Neuropathology Review Questions

11/30/12

Match the tumor with the description

• Neurofibroma• Schwannoma• Both• Neither

1. Antoni A areas2. Antoni B areas3. Verocay bodies4. Axons present between tumor

cells5. Plexiform type strongly

associated with NF1

SchwannomaSchwannoma

Neurofibroma

Schwannoma

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

– 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– 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

• 12-24h• 1-2d• 5-7d• 10-20d• >3mo

1. Lipid laden macrophages first appear

2. Fibrillary astrocytes at periphery3. Gemistocytic astrocytes at

periphery4. Polymorphonuclear infiltrate5. Neuronal necrosis first apparent

5-7d

>3mo

12-24h

10-20d1-2d

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