Type 1 (TYPE [B]ONE) collagen (90%)• Cell adhesion proteins, i.e. CAMs: Osteopontin,

fibronectin, thrombospondin• Calcium-binding proteins: Osteonectin, sialoprotein• Proteins involved in mineralization: Osteocalcin  • Enzymes: Collagenase, Alk. Phos.• Growth factors

– IGF-1, TGF-β, PDGF  

• Cytokines– Prostaglandins, IL-1, IL-6, RANKL

• Proteins Concentrated from Serum– β2 –microglobulin Albumin– IGF, insulin-like growth factor– TGF, transforming growth factor– PDGF, platelet-derived growth factor– IL, interleukin– RANKL, RANK ligand

Minerals (IN-organic) of BONEHYDROXY-APATITE

Ca5(PO4)3(OH) Ca10(PO4)6(OH)2

ADJECTIVES of BONE•Compact

– Dense– Cortical

•Spongy– Cancellous– Membranous– Endosteal– Spicular

Woven vs. “Lamellar”

-BLASTS/-CLASTS

Ca++ PTH

Ca++ Calcitonin

BONE DISEASES• 1) MALFORMATIONS AND DISEASES CAUSED BY DEFECTS IN NUCLEAR PROTEINS

AND TRANSCRIPTION FACTORS, polydactyly, syndactyly, absence of a bone• 2) DISEASES CAUSED BY DEFECTS IN HORMONES AND SIGNAL TRANSDUCTION

MECHANISMS, achondroplasia, thanatophoria• 3) DISEASES ASSOCIATED WITH DEFECTS IN EXTRACELLULAR STRUCTURAL

PROTEINS– Type 1 Collagen Diseases (Osteogenesis Imperfecta)– Types 2, 10, and 11 Collagen Diseases

• 4) DISEASES ASSOCIATED WITH DEFECTS IN FOLDING AND DEGRADATION OF MACROMOLECULES

– Mucopolysaccharidoses• 5) DISEASES ASSOCIATED WITH DEFECTS IN METABOLIC PATHWAYS (ENZYMES,

ION CHANNELS, AND TRANSPORTERS)– Osteopetrosis

• 6) DISEASES ASSOCIATED WITH DECREASED BONE MASS– Osteoporosis

• 7) DISEASES CAUSED BY OSTEOCLAST DYSFUNCTION– Paget Disease (Osteitis Deformans)

• 8) DISEASES ASSOCIATED WITH ABNORMAL MINERAL (Ca++) HOMEOSTASIS– Ricketts and Osteomalacia– Hyperparathyroidism– Renal Osteodystrophy

1) MALFORMATIONS AND DISEASES CAUSED BY DEFECTS IN NUCLEAR PROTEINS AND “TRANSCRIPTION FACTORS”

proteinDNAmRNA

• Congenital absence of a, usually single, bone: phalanx, rib, clavicle

• Supernumerary digit (polydactyly)

• Syndactyly

• CRANIORACHISCHISIS

2) DISEASES CAUSED BY DEFECTS IN HORMONES AND

SIGNAL TRANSDUCTION MECHANISMS

• Achondroplasia, dwarf (non-lethal)• Thanatophoria, dwarf (lethal, FGF-3

mutations)

• a point mutation (usually Arg for Gly375) in the gene that codes for FGF receptor 3 (FGFR3), which is located on the short arm of chromosome 4. In the normal growth plate, activation of FGFR3 inhibits cartilage proliferation, hence the term “achondroplastic”;

• A MUTATION causes FGFR3 to be constantly activated.

Short arms and extra folds of skin

Achondroplastic “dwarf” Thanatophoric “dwarf”, often lethal

3) DISEASES ASSOCIATED WITH DEFECTS IN EXTRACELLULAR

STRUCTURAL PROTEINS• OSTEOGENESIS IMPERFECTA TYPES• (“Brittle” bone disease, too LITTLE bone),

BLUE sclerae• Mutations in genes which code for the

alpha-1 and alpha-2 chains of COLLAGEN 1• Mutations of COLLAGEN 2,10, 11 manifest

themselves as CARTILAGE diseases, ranging from joint cartilage destruction to fatal sequelae

Osteogenesis Imperfecta

BLUE SCLERA

4) DISEASES ASSOCIATED WITH DEFECTS IN FOLDING AND

DEGRADATION OF MACROMOLECULES(glycosaminoglycans)

• MUCOPOLYSACCHARIDOSIS (one of MANY lysosome storage diseases)

