Case 118
- Wangpan Shi
- May 24
- 1 min read
A 43-year-old male with a left ear intra-labyrinthine mass:





What's the morphology diagnosis?
A: Meningioma
B: Solitary fibrous tumor
C: Schwannoma
D: Neurofibroma
E: MPNST
F: Neuroblastoma
Answer
The correct answer is C. There is focal area of Antoni-B hypocellular area; However, the morphology is a little bit unusual for a classic schwannoma more of the described epithelioid or round cell morphology.
Immunohistochemical staining shows the tumor to be positive for SOX10, INI1 (retained), and INSM1 (subset), while negative for synaptophysin, pankeratin (AE1/AE3 + CAM5.2 + MNF116), and SSTR2A, consistent with schwannoma. SOX10 and INI1 stains were also repeated on block B1 to confirm tumor involvement.
Case credit: UCSD Pathology
Author: Wangpan Jackson Shi, MD
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