PNS

A. NEOPLASM & METASTATIC

B. TRAUMA

C. INFECTION

D. CONGENITAL

(A) NEOPLASM

( 1 ) EPITHELIAL TUMORS

i. Papilomaii. Squamus Cell Carcinomaiii. Sinonasal Undifferenciated

Carcinomaiv. Adenocarcinoma v. Adenoid Cyst Carcinoma

( 2 ) NON EPITHELIAL TUMORS

i) Neuro Ecto-Dermal Tumourii ) Vasculariii) Soft Tissue Tumorsiv) Osseous and Cartilaginous Tumorsv) Hematologic Tumorsvi) Fibro-Osseous Diseasevii) Metastasis

PAPILLOMADefinitionBenign tumor of nasal cavity composed of vascular connective tissue covered by well-differentiated stratified squamous epithelium that tends to grow under and elevate mucosa (inverted).

Clinical Features ▬ Less common than allergic polyps; less than 3% in general

population. ▬ Most common in males aged 40–70 years. ▬ Unilateral from lateral sinus wall near ethmoids. ▬ Nasal stuffiness or obstruction. ▬ Secondary bacterial sinusitis. ▬ Postoperative recurrence 35–40%. ▬ May be associated with malignancy (about 10%).

Imaging Features

▬ Small to extensive mass ▬ Bone remodeling that may deviate, not cross nasal septum ▬ Mass may extend into ethmoid or maxillary sinuses ▬ T1-weighted MRI: low or intermediate ▬ T2-weighted MRI: infermediate to high, usually high ▬ T1-weighted post-Gd MRI: some contrast enhancement

(A/1/i ) Papiloma (Inverted)

50–80% of all malignant sinus masses. More than 60% originate in maxillary sinuses, followed

by nasal cavity, and ethmoid sinuses. Oral symptoms and signs may be initial; occasionally

considered an intraoral cancer clinically. SCC rarely arises from the ethmoid, frontal or sphenoid

sinus. Peak incidence is in the sixth and seventh decades,with

a male predominance (2:1). Occupational factors (including nickel, chromium,

thorotrast and radium exposure) are associated with an increased risk.

( A/1/ii ) Squamus Cell Carcinoma

Imaging Features Usually advanced when detected; bone destruction in 80%. Alveolar bone destruction reported in half of patients with

maxillary sinus carcinoma. ▬ Soft-tissue mass ▬ Bone radiolucency, secondary invasion of bone ▬ Border of bone destruction ill-defined ▬ Bone invasion frequent in gingival mandibular cancers,

generally considered to be about 50%,but up to 85% reported in upper jaw; maxillary sinus frequently involved

▬ Floating teeth; tooth resorption uncommon ▬ Advanced stage: pathologic fracture ▬ T1-weighted MRI: intermediate–low signal ▬ T2-weighted and STIR MRI: high signal ▬ T1-weighted MRI: contrast enhancement

SCC does not show specific MSCT or MRI characteristics. The main goal of imaging is to determine the submucosal extent of sinonasal neoplasms.

( A/1/iii )Sinonasal Undifferentiated Carcinomaand Neuroendocrine Carcinoma

SNUC is a malignant tumor with slight male predominance peak of incidence in the fifth and sixth decades. Short-time history of symptoms (mainly consisting of nasal

obstruction with epistaxys), largesize at presentation . high incidence of nodal metastases (15–20% of cases)

denote the aggressive nature of this neoplasm

( A/1/iv ) AdenocarcinomaAdenocarcinoma is a malignant neoplasm.more frequently observed in the ethmoid sinus.predilection for men in the fifth to seventh

decade.composed of epithelial cells, arranged in a

glandular or gland-like pattern. Occupational ITAC is strongly related to

softwood dust and leather dust inhalation

Imaging appearance ITAC may show a mixed solid–fluid pattern due to mucus

produced by tumoral cells . Mild discrimination occur between the lesion and

retained secretions (or mucocele) due to sinus blockage; meticulous attention should therefore be paid to the

presence of any solid component within a mucocele, combining the information provided by pre- and

postcontrast sequences and by diffusion-weighted sequences (when not degraded by artifacts).

A/1/V - Adenoid Cystic Carcinoma There are 450–750 minor salivary glands scattered in the whole head and neck

area, including sinonasal cavities. Adenoid cystic carcinoma (ACC) is a variant of adenocarcinoma arising from minor salivary glands.