• DECREASES in ENZYMES which degrade:– DERMATAN

– HEPARAN

– KERATAN

• Chiefly CARTILAGE disorders: short, chest wall, malformed bones

MUCOPOLYSACCHARIDOSES

5) DISEASES ASSOCIATED WITH DEFECTS IN METABOLIC

PATHWAYS (ENZYMES, ION CHANNELS, AND TRANSPORTERS)

• OSTEOPETROSIS, 4 types

• One common one has a CARBONIC

ANHYDRASE deficiency, i.e., ↓ acid

• DECREASED osteoclast resorption

• “MARBLE” bone, increased bone, brittle, sclerotic bone

OSTEOPETROSIS

6) DISEASES ASSOCIATED WITH DECREASED BONE MASS

•OSTEOPOROSIS• “PEAK” bone mass is early adulthood• Normal decline, slow• Osteoporosis is accelerated bone loss• Factors:

– AGE– Physical activity– Estrogen withdrawal (menopause)– Nutrition (Ca++)– Genetics

Categories of Generalized OsteoporosisPrimary  

Postmenopausal Idiopathic  

Senile  

Secondary  

Endocrine disorders Rheumatologic disease

Hyperparathyroidism   Drugs

Hypo-hyperthyroidism   Anticoagulants  

Hypogonadism   Chemotherapy  

Pituitary tumors   Corticosteroids  

Diabetes, type 1   Anticonvulsants  

Addison disease   Alcohol  

Neoplasia MiscellaneousMultiple myeloma   Osteogenesis imperfecta  

Carcinomatosis   Immobilization  

Gastrointestinal Pulmonary disease  

Malnutrition, Malbs., Hepatic Insuf., Vit C,D   Homocystinuria  

Anemia  

 

 

OSTEOPOROSIS

7) DISEASES CAUSED BY OSTEOCLAST DYSFUNCTION

Paget Disease (Osteitis Deformans)

• Matrix madness, Osteoblasts/-cytes gone wild• THREE PHASES:

– 1) Increased osteoclast resorption– 2) Increased “hectic” bone formation (osteoblasts)– 3) Osteosclerosis

• ELEVATED ALKALINE-PHOSPHATASE • ELEVATED urine HYDROXYPROLINE

PAGET’s DISEASE (of BONE)

85% MONOSTOTIC, WHOLE BONE

15% POLY-OSTOTIC (skull, pelvis)

“JIGSAW”, NOT LAMINAR, BONE

CLINICAL: PAIN!!!

(MICROFRACTURES)

PAGET’s DISEASE

NON-Lamellar bone

8) DISEASES ASSOCIATED WITH ABNORMAL MINERAL

HOMEOSTASIS– Ricketts and Osteo”malacia”

• VITAMIN D deficiency/dysfunction– Hyperparathyroidism, PRIMARY (PTH ADENOMA)

• ENTIRE SKELETON• OSTEITIS FIBROSIS CYSTICA (von Recklinghausen’s

disease (of bone)• “BROWN”* TUMOR

– Hyperparathyroidism, SECONDARY (RENAL) (NOT AS SEVERE AS 1º)

– Renal Osteodystrophy = ANY bone disorder due to chronic renal disease

PRIMARY HYPERPARATHYROIDISM

OSTEITIS FIBROSA CYSTICA

“BROWN” “TUMOR”

RENAL OSTEODYSTROPHY

• PHOSPHATE RETENTION

• HYPOPHOSPHATEMIA

• HYPOCALCEMIA

• INCREASED PTH

• INCREASED OSTEOCLASTS

• METABOLIC ACIDOSIS release of HYDROXYAPATITES from matrix

FRACTURES

FRACTURES, adjectives

• Complete, incomplete

• Closed, open (communicating)

• Communited (splintered, “greenstick”)

• Displaced (NON-aligned)

• PATHOGENIC, (non-traumatic, 2º to other disease, often metastases)

• “STRESS” fracture

FRACTURES• THREE PHASES

– HEMATOMA, minutes days PDGF, TGF-β, FGF– SOFT CALLUS (“PRO”-CALLUS), ~1 week– HARD CALLUS (BONY CALLUS), several weeks

• COMPLICATIONS– PSEUDARTHROSIS (non-union)– INFECTION (especially OPEN [communicating]

fractures)

