TTF1 and sigmoid neoplasm: Immunophenotyping demonstrated TTF-1 nuclear positivity in the metastatic tumor alongside a classic colorectal profile: cytokeratin 7 (CK7) negativity, cytokeratin 20 (CK20) positivity, strong caudal-type homeobox transcription factor 2 (CDX2) and special AT-rich sequence-binding protein 2 (SATB2) nuclear expression, and absence of Napsin A. The patient underwent surgical resection of the primary sigmoid colon tumor and received 16 cycles of capecitabine plus bevacizumab chemotherapy.