IMAGING FINDINGS peculiar tendency of this tumor to grow submucosally and subperiosteally, thus

permeating bone and soft tissues. Invasion of muscles, vessels and fat tissue may be detected on imaging studies as

effacement and encasement with no or very limited mass effect. Similarly, replacement of spongiotic bone may occur with minimal changes of the

cortical bone; furthermore, tumor growth on both surfaces of a cortical bone (such as the posterolateral maxillary sinus wall) may be seen with only focal bone destruction.

findings are much better demonstrated on MRI, because of its high contrast resolution: plain SE T1 and 3D GE T1 with fat suppression are key sequences.

( 2 ) NON EPITHELIAL TUMORS

i) Neuro Ecto-Dermal Tumourii ) Vasculariii) Soft Tissue Tumorsiv) Osseous and Cartilaginous Tumorsv) Hematologic Tumorsvi) Fibro-Osseous Diseasevii) Metastasis

A/2/i - Neuro-Ectodermal Tumors

• Olfactory Neuroblastoma• Ewing Sarcoma and Peripheral Neuroectodermal

Tumor• Melanoma

Olfactory Neuroblastoma Esthesioneuroblastoma , is a rare malignant tumor (2% of all

sinonasal tumors) arising from the olfactory epithelium. normally found in the cribriform plate, the ethmoid roof, the

upper part of the nasal septum and the superior turbinates. on cross-sectional imaging ONB is often seen as a dumbbell-

shaped mass growing across the cribriform plate. MSCTshows the mass exhibits spontaneous hyperdensity

(reflecting high cellularity) and calcifications of variable size. MRI pattern is composed of intermediate T2 signal and T1

hypointensity; cystic areas may be found, capping the intracranial part of the

tumor. Both iodine and paramagnetic contrast enhancement is strong

sometimes making the differential diagnosis with vascular tumors is difficult.

a–c Olfactory neuroblastoma. A strongly enhancing mass with intermediate TSE T2 signal intensity originates from the left ethmoid roof and encases the superior turbinate (st).The mass is limited to the nasal cavity; the paranasal sinuses and the anterior cranial fossa are not invaded (Kadish stage A). Retained secretions are seen into the posterior ethmoid cells(asterisks)

Ewing Sarcoma and PeripheralNeuroectodermal Tumor

DefinitionMalignant tumor with rather uniform histologic appearance composed of densely packed, glycogen-rich small cells with round nuclei but without prominent nucleoli or distinct cytoplasmic outlines. Tumor tissue is typically divided into irregular strands or lobules by fibrous septa,but intercellular network of reticulin fibers, which is a feature of malignant lymphoma, is not seen. Mitoses are generally infrequent. Hemorrhage and extensive areas of necrosis are common (WHO).

Clinical Features

▬ Only 1–4% in head and neck area; most commonly mandible

▬ Hard swelling, pain or pain-free ▬ Males more frequent than females ▬ Usually first and second decades, but may occur at any age

Imaging Features

▬ Soft-tissue mass ‘▬ Moth-eaten’ bone destruction ▬ Bone production characteristic; periosteal ‘onion mskin’

reaction (usually in long bones), but not so typical in jaw

Ewing sarcoma, mandible; 24-year-old female with 10-year history of Ewing sarcoma treated with radiotherapy and chemotherapy, and a rather unchanged condition; now with pain and swelling and new soft-tissue mass,possibly due to infection.A Panoramic view shows bone production in entire half of mandible (arrow).B Axial CT image shows bone production both buccally and lingually (arrow)

arises from melanocytes that migrated during embryonal life from the neural crest to the mucosa investing the nasal cavity and sinuses.

nasal septum and lateral nasal wall are the most common sites of origin, and maxillary sinus is the most frequently involve.

Melanoma

Imaging studies, Appears as a solid soft tissue mass with local invasion

and relatively high tendency to nodal spread. A T1 spontaneous hyper intensity, atypical for nearly all

other benign and malignant sinonasal tumors, is much more requently exhibited by the melanotic variant;

(this is explained by the paramagnetic properties of melanin as well as by intralesional hemorrhage. ) Secondly, flow voids may be demonstrated on MRI

sequences at the periphery and into the lesion, representing its rich vascular network; such finding explains the frequent epistaxis occurring in patients

affected by melanoma

A/2/ii -Vascular Tumors

• Juvenile Angiofibroma• Lobular capillary hemangioma (LCH)• Angiomatous Polyp• Hemangiopericytoma (HPC)

Juvenile AngiofibromaJuvenile angiofibroma (JAF) is a highly vascular

mass characterized by three distinctive features:

exclusively in male adolescents; originathe posterior nasal fossa,close to the sphenopalatine foramen; it is composed of irregular vessels set in a

fibrous stroma . The typical clinical symptoms are nasal obstruction and epistaxistes.