FRACTURES

OSTEONECROSIS• Also called AVASCULAR necrosis• Also called ASEPTIC necrosis

• CAUSE: ISCHEMIA– Trauma– Steroids– Thrombus/Embolism– Vessel injury, e.g., radiation– INCREASED intra-osseous pressurevascular

compression– Venous hypertension too

OSTEONECROSISDisorders Associated with Osteonecrosis

Idiopathic Pregnancy

Trauma Gaucher disease

Corticosteroid administration

Sickle cell and other anemias

Infection Alcohol abuseDysbarism Chronic pancreatitis

Radiation therapy Tumors

Connective tissue disorders

Epiphyseal disorders

OSTEONECROSIS

OSTEONECROSIS

OSTEOMYELITIS• Pyogenic: Staph, E. coli, Pseudom, Kleb,

Salmonella

– Hematogenous

– Contiguous, e.g., from a nearby joint

– Direct implantation

• TB

• Syphilis

OSTEOMYELITIS• DX: X-ray, Bone scan

OSTEOMYELITIS• DX: Histology

OSTEOMYELITIS• COMPLICATIONS

– Subperiosteal abscess

– Draining sinus

– Joint involvement

• SEQUESTRUM (dead bone)

vs.

• INVOLUCRUM (new bone)

OSTEOMYELITIS• Tuberculous

– Usually blood borne– TB of spine is known as POTTS

disease

• Syphilis– CONGENITAL– TERTIARY, “SABRE” shins

POTT’s DISEASE

SABER SHINS

Classification of Primary Tumors Involving BonesHistologic Type Benign MalignantHematopoietic (40%) Myeloma

Malignant lymphomaChondrogenic (22%) Osteochondroma Chondrosarcoma

Chondroma Dedifferentiated chondrosarcoma

Chondroblastoma Mesenchymal chondrosarcoma

Chondromyxoid fibroma

Osteogenic (19%) Osteoid osteoma Osteosarcoma

OsteoblastomaUnknown origin (10%) Giant cell tumor tumor

Giant cell tumorAdamantinoma

Histiocytic origin Fibrous histiocytoma Malignant fibrous histiocytoma

Fibrogenic Metaphyseal fibrous defect (fibroma) Desmoplastic fibroma

FibrosarcomaNotochordal ChordomaVascular Hemangioma Hemangioendothelioma

HemangiopericytomaLipogenic Lipoma LiposarcomaNeurogenic Neurilemmoma

BONE TUMORS• BONE

• CARTILAGE

• FIBROUS

• MISC.–Ewing’s “sarcoma”

–Giant Cell Tumor

–METASTASES

BONE- BONE TUMORS

• OSTEOMA

• OSTEOID OSTEOMA (nidus)

• OSTEOBLASTOMA

• OSTEOSARCOMA (OSTEOGENIC SARCOMA)

OSTEOMA• SOLITARY

• MIDDLE AGE

• FROM SUBPERIOSTEAL or ENDOSTEAL surfaces

• SKULL, FACE, most common

• Totally BENIGN

• To be distinguished from REACTIVE BONE, (can be difficult)

Why am I not showing you HISTOLOGY?

FRONTAL SINUS

OSTEOID OSTEOMA• At least 2 cm in diameter

• Teens, twenties, APPENDICULAR skeleton

• M>>F

• PAINFUL

• Has a NIDUS• Responds to aspirin

• Induces a MARKED bony reaction

NIDUS

OSTEOBLASTOMA• AXIAL SKELETON, i.e., SPINE

• NO nidus

• NO bony reaction

• NOT relieved by aspirin

OSTEOSARCOMA(OSTEOGENIC SARCOMA)

LATE TEENSKNEESMETAPHYSESPAINFUL!!!

TYPES of OSTEOSARCOMAS• The anatomic portion of the bone from which they

arise (intramedullary, intracortical, or surface) • Degree of differentiation • Multicentricity (synchronous, metachronous[NOT

synchronous]) • Primary (pre-existing bone is unremarkable) or

secondary (e.g., osteosarcoma associated with pre-existing disorders such as benign tumors, Paget disease, bone infarcts, previous irradiation)

• Histologic variants (osteoblastic, chondroblastic, fibroblastic, telangiectatic, small cell, and giant cell)

The most common subtype is osteosarcoma that arises in the metaphysis of long bones; is primary, solitary, intramedullary, and poorly differentiated; and produces a predominantly bony matrix

BONE- CARTILAGE TUMORS

• OSTEOCHONDROMA (EXOSTOSIS)

• CHONDROMA

• CHONDROBLASTOMA

• CHONDROMYXOID FIBROMA

• CHONDROSARCOMA

OSTEOCHONDROMA (EXOSTOSIS)

