Masticator Space

Question 1

Pterygoid Venous Plexus Asymmetry

Answer 1

1. Unilateral (L > R) prominence of deep facial venous network
2. Draining cavernous sinus through ovale, spinosum, lacerum. Connects w/ ophthalmic veins through inferior orbital fissure, deep branch of anterior facial vein
3. Drainage 1: maxillary vein –> retromandibular vein –> IJV. Drainage 2: Posterior and common facial veins –> IJV
4. Can be confused with perineural tumor spread, carotid cavernous fistula, venous vascular malformation

Question 2

Benign Masticator Muscle Hypertrophy

Answer 2

1. Unilateral or bilateral enlarged masticators
2. Normal density and enhancement of muscle
3. Preserved fat planes
4. May see cortical thickening mandible or zygoma

Question 3

CN-V3 Denervation

Answer 3

1. Acute denervation –> T2 hyperintense edema, enhancement (eventual fatty replacement)
2. Masticator muscles, tensor veli palatini (Eustachian tube dysfunction), and anterior belly digastric and mylohyoid muscles
3. Look for cause of denervation (schwannoma, perineural ACCa, etc)

Question 4

Masticator Space Abscess

Answer 4

1. Typical source 2nd or 3rd mandibular molar periapical or extraction socket
2. Look for osteomyelitis of posterior body/ramus of mandible (cortical destruction, periosteal reaction)
3. May see ICA spasms

Question 5

Masticator Muscle Atrophy

Answer 5

1. Chronic = fatty infiltration, volume loss
2. Look for culprit lesion along course of CNV3
3. Review history for trauma/surgery. If none, need to rule out malignancy. Look for perineural tumor.

Question 6

CNV3 Schwannoma

Answer 6

1. Well-circumscribed (b/c encapsulated)
2. Smooth enlarged of bony foramen (NOT erosion)
3. Intramural cysts are classic (usually homo enhancement, but hetero with cysts)
4. If fast growing, think sarcoma

Question 7

CNV3 Perineural Tumor

Answer 7

1. Enhancing enlarged nerve, loss of normal fat
2. May see nerve enlargement, enlarged osseous foramen mimicking schwannoma
3. Look carefully at primary (including skin, and parotid along auriculotemporal nerve)
4. Can have “skip lesions” along nerve

Question 8

Chondrosarcoma, Masticator Space

Answer 8

1. Characteristic, pronounced T2 hyper intensity of chondroid tumors
2. Generally hetero, intense enhancement.
3. Rings and Arcs calcs on CT inside of soft tissue mass
4. At TMJ, can look exactly like synovial chondromatosis (but both are surgical treatment, path can tell difference)

Question 9

Sarcoma, Masticator Space

Answer 9

1. Solid, expansile, destructive, aggressive looking mass
2. Nonspecific; not possible to differentiate most types of sarcomas unless osteosarc or chrondrosarc matrix present. However, bone production or calcification can be present in any sarcoma
3. Perineural tumor spread can be seen