Imaging Finding

JAF appears as a solid, brightly enhancing lesion vegetating in the posterior nasal cavity and nasopharynx and invading the pterygopalatine and infratemporal fossa;

A combination of TSE T2 and SE T1 (before and aftercontrast administration) is essential, for characterization of JAF, and the assessment of spongiotic bone invasion;

when JAF approaches the cavernous sinus, submillimetric 3d GE T1 sequences allow to define the relationships between the lesion

and vascular or nervous structures. The role of MSCT is restricted by the issue of radiation exposure and

by the lack of contrast resolution in grading medullary bone involvement; In selected cases, a volumetric data set acquired with MSCT is the basis for intraoperative navigation systems, which allow safer control of critical structures such as the internal carotid artery and the optic nerve.

14 year male, affected by juvenile angiofibroma. A large, intensely enhancing mass (b, c) occupies the left nasal fossa laterally displacing the nasal septum (arrowheads in a), nasopharynx and sphenoid sinuses. TSE T2 (a) shows several vascular flow voids into the lesion. Through an enlarged sphenopalatine foramen (arrows) the mass protrudes into the PPF. The lesion encroaches the ethmoid planum and sphenoid sinus roof, displacing the dura, appearing thickened and enhancing (arrows in b, c)

Lobular Capillary Hemangioma

Also referred to as pyogenic granuloma, is a benign vascular tumor composed of capillaries arranged in lobules into an edematous and fibroblastic stroma.

Arises from the anterior nasal septum, although skin and oral mucosa are the preferred head and neck sites of origin.

On MSCT, LCH appears as a soft tissue density mass that may cause bone remodeling and destruction;

MRI pattern consists of T2 hyperintensity and spontaneous T1 hypointensity. Bright enhancement is obtained after contrast agent JAF is the only differential diagnosis that can be readily ruled out, based on the typical site of origin, pattern of growth, age and sex of the patient.

23 year male. A large mass with hyper TSE T2 signal (a) and bright contrast enhancement (b, c) fills the ethmoid cells and protrudes into the frontal sinus (arrowhead). The sharp interface between the lesion and both the orbital and intracranial content (arrows) indicates low aggressiveness. Pathologic examination of the surgical specimen revealed lobular capillary hemangioma

Angiomatous Polyp

It is a sinochoanal polyp whose vascular pedicle is strangled by the pressure exerted by the bony walls of the foramen through which it exits sinus cavity of origin to reach the nasal cavity.

Such compression may trigger a cascade of dilatation and stasis of feeder vessels, necrosis (which in some cases prevails) and neovascularization.

The site and pattern of growth of the lesion as well as its mixed appearance (fluid-like intensity/density of the sinusal component, intense enhancement of its vascular compromised portion) are sufficient clues for the diagnosis on imaging studies.

a, b 26 year female. Post contrast SE T1 shows an antrochoanal polyp. The vascular compromised part of the lesion, strangled as it courses through an accessory ostium (arrows), is referred to as angiomatous polyp.

Hemangiopericytoma Hemangiopericytoma (HPC) is a vascular tumor

that can either be benign or malignant and may be found in any part of the body; 15–20% of cases arise from the head and neck, 5% in the sinonasal region. HPC originates from pericytes, mesenchymal cells covering the outer surface of capillaries, implied in flow regulation and vasoconstriction.

Interestingly, four cases ofoncogenic osteomalacia (a rare condition manifesting with muscle weakness, bone pain and frailty)

On both MSCT and MRI, HPC appears as an indistinct soft tissue mass with moderate to bright contrast enhancement; bone changes (remodeling,

destruction) are generally also found. Lesions arising in the sinonasal tract do not show aggressive behavior, distant metastases are rare.

A/2/iii – soft tissue tomors

• Peripheral Nerve Sheath Tumor• Nasal Glioma• Meningioma• Rhabdomyosarcoma

Peripheral Nerve Sheath Tumor

generally benign in nature. Schwannoma more commonly affects the ethmoid

followed by the nasal septum and maxillary sinus, usually as a solitary lesion.