• Common, Cartilage AND Bone present

• Often MULTIPLE as a hereditary syndrome

• M>>>F

• PELVIS, SCAPULAE, RIBS

CHONDROMA• Chondroma vs. EN-chondroma• PURE Hyaline Cartilage• MULTIPLE enchondromas = Ollier’s dis.• Maffucci Synd. if hemangiomas present

CHONDROBLASTOMA• RARE, in teenagers

• M>>F

• KNEES, usually

• Epiphyses

• MUCH LESS matrix than a chondroma

CHONDROMYXOID FIBROMA• RAREST of all• TEENS, MALES• “MYXOID” concept• “ATYPIA”

CHONDROSARCOMA• ANATOMY

– INTRAMEDULLARY– JUXTACORTICAL

• HISTOLOGY– CONVENTIONAL

• HYALINE• MYXOID

– CLEAR– DE-DIFFERENTIATED– MESENCHYMAL

CHONDROSARCOMA

BONE- FIBROUS TUMORS

• FIBROUS CORTICAL DEFECT/NON-OSSIFYING FIBROMA

• FIBROUS DYSPLASIA

• FIBROSARCOMA/MALIGNANT FIBROUS HISTIOCYTOMA

FIBROUS CORTICAL DEFECT• COMMON, usually LESS

THAN 1 CM

• CHILDREN >2

• IF MORE THAN 5-6 CM, they are then called NON-OSSIFYING FIBROMA

FIBROUS “DYSPLASIA”• BENIGN TUMOR

• THREE TYPES– SINGLE BONE (70%)

– POLY-OSTOTIC (27%)

– POLY-OSTOTIC (3%) with café-au-lait and endocrine disorders, especially precocious puberty

1) CURVED thin spicules

2) LACK of osteoblastic “rimming”

FIBROSARCOMA/MFH

• METAPHYSES of LONG BONES

• PELVIC FLAT BONES

• LYTIC

• FRACTURES

• OF COURSE, SARCOMATOUS METASTASIS

FIBROSARCOMA/MFH

MISC. TUMORS of BONE

• EWING sarcoma/PNET

(Primitive NeuroEctodermal

Tumor)

• GIANT CELL TUMOR

• METASTASES

EWING/PNET• SAME TUMOR

• SMALL ROUND BLUE CELL TUMOR

• NEUROENDOCRINE CELL ORIGIN

• CHROMOSOME TRANSLOCATION 11&22

• SECOND most COMMON bone malignancy in CHILDREN

• ARISE IN MEDULLARY CAVITY of BONE

• LOOK LIKE LYMPHOMA

GCT (Giant Cell Tumor), BONE

METASTASESMALE: PROSTATEFEMALE: BREASTRENAL, THYROID also seek bone early also

LYTIC?BLASTIC?

SYNOVIAL JOINTS

TWO KINDS of cells form the synovial intima

• 1) fibroblasts– Hyaluronin

– Lubricin

• 2) macrophagesThe SUB-intima is loose CT or fat

JOINT DISEASES•“ARTHRITIS”

–DEGENERATIVE (OSTEOARTHRITIS)

–RHEUMATOID– “JUVENILE” RHEUMATOID– NON-INFECTIOUS: Ankylosing Spond.,

Reactive, Psoriasis, IBD– INFECTIOUS: Supp., TB, Lyme, Viral– GOUT (URATE)– PSEUDOGOUT (PYROPHOSPHATE)

• Tumors (all are of synovium)– Ganglion (Synovial Cyst), non-neoplastic– Giant Cell Tumor (Pigmented VilloNodular Synovitis[PVNS]), benign– Synovial Sarcoma, malignant

“DEGENERATIVE” ARTHRITISaka, “OSTEO”ARTHRITIS

• Etiology/Risk Factors: Age, Trauma, Genes

• Pathogenesis: Progressive EROSION of articular cartilage

• Morphology: X-Ray, “eburnation”, “joint mice”, osteophytes

• Clinical Expression: PAIN, Limitation of motion

HEBERDEN’S NODES

DIP, NOT MP or PIP

RHEUMATOID ARTHRITIS Rheumatoid arthritis (RA) is a

chronic systemic inflammatory disorder that may affect many tissues and organs—skin, blood vessels, heart, lungs, and muscles—but principally attacks the joints, producing a nonsuppurative proliferative and inflammatory synovitis that often progresses to destruction of the articular cartilage and ankylosis of the joints.

