Thus, an immunohistochemical panel showing positivity for neuroendocrine markers, NF, CK20 (paranuclear dot-like pattern) and negativity for TTF-1, CK7, melanocytic and lymphocytic/lymphoblastic markers offer high sensitivity and specificity rates for differentiating MCC from the common histologic mimickers, such as SCLC, neuroblastoma, Ewing sarcoma, melanoma, lymphomas, and germ cell tumors (Table 2) [92,93,94,95,96,97,98]. The gene discussed is TTF1; the disease is melanoma.