Neurofibroma is classically described as localized, diffuse and plexiform.( Rarely malignant transformation spindle cell sarcoma).

Triton tumor is a neoplasm composed of peripheral nerve fibers and well-differentiated striated muscle fibers, described as either benign or malignant

SchwannomaDefinitionBenign nerve sheath tumor emanating from Schwann cells. (The terminology is confusing. Thefollowing terms have been used for the same tumor: schwannoma, neuroma, neurinoma, neurolemmoma, perineural fibroblastoma.)Clinical Features

▬ Asymptomatic mass. ▬ About 13% of schwannomas are found in head and neck, most in the lateral cervical region. ▬ Almost half of oral schwannomas reported to occur in the tongue.

Imaging Features ▬ Well-defined homogeneous soft-tissue mass, enhancement, but variable appearance because

of cystic and solid components. Schwannoma is often cystic, as opposed to neuroma, which is seldom cystic.

▬ Enlarged foramina. ▬ Atrophy of muscles. ▬ Associated with neurofibromatosis. ▬ T1-weighted MRI: isointense with muscle. ▬ T2-weighted MRI: hyperintense, homogeneous, both cystic and solid components, or

heterogeneous. ▬ T1-weighted post-Gd MRI: cystic nature with rim enhancement.

Nasal Glioma Nasal glioma is a congenital fronto-nasal mass composed of

dysplastic neuroglial tissue and fibrovascular tissue. This mass is thought of as a cephalocele that lost connection to the

skull base. It is found at birth or during infancy as a subcutaneous lesion located on the nasal dorsum, typically at the glabella,,on the midline (although this is not the rule)

MRI should be considered the imaging technique of choice, because its low invasiveness and better depicts the absence of connections with the brain;

the lesion displays hypointense T1 signal (as compared to gray matter) and T2 hyperintensity (due to gliosis); no contrast enhancement is expected.

Meningioma Meningioma may be found in the sinonasal cavities in four different

forms: as the direct extension of a lesion arising in anterior cranial fossa; as a metastasis of an intracranial meningioma; as an extracranial neoplasm arising from arachnoid cells located in the sheath

surrounding cranial nerves in their course through skull base foramina; as an extracranial lesion with no connection with the anterior cranial fossa .

The nasal cavity is the most common site of sinonasal meningiomas. MSCT density is generally homogeneous, MRI signal is iso- to

hyperintense on T2 sequences and iso- to hypointense on T1, compared with gray matter; contrast enhancement is bright. Bone erosion, sclerosis and hyperostosis may be found.

Rhabdomyosarcoma

Rhabdomyosarcoma is the most common sinonasal malignant tumor in children,

characteristic are aggressive local behavior and early metastases. Three subtypes (embryonal, alveolar and pleomorphic) are described, however the differentiation may be difficultat histology.

As the nasal symptoms produced by this tumor are similar to allergic or infectious diseases, at the time of diagnosis rhabdomyosarcoma is often a large mass invading adjacent structures.

On MRI, TSE T2 signal is hyperintense to muscle. Contrast enhancement is heterogeneous; necrosis,

calcifications and hemorrhage are rare (Hagiwara et al. 2001).

A/2/iv - Osseous and Cartilaginous Tumors

• Osteosarcoma• Chondrosarcoma• Ameloblastoma

OsteosarcomaSynonym: Osteogenic sarcomaDefinitionMalignant tumor characterized by direct formation of bone or osteoid by tumor cells (WHO).Clinical Features

▬ Most common primary malignancy in skeleton (apart from myeloma), usually in bones around the knee and primarily in children and adolescents; pain common