TWO KINDS of cells form the synovial intima

• 1) fibroblasts– Hyaluronin

– Lubricin

• 2) macrophagesThe SUB-intima is loose CT or fat

RHEUMATOID ARTHRITIS• Etiology/Risk Factors: Autoimmune

• Pathogenesis: Progressive SYNOVITIS

• Morphology: Synovial lymphocytes, macrophages, plasma cells, neutrophils,

osteoclasts, “pannus”, hyperemia, rheumatoid “nodules”, vasculitis

• Clinical Expression: PAIN, Limitation of motion, malaise, fatigue, rheumatoid factor IgMIgG-Fc,

The rheumatoid “nodule” shows “palisading” fibroblasts

HANDSWRISTELBOWS

DIAGNOSIS• CLINICAL FEATURES (1% of population F>>M)

– MORNING STIFFNESS, MEAN AGE 45 YRS– ARTHRITIS in MORE THAN 3 JOINT AREAS– “TYPICAL” hand findings, MP ULNAR deviation– SYMMETRIC ARTHRITIS– SERUM RHEUMATOID FACTOR– “TYPICAL” X-RAY findings

“JUVENILE” Rheumatoid Arthritis

• Begins BEFORE age 16, by definition

• Generally LARGER joints than RA

• Often POSITIVE ANA

“SERONEGATIVE” ARTHRITIDES• ANKYLOSING SPONDYLITIS (aka,

“rheumatoid” spondylitis, or Marie-Strumpell Disease [HLA-B27] (M>>F)

• “REACTIVE” ARTHRITIS (FOLLOWS GU or GI INFECTIONS)– REITER SYDROME (urethral &

conjunctival inflammation too) [HLA-B27]

– Arthritis associated with IBD

• PSORIATIC ARTHRITIS [HLA-B27]

Ankylosing Spondylitis

INFECTIOUS ARTHRITIS• From OSTEOMYELITIS• USUALLY SUPPURATIVE

• GC, staph, strep, H. flu, E. coli, (Salmonella in sicklers)

• 4 cardinal signs, fever,

leukocytosis, ESR

INFECTIOUS ARTHRITIS• TB• LYME Disease, i.e., Borrelia

burgdorferi, from Ixodes ticks• VIRAL

–Parvovirus B19–Rubella–Hepatitis C

GOUT• Endpoint of HYPERURICEMIA from

ANY cause resulting in JOINT deposition of monosodium urate crystals (TOPHI)– ACUTE– CHRONIC

• 10% of population has hyperuricemia (>7 mg/dl), but only 1/20 of these has gout

Classification of GoutClinical Category Metabolic Defect

Primary Gout (90% of cases)

Enzyme defects unknown (85%–90% of primary gout)

■ Overproduction of uric acid

  Normal excretion (majority)  

  Increased excretion (minority)  

  Underexcretion of uric acid with normal   production

Known enzyme defects—e.g., partial HGPRT deficiency (rare)

■ Overproduction of uric acid

Secondary Gout (10% of cases)

Associated with increased nucleic acid turnover—e.g., leukemias

■ Overproduction of uric acid with increased urinary excretion

Chronic renal disease ■ Reduced excretion of uric acid with normal production

Inborn errors of metabolism—e.g., complete HGPRT deficiency (Lesch-Nyhan syndrome)

■ Overproduction of uric acid with increased urinary excretion

HGPRT, hypoxanthine guanine phosphoribosyl transferase.

HYPERURICEMIA GOUT• Age of the individual and duration of the

hyperuricemia are factors. Gout rarely appears before 20 to 30 years of hyperuricemia. M>>F

• Genetic predisposition is another factor. In addition to the well-defined X-linked abnormalities of HGPRT, primary gout follows multifactorial inheritance and runs in families.

• Heavy alcohol consumption predisposes to attacks of gouty arthritis.

