Basosquamous (transitional cloacogenic) carcinoma of the sigmoid colon.

A case of basosquamous or so-called transitional cloacogenic carcinoma of the sigmoid colon, which arose above the pelvic brim at the peritoneal reflection, is reported. We were not able to find a report of this histologic type of tumor arising this far from the pectinate line of the anus, which is the most common primary site of this neoplasm. Possibilities as to the histogenesis of this tumor at this site are stated. The neoplasm also produced parathyroid hormone (PTH) and also possibly adrenal corticotrophic hormone (ACTH), which had not been previously reported for this specific neoplasm.