▬ Only 5–10% in head and neck; mostly in jaws ▬ Usually painless swelling in jaws,but also pain and mental nerve paresthesia ▬ Mandible slight predominance ▬ Males slight predominance ▬ May occur in any age group; peak in fourth decade ▬ Jaw osteosarcomas have tendency to occur in older patients than osteosarcomas in

other bones and less likely to metastasize ▬ However, prognosis of jaw sarcoma is poor and does not seem to have improved

with chemotherapy in a similar way to sarcomas in other bones

Imaging Features ▬ Soft-tissue mass, may grow aggressively and rapidly ▬ Radiolucent or most frequently, a combination of radiolucent

and radiopaque appearance; bone production may be extensive ▬ Border of bone destruction ill-defined ▬ Bone production may typically have ‘sunburst’ appearance, best

seen on CT images ▬ T1-weighted MRI: heterogeneous (intermediate–low) signal ▬ T2-weighted and STIR MRI: heterogeneous signal (variable high

to intermediate–low) epending on bone production and cellular content

▬ T1-weighted post-Gd MRI: heterogeneous (intense to low) contrast enhancement

Chondrosarcoma Chondrosarcoma generally affects long bones, ribs and pelvis; 60% of cases occurring in the alveolar process of the maxilla, although several

cases of nasal septal chondrosarcoma are reported. Sinonasal chondrosarcoma tend to be high grade lesions,.

Imaging feature

MSCT appearance consists of a soft tissue matrix with scattered calcifications (which may represent a helpful hint for the differential diagnosis) and bone destruction.

On MRI, chondrosarcoma exhibits bright T2 signal and T1 hypointensity with variable, heterogeneous contrats enlacement .

Typically, scalloped margins and intralesional septa display enhancement, resulting in a peculiar rings and arcs pattern.

Although calcifications are less evident than on MSCT, the T2 hyperintensity (uncommon for neoplasms) and pattern of enhancement may suggest chondrosarcoma on MRI.

Ameloblastoma benign but locally aggressive neoplasm originate from remnants of the odontogenic epithelium,

from the lining of odontogenic cysts or from the basal membrane of the overlying oral mucosa.

The mandible and maxilla as common site of origin (80 vs. 15–20% of cases),

fifth and sixth vs. second and third decade to show more aggressive behavior than those originating

from the jaw.

Imaging feature

On cross-sectional imaging, appear as a uni- or multilocular cystic and solid lesion arising from the alveolar ridge.

Bone remodeling and destruction are often seen, along with maxillary sinus and nasal cavity invasion.

A peripheral (generally incomplete) bony shell may surround the lesion; the presence of multiple septa within the lesion may result in a honeycomb appearance;

In 10% of cases a dental element may be embedded into the lesion . MRI appearance of plexiform ameloblastoma may be similar to the

columnar pattern of inverted papilloma: this is due to the presence of thin septa and papillary projections of solid tissue within the lesion, both enhancing after contrast administration

a–c 73 year male. The left maxillary sinus is occupied by a mass protruding in the nasal fossa. Although the upper part of the mass (arrows) shows a columnar pattern resembling inverted papilloma, the destruction of the posterolateral sinus wall (b) indicates a more aggressive pattern of growth. Involvement of the alveolar process of maxillary bone (arrowheads)suggests odontogenic origin. Pathology proved the lesion to be ameloblastoma

A/2/V - Hematologic Tumors

• Lymphoma• Granulocytic Sarcoma• Plasmacytoma• Fibro-Osseous Disease• Metastasis

Non-Hodgkin’s LymphomaDefinitionMalignant neoplasm of cells from the lymphatic system.Clinical Features

▬ Lymph node disease most common ▬ Non-Hodgkin’s lymphoma of involves extranodal sites (as

opposed to Hodgkin’s lymphoma which is predominantly nodal)

▬ Extranodal involvement may include maxillary sinus and maxilla or, less frequently, mandible

▬ All age groups, adults in particular (except Burkitt’s lymphoma)

▬ Burkitt’s lymphoma was initially described as African jaw lymphoma; affects children; shows rapid growth and may involve one or both jaws

Imaging Features

▬ Soft-tissue mass ▬ Radiolucency ▬ Border of bone destruction ill-defined ▬ Non-Hodgkin’s lymphoma, and rarely Hodkin’s lymphoma, may

present with necrofic lymph nodes ▬ However, it is not possible to definitely distinguish between non-

Hodgkin’s,Hodgkin’s and metastatic lymph nodes based on CT and MRI

▬ T1-weighted MRI: intermediate–low signal ▬ T2-weighted and STIR MRI: intermediate signal ▬ T1-weighted MRI: contrast enhancement

37 year male. NK/T-cell lymphoma. TSE T2(a) shows destruction of thenasal septum and bulbous partof the inferior turbinates; afocal erosion of the palate(arrow) is demonstrated onpostcontrast VIBE (b)

Also known as chloroma, granulocytic sarcoma is a rare tumor composed of precursors of the granulocyte series, including myeloblasts, promyelocytes and myelocytes.

develop during the course of, or as a presenting sign of a variety of myeloproliferative disorders among which is acute myelogenous leukemia; seldom, granulocytic sarcoma may even precede leukemia by weeks or months.

