ABPath Neuropathology 1 — Questions and Answers
Question 1: Which histologic feature is MOST characteristic of glioblastoma multiforme (GBM)?
- Rosenthal fibers
- Pseudopalisading necrosis (Correct answer)
- Homer Wright rosettes
- Verocay bodies
Correct answer: Pseudopalisading necrosis
Pseudopalisading necrosis, where tumor cells line up around areas of necrosis, is the hallmark histologic feature of GBM (WHO Grade IV astrocytoma).
Question 2: A 10-year-old presents with a cerebellar mass; biopsy shows a biphasic pattern with compact Rosenthal fiber-rich areas and loose microcystic areas. What is the most likely diagnosis?
- Medulloblastoma
- Ependymoma
- Pilocytic astrocytoma (Correct answer)
- Diffuse intrinsic pontine glioma
Correct answer: Pilocytic astrocytoma
Pilocytic astrocytoma is a WHO Grade I tumor with a classic biphasic pattern of compact bipolar cells with Rosenthal fibers and loose areas with eosinophilic granular bodies.
Question 3: Which immunohistochemical marker is MOST useful for distinguishing meningioma from other CNS tumors?
- GFAP
- Synaptophysin
- EMA (Correct answer)
- S-100
Correct answer: EMA
EMA (epithelial membrane antigen) is characteristically expressed in meningiomas and helps differentiate them from glial tumors that express GFAP.
Question 4: Lewy bodies, the pathologic hallmark of Parkinson disease, are composed primarily of which protein?
- Tau
- Alpha-synuclein (Correct answer)
- TDP-43
- Amyloid beta
Correct answer: Alpha-synuclein
Lewy bodies are intracytoplasmic inclusions composed primarily of aggregated alpha-synuclein protein, also seen in Lewy body dementia.
Question 5: Which variant of medulloblastoma carries the BEST prognosis according to WHO 2021 classification?
- Large cell/anaplastic
- Classic
- Desmoplastic/nodular
- WNT-activated (Correct answer)
Correct answer: WNT-activated
WNT-activated medulloblastoma has a >95% 5-year survival rate, making it the most favorable molecular subgroup of medulloblastoma.
Question 6: Neurofibrillary tangles seen in Alzheimer disease are composed primarily of which protein?
- Alpha-synuclein
- Prion protein
- Hyperphosphorylated tau (Correct answer)
- Ubiquitin
Correct answer: Hyperphosphorylated tau
Neurofibrillary tangles consist of paired helical filaments made of hyperphosphorylated tau protein that accumulates intraneuronally in Alzheimer disease.
ABPath Neuropathology 1
Which histologic feature is MOST characteristic of glioblastoma multiforme (GBM)?