• Obesity increases the risk of asymptomatic gout. • Certain drugs (e.g., thiazides) predispose to the

development of gout. • Lead toxicity increases the tendency to develop

gout

FEATURES• TOPHACEOUS ARTHRITIS

• GOUTY NEPHROPATHY

GOUTY NEPHROPATHY

GOUT• Associated with ATHEROSCLEROSIS

• Associated with HYPERTENSION

Pseudo-GOUT• Gout: Monosodium Urate• Pseudo-GOUT: Calcium Pyrophosphate

• PSEUDOGOUT is also called CHONDROCALCINOSIS, or CPPD (Calcium Phosphate Deposition Disease)

• IDIOPATHIC, HEREDITARY, SECONDARY

–Secondary joint damage, hyperparathyroidism, hemochromatosis, hypomagnesemia, hypothyroidism, ochronosis, and diabetes

GOUT vs. PSEUDOGOUT

JOINT TUMORS• BENIGN

– GANGLION (SYNOVIAL CYST)– GIANT CELL TUMOR of TENDON SHEATH,

aka PVNS, Pigmented VilloNodular Synovitis

• MALIGNANT– SYNOVIAL SARCOMA

GANGLION

PVNS/GCT

Synovial Sarcoma

“SOFT TISSUE” TUMORS

• FAT

• FIBROUS TISSUE

• FIBROHISTIOCYTIC

• SKELETAL MUSCLE

• SMOOTH MUSCLE

• VASCULAR

• PERIPHERAL NERVE• UNCERTAIN: SYNOVIAL SARCOMA, ALVEOLAR

SOFT PART SARCOMA, EPITHELIOD SARCOMA

CAUSES• MOSTLY UNKNOWN• RADIATION association• CHEMICAL BURN association• THERMAL BURN association• TRAUMA association• VIRUS association (HHV8 for Kaposi)• GENETICS• Parts of many SYNDROMES• MANY TRANSLOCATIONS

Chromosomal and Genetic Abnormalities in Soft Tissue Sarcomas

Tumor Cytogenetic Abnormality Genetic Abnormality

Extraosseous Ewing sarcoma and primitive neuroectodermal tumor

t(11:22)(q24;q12) FLI-1-EWS fusion gene

  t(21:22)(q22;q12) ERG-EWS fusion gene

  t(7;22)(q22;q12) ETV1-EWS fusion gene

Liposarcoma—myxoid and round cell type

t(12:16)(q13;p11) CHOP/TLS fusion gene

Synovial sarcoma t(x;18)(p11;q11) SYT-SSX fusion gene

Rhabdomyosarcoma—alveolar type t(2;13)(q35;q14) PAX3-FKHR fusion gene

  t(1;13)(p36;q14) PAX7-FKHR fusion gene

Extraskeletal myxoid chondrosarcoma t(9;22)(q22;q12) CHN-EWS fusion gene

Desmoplastic small round cell tumor t(11;22)(p13;q12) EWS-WT1 fusion gene

Clear cell sarcoma t(12;22)(q13;q12) EWS-ATF1 fusion gene

Dermatofibrosarcoma protuberans t(17:22)(q22;q15) COLA1-PDGFB fusion gene

Alveolar soft part sarcoma t(X;17)(p11.2;q25) TFE3-ASPL fusion gene

Congenital fibrosarcoma t(12;15)(p13;q23) ETV6-NTRK3 fusion gene

SOFT TISSUE TUMORS

• ALL “SPINDLY”

• Deep (desmoid) vs. Superficial (skin)

• Importance of counting MITOSES• Importance of STAGING

• Importance of IMMUNOPEROXIDASE

• Importance of CONSULTATION

FAT• LIPOMA

• LIPOSARCOMA

NORMAL FAT LIPOMA, encapsulated

LIPOSARCOMA, often retroperitoneal

FIBROUS TISSUE• NODULAR FASCIITIS

(pseudosarcomatous)• FIBROMATOSES

(plantar, palmar, penile)• FIBROSARCOMA

MYOSITIS OSSIFICANS• BENIGN FIBROUS TISSUE

PROLIFERATION PLUS OSSEOUS “METAPLASIA”

FIBROHISTIOCYTIC• FIBROUS HISTIOCYTOMA• DERMATOFIBROSARCOMA

PROTUBERANS• MALIGNANT FIBROUS HISTIOCYTOMA

SKELETAL MUSCLE• RHABDOMYOMA

• RHABDOMYOSARCOMA

SMOOTH MUSCLE• LEIOMYOMA

• LEIOMYOSARCOMA

VASCULAR • HEMANGIOMA

• LYMPHANGIOMA

• HEMANGIOENDOTHELIOMA

• HEMANGIOPERICYTOMA

• ANGIOSARCOMA

PERIPHERAL NERVE• NEUROFIBROMA

• SCHWANNOMA

• GRANULAR CELL TUMOR

• MALIGNANT (SCHWANNOMA)

UNCERTAIN• SYNOVIAL SARCOMA

• ALVEOLAR “SOFT PART” SARCOMA

• EPITHELIOD SARCOMA