KRT20-/SATB2+/MCPyV+ Sinonasal Merkel Cell Carcinoma: A Detailed Immunohistochemical and In Situ Hybridization Study. (PubMed, Int J Surg Pathol)
Relevantly, KRT20, KRT5/6, chromogranin A, p40, p63, HMB45, NF, TTF1, TDT (DNTT), PAX5, p16, KIT, as well as high-risk HPV and EBER1/2 (both by ISH), were negative. This report illustrates that a detailed immunohistochemical study, including STAB2 and MCPyV markers, as well as a careful clinical workup, are essential to adequately classify high-grade neuroendocrine carcinomas, especially KRT20-negative MCC.