Although more commonly described in the orbit (actually it was first described as a green ocular tumor hence the

name chloroma), Imaging shows a homogeneously enhancing soft tissue mass.

Granulocytic Sarcoma

Plasmacytoma is a soft tissue mass composed of monoclonal plasma cells.

most commonly affecting the sinonasal cavities, followed by the nasopharynx and oropharynx, and manifesting in 90% of cases as a solitary mass .

15–20% of plasmacytomas convert into multiple myeloma, although such transformation is thought to occur in intramedullary lesions, whereas extramedullary lesions (such as sinonasal plasmacytoma) are generally solitary lesions.

Imaging findings (soft tissue mass, bone destruction) are completely nonspecific

Plasmacytoma

Fibrous DysplasiaDefinitionGenetically based sporadic disease of bone that may affect single or multiple bones monostotic or polyostotic). Fibrous dysplasia occurring in multiple adjacent craniofacial bones is regarded as monostotic (craniofacial fibrous dysplasia).May be part of the McCune-Albright syndrome (WHO). Non-neoplastic, self-limiting but non-capsulated lesion occurring mainly in young subjects, showing replacement of normal bone by cellular tissue containing islands or trabeculae of metaplastic bone.Clinical Features

▬ Monostotic most common (70–80%, femur, ribs) ▬ Craniofacial bones up to 25% of monostotic forms ▬ Maxilla, lateral region in particular,more frequent than mandible ▬ Painless swelling, jaw asymmetry ▬ Second and third decades ▬ No sex predilection ▬ McCune-Albright syndrome; polyostotic

Imaging Features

▬ Radiolucency ▬ Mixture of radiolucency and radiopacity ▬ Radiopacity; ground-glass appearance ▬ Unilocular or multilocular ▬ Border poorly defined; blend into normal bone, but may be more

well defined (and thus difficult to distinguish from ossifying fibroma; same histopathology)

▬ Usually expanded bone ▬ May displace teeth, walls of nasal cavity, paranasal sinuses, orbits ▬ Mandibular canal may be displaced cranially ▬ Tooth resorption rare ▬ T1-weighted MRI: intermediate signal ▬ T2-weighted MRI and STIR: heterogeneous low signal ▬ T1-weighted MRI: contrast enhancement

Fibrous dysplasia and ossifying fibroma share overlapping histologic features, making the differential diagnosis challenging, particularly when biopsy does not achieve an adequate sample. Some imaging findings may be helpful for the characterization of the lesion (Fig. 23).

Metastasis Rarely, the nose and Paranasal sinus are the site of a distant

metastasis, mostly of renal cell, breast or lung carcinoma. Signs and symptoms are similar to those caused by benign

and malignant lesions. Imaging appearance is nonspecific, although intense

enhancement is expected in hypervascular metastases, such as those produced by renal cell carcinoma and melanoma.

Maxillary sinus (33%) is the most commonly involved site followed by sphenoid sinus (22%), ethmoid (14%) and frontal sinus (9%); simultaneous involvement of more than one cavity occurs in as many as 22% of cases.

TRAUMACT is the superior imaging modality to assess bone structures and routinely the examination will include axial and coronal sections.With multidetector CT, high-quality images can be obtained in any desired plane and 3D reconstruction can be very valuable in the evaluation of the complex facial skeleton.

The buttress system of the midface. The buttress system of the midface is formed by the strong frontal, maxillary, zygomatic, and sphenoid bones and their attachments to one another.The central midface consists of several fragile bones that easily ‘‘crumple’’ when subjected to strong forces. These more fragile bones are surrounded by the thicker bones of the buttress system, which provide structure and absorb the forces applied to the face. Most of the forces absorbed by the face are masticatory, therefore the vertical buttresses are the most well developed. These include the medial nasomaxillary buttress and the lateral zygomaticomaxillary buttress. Three horizontal buttresses interconnect and provide support for the vertical buttresses: the frontal bone and supraorbital rims (frontal bar), the nasal bones and inferior orbital rims, and the maxillary alveolus. (From Linnau KF, Stanley RB Jr, Hallam DK, et al. Imaging of high-energy midfacial trauma: what the surgeon needs to know. Eur J Radiol 2003;48:17–32;with permission.)

