NKX2-1 and neoplasm: Subsequent skin mapping punch biopsy showed a poorly differentiatedcarcinoma of uncertain origin infiltrating skeletal muscle, dermis, and subcutis.Subsequently, immunostains of both fine needle aspiration and punch biopsy samplesshowed tumor cells positive for CK7, AE1/AE3, and focally positive for CK5/6 andnegative for CK20, thyroid transcription factor-1, thyroglobulin, CEA, chromogranin,synaptophysin, CD56, CDX2, RCC, napsin-A, S-100, and p16.