Objectives: Published cases of oral high-grade neuroendocrine carcinoma (HGNEC) variably call the tumors Merkel cell carcinoma (MCC) or small-cell/high-grade neuroendocrine carcinoma. We studied cases of cutaneous MCC and mucosal HGNEC to better distinguish them and to better define oral cases. Study design: Twelve cutaneous MCC and 14 mucosal HGNEC cases were identified. We reviewed the hematoxylin-eosin (H&E) morphology and performed immunohistochemistry for cytokeratin 20 (CK20), thyroid transcription factor 1 (TTF-1), p63, neurofilament (NF), and achaete-scute homolog 1 (MASH-1). We also performed polymerase chain reaction (PCR) for the Merkel cell polyomavirus (MCPyV). Results: By morphology and immunohistochemistry, MCC and HGNEC showed many differences. CK20, NF, and TTF-1 stains were the most discriminatory. MASH-1 was expressed by both MCC and HGNEC. MCPyV was present in MCC and absent in all HGNEC. The 2 oral cavity mucosal carcinomas segregated into MCC and HGNEC types, the former having the H&E nuclear morphology and classic dot-like perinuclear CK20 staining typically associated with MCC. Conclusions: Oral cavity neuroendocrine carcinoma can be segregated into MCC and small-cell/HGNEC types by morphology and CK20 immunohistochemistry. MCPyV was present by PCR in cutaneous MCC but was not found in mucosal HGNEC.
|Number of pages||9|
|Journal||Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology and Endodontology|
|State||Published - 2010|