Fractures

Clinical Features

▬ See Non-fracture Traumas ▬ Abnormal morphology such as

flattening ▬ Palpable step-off of bone ▬ Crepitation due to emphysema ▬ Paresthesia, anesthesia ▬ Hemorrhage

Imaging Features ▬ See Non-fracture Traumas ▬ Cortical discontinuity, defect ▬ Abnormal angulation ▬ Absent or displaced bone ▬ Abnormal linear density ▬ Bone overlap (“double

radiopacity”) ▬ Green-stick in young patients “▬ Empty fossa” sign on axial CT

images ▬ Localized air collection

DefinitionTraumatic cortical discontinuity with or without dislocation

LeFort FracturesDefinitionLeFort 1 is characterized by fracture just above the floor of the nasal cavity with separation of the entire palate and maxillary alveolar process; fractures through the lower nasal septum, lower walls of maxillary sinuses, and lower pterygoid plates (“horizontal fracture”). “Floating palate” (LeFort 1)

Characterized by fracture of the root of the nose, bilateral fractures of the lacrimal bones and medial orbital walls, the floor of the orbits near

the infraorbital canals, zygomaticomaxillary sutures and anterior walls of maxilla (“pyramidal fracture”) and posteriorly, infratemporal surfaces of

the maxilla and lower pterygoid plates. Wassmund 1 fracture does not include the nasal bones but is otherwise

identical.“Dish face”, hemorrhage, edema, emphysema, and in near 80%

anesthesia of infraorbital nerve(s) (LeFort 2)

LeFort 2

characterized by separation of the entire viscerocranium from the skull base (“craniofacial dysjunction”); fracture of the root

of the nose, bilateral fractures of the lacrimal bones and medial orbital walls, the floor of the orbits to the inferior

orbital fissure,where one fracture line extends to the lateral orbital wall and another down across the posterior maxilla to the lower pterygoid plates and additionally, fractures of the

zygomatic arches. Wassmund 3 fracture does not include the nasal bones but is otherwise identical.

“Dish face”, CSF rhinorrhea, hemorrhage, edema, emphysema, damage to lacrimal apparatus, and in near 70%

anesthesia of infraorbital nerve(s) (LeFort 3)

LeFort 3

Tripod FractureSynonyms: Trimalar or zygomatic fracture

DefinitionFracture through (1) lateral orbital wall with fracture site at zygomaticofrontal suture, (2) zygoma and maxilla with fracture site at zygomaticomaxillary suture, (3) zygomatic arch with fracture site at zygomaticotemporal suture.

Clinical Features ▬ Most common fracture of facial skeleton after nasal and mandibular

fractures ▬ About half of all midfacial fractures (more than two-thirds in one

study), either alone or in combination with other midfacial fractures ▬ Infraorbital nerve paresthesia or anesthesia in almost 95%

Blow-out FractureDefinitionFracture of orbital floor, usually not orbital rim (classic); but also of medial or other orbital walls.Clinical Features

▬ Only 3–5% of all midfacial fractures ▬ Diplopia ▬ Enophthalmos, exophthalmos

Acute RhinosinusitisDefinitionAcute inflammation in nose and paranasal sinuses.

Clinical Features ▬ One of most common medical afflictions. ▬ Viral rhinosinusitis most common (common cold, influenza). ▬ Bacterial rhinosinusitis may develop secondarily (Haemophilus

influenzae, Streptococcus pneumoniae). ▬ Pain over sinuses; cheek, frontal, between eyes, or suboccipital. ▬ Toothache, teeth tenderness to percussion; more than one tooth of

maxillary lateral segment(s). ▬ Headache seldom. ▬ Dental etiology in 10–20%; larger frequencies have been reported

depending on patient materials.

Imaging Features

▬ Nodular or smooth mucosal thickening or complete sinus opacification

▬ Contrast-enhanced inflamed mucosa lining; variable amounts of submucosal edema and surface secretions

▬ Air-fluid level, most frequent in maxillary sinus, due to bacterial sinusitis with obstruction of ostium, but only in 25–50% of patients with this disease

▬ T1-weighted MRI: low to intermediate ▬ T2-weighted MRI: high signal of inflamed mucosa and

fluid ▬ T1-weighted post-Gd MRI: intense enhancement of

inflamed mucosa; no enhancement of fluid

Chronic SinusitisDefinitionDevelops from either persistent acute inflammationor repeated episodes of acute or subacute sinusitis.

