PNS tumors

Question 1

PNS tumor where schwann cells are admixed with perineurial-like cells, fibroblasts, mast cells, and CD34+ spindle cells

Answer 1

Neurofibroma

Question 2

Small, nodular tumors arising from small cutaneous nerves that are rarely painful and do not cause neurologic deficits

Answer 2

Cutaneous/dermal neurofibroma

Question 3

Tumor presents as a large plaque-like elevation of skin in head and neck region. Associated with NF1.

Answer 3

Diffuse neurofibroma

Question 4

Neurofibroma type that resembles a bag of worms

Answer 4

Plexiform

Question 5

White-tan circumscribed mass in dermis with fusiform expansion and shredded carrot type collagen on histology. Moderately positive for S100 and Sox10, and highly positive for CD34.

Answer 5

Neurofibroma

Question 6

Inheritance of neurofibromatosis 1

Answer 6

Autosomal dominant

Question 7

Decreased IC neurofibromin protein and increased cascade RAS signaling in this hereditary syndroms

Answer 7

NF1

Question 8

Typically encapsulated benign nerve sheath tumor

Answer 8

Schwannoma

Question 9

Another name for neurofibrosarcoma

Answer 9

Malignant peripheral nerve sheath tumors (MPNST)

Question 10

WHO grading of MPNST

Answer 10

Grade III or IV based on presence of necrosis

Question 11

About 50% result from malignant transformation of a plexiform neurofibroma

Answer 11

MPNST

Question 12

Fleshy, variegated massed involving large peripheral nerve trunks. Histology shows multi-fascicular involvement, uniform spindle cells with hyperchromatic nuclei arranged in fascicles, enlarged nuclei, necrosis, and heterologous elements. Weak or patchy S100 and desmin expression.

Answer 12

MPNST

Question 13

Common age range for MPNST

Answer 13

20-50 yo

Question 14

Main clinical features of NF1

Answer 14

Multiple neurofibromas
Optic gliomas
Cafe-au-lait spots
Lisch nodules
Axillary freckling

Question 15

Main clinical features of NF2

Answer 15

Bilateral acoustic neuroma
Multiple meningiomas