Neuropathology Review Questions 11/30/12

Match the tumor with the description Antoni A areas Antoni B areas Verocay bodies Axons present between tumor cells Plexiform type strongly associated with NF1 Schwannoma Neurofibroma Schwannoma Both Neither Schwannoma Schwannoma Neurofibroma Neurofibroma

Schwannoma Neoplastic schwann cells in two basic patterns Antoni A Compact Spindle cells Collagen abundant Antoni B Loose Stellate round cells Microcysts

Schwannoma Verocay bodies In Antoni A areas Anuclear areas with palisading cells

Schwannoma Benign No sex predominance Mean age 40-50 years Occasionally multiple With NF2 or schwannomatosis Neural crest origin Frequently affect sensory nerves May be cystic, hemorrhagic S100 positive

Schwannoma Intracranial Spinal Head & Neck Posterior mediastinum Superior vestibular nerve Internal acoustic meatus at root entry zone Trigeminal nerve Middle fossa, posterior fossa or both Spinal Intraspinal or dumbell shaped Head & Neck Posterior mediastinum Retroperitoneum Flexor surfaces of extremities

Neurofibroma Peripheral nerve sheath tumor Mix of Schwann cells, perineural cells, fibroblasts Hypocellular with mucoid matrix Collagen bundles follow nerve fibers Entrapped axons, ganglion cells Tactilelike structures Resemble Meissnerian corpuscles

Neurofibroma Any age No sex predominance Not intracranial Solitary cutaneous nodules From small terminal nerves Potential for malignant transformation

Neurofibroma Types Cutaneous Intraneural Painless, unencapsulated Solitary, low malignant potential Multiple = NF1 Intraneural Large nerve trunks NF1 (plexiform = pathognomonic for NF1) “bag of worms” Malignant potential

Schwannoma Neurofibroma Extremities Trunk Eccentric to nerve Incorporates nerve Globular Globular, fusiform or diffuse Encapsulated No capsule Tan-yellow, opaque Gray-tan, opalescent Occasionally cystic Non-cystic Highly cellular Low-moderate cellularity Antoni A/B Uniphasic pattern Axons absent Axons present Schwann cells Multiple cells No mast cells Mast cells present Rare malignancy Malignant potential NF2 association NF1 assosciation

Match the time period after an infarct with the histologic appearance Lipid laden macrophages first appear Fibrillary astrocytes at periphery Gemistocytic astrocytes at periphery Polymorphonuclear infiltrate Neuronal necrosis first apparent 12-24h 1-2d 5-7d 10-20d >3mo 5-7d >3mo 10-20d 1-2d 12-24h

Infarction 12-24 hours Ischemic neuronal necrosis Possibly as little as one hour Softening & discoloration Circumscribed pallor

Infarction 1-2 days: PMN infiltration 2-5 days: Astrocyte retraction balls, BBB breakdown, edema 5 days: Macrophages (gitter cells), neovascularization 2 weeks: Gemistocytic astrocytes 3 months: Fibrillary astrocytes, preservation of outer cortical layer

Infarct