▬ Allergic sinusitis ▬ Vasomotor rhinitis ▬ Fungal sinusitis (90% Aspergillus fumigatus; may

be fulminant and invasive in immunosuppressedpatients)Clinical Features

▬ Anaerobic microorganisms frequently isolated

Imaging Features

▬ Varying mucosal swelling, smooth or irregular swelling due to edema and secretion.

▬ Thickened, sclerotic, fibrotic sinus walls, particularly of maxillary sinuses.

▬ Dystrophic calcification. ▬ T1-weighted MRI: low to intermediate. ▬ T2-weighted MRI: usually high signal of inflamed mucosa, low signal

of sclerosis and fibrosis. Inspissated mucus can be dark on all sequences resulting in false-negative MR diagnosis of chronic sinusitis

Mucosal Imaging Findings in Asymptomatic Individuals

MRI findings of paranasal sinuses in patients with brain imaging. ▬ Mucosal thickening up to 3 mm may be present in clinically normal

individuals. ▬ Clinically silent focal areas of mucosal thickening occur from about

one-fourth and up to two-thirds of asymptomatic individuals.

Retention Cysts,Mucous and Serous

DefinitionMucous retention cyst: obstruction of submucosal mucinous gland, thus cyst wall of duct epithelium and gland capsule. Serous retention cyst: accumulation of serous fluid in submucosal layer of sinus mucosa, thus cyst lining of elevated mucosa.

Imaging Features

▬ Smooth, spherical soft tissue mass. ▬ Retention cysts found incidentally in 10–35% of patients,

most commonly in maxillary sinus, butcan occur in any sinus.

▬ Frequently small, may become large but alwayssome air.

▬ Almost in every case normal bone. ▬ T1-weighted MRI: usually low to intermediate signal, but may

show high signal if cyst has highprotein content.

▬ T2-weighted MRI: high signal

PolypsDefinitionExpansion of fluids in deeper lamina propria of Schneiderian mucosa in nasal fossa and paranasal sinuses.Clinical Features

▬ Most common expansile condition in nasal cavity; about 4% in general population. ▬ Nasal polyps most often associated with allergy, and frequently multiple and symmetric, but

may result from infectious rhinosinusitis, vasomotor rhinitis, cystic fibrosis, diabetes mellitus, aspirin intolerance, and nickel exposure.

▬ In patients with polyps up to about 70% with asthma. ▬ Nasal stuffiness. ▬ When seen in children, cystic fibrosis should be ruled out.

Imaging Features ▬ Smooth, spherical soft tissue mass ▬ If multiple, complete opacification of nasal cavity and sinuses ▬ T1-weighted MRI: low to intermediate signal ▬ T2-weighted MRI: high signal ▬ Heterogeneous MR signal characteristic in chronic polyps; can also enhance

MucocelesDefinitionCollection of mucoid secretions surrounded by mucus-secreting respiratory epithelium.Both retention and mucocele cysts consist of mucous secretions surrounded by epithelial lining, but are distinguished by their clinical and imaging features.Mucocele develops due to obstruction of sinus ostium or a compartment of a sinus with the sinus mucosa as the mucocele wall and always with expandedsinus walls.

Clinical Features ▬ Most common expansile condition in paranasal sinuses. ▬ Most frequent in frontal sinuses (60–65%); only 5–10% in sphenoid as well as

in maxillary sinuses. ▬ Both sexes,wide range of age: 20 to 60 years. ▬ Classic mucocele is sterile with signs and symptoms from mass effect. ▬ Pain uncommon. ▬ If infected, pain; mucopyocele or pyocele. ▬ Ostial obstruction may be caused by inflammatory scar, trauma, or tumor.

Imaging Features

▬ Initially, intact but remodeled, expanded surrounding bone.

▬ With progressive growth sinus wall will be destroyed. ▬ Completely airless sinus. ▬ T1-weighted and T2-weighted MRI: variable MR signals

depending on protein content, state of dehydration, and viscosity of content; most frequently observed patterns are moderate-to-marked high signal on T1 and T2, or moderate-to-markedlow signal on T1 and T2, usually low to intermediate T1 and high T2.

▬ T1-weighted post-Gd MRI: no enhancement except of thin peripheral rim.