Pop Quiz #99

The correct answer is D. S-100.

Granular cell tumors are benign growths which typically occur on the tongue. They are typically well-circumscribed, raised, firm nodules. Histologically, the cells have uniform nuclear characteristics and granular cytoplasm due to presence of lysozyme. These tumors are PAS positive and S-100 positive.

CD31 stains positive in vascular neoplasms (e.g. angiosarcoma). Synaptophysin stains positive in neuroendocrine neoplasms (e.g. Merkel cell carcinoma). Factor XIIIa stains positive in dermatofibroma, xanthoma disseminatum, fibrous papule, atypical fibroxanthoma, and xanthogranuloma. CD34 stains positive in vascular tumors (benign/malignant), dermatofibrosarcoma protuberans, neurofibroma, epithelioid sarcoma, spindle cell lipoma, and fibrous papule.


Ferreira JC et al. Granular cell tumor mimicking a squamous cell carcinoma of the tongue: a case report. BMC Res Notes. 2017 Jan 3;10(1):14. PubMed Link: https://www.ncbi.nlm.nih.gov/pubmed/28057062.

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