A biopsy from a posterosuperior nasal cavity polypoidal lesion shows a trabecular/ribbon-like pattern with hyperchromatic nuclei, salt-and-pepper chromatin, and positive synaptophysin and chromogranin staining. The diagnosis is:
- A Sinonasal undifferentiated carcinoma (SNUC)
- B Sinonasal neuroendocrine carcinoma ✓
- C Olfactory neuroblastoma
- D Melanoma
Correct answer: B. Sinonasal neuroendocrine carcinoma
Explanation
Sinonasal neuroendocrine carcinoma (SNEC) is a malignant tumour with neuroendocrine differentiation confirmed by immunohistochemistry (synaptophysin+, chromogranin+, NSE+) and shows a trabecular or ribbon-like architectural pattern. It is distinguished from olfactory neuroblastoma by: absence of neural stroma, higher mitotic rate, necrosis, positive CK (cytokeratin) staining, and INSM1 positivity in some. Unlike SNUC, there is definite neuroendocrine differentiation. Treatment is combined surgery and chemoradiation.
Reference: Dhingra Diseases of Ear, Nose and Throat, 7th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.