Basosquamous (transitional cloacogenic) carcinoma of the sigmoid colon

Abstract

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.

Basaloid carcinoma of the colon arising at the splenic flexure

“…Central necrosis was seen in many of the tumour islands. This constellation of findings is common in basaloid cloacogenic carcinoma of the anal canal 1–3 and has been described in the other cases of this tumour reported outside the anal canal 4–6 …”

“…Basaloid carcinomas are rare outside the anal canal and only three well‐documented cases of these tumours have been reported; all three occurred in the sigmoid colon 4–6 . Outside the anal canal, it has been postulated that these tumours arise from cloacogenic embryologic rests, squamous metaplastic epithelium, or totipotential basal cells 4–6 . In this report of a basaloid carcinoma at the splenic flexure, we document the fourth, and most proximally located case, of such a neoplasm outside the anal canal.…”

“…Histological and ultrastructural studies have indicated that these neoplasms may also arise from transitional cloacogenic epithelium lining anal ducts or from the basal layer of anal squamous epithelium 2,3 . Basaloid carcinomas are rare outside the anal canal and only three well‐documented cases of these tumours have been reported; all three occurred in the sigmoid colon 4–6 . Outside the anal canal, it has been postulated that these tumours arise from cloacogenic embryologic rests, squamous metaplastic epithelium, or totipotential basal cells 4–6 .…”

Basaloid (Cloacogenic) Carcinoma Mimicking Intraabdominal Abscess: Report of a Case and Review of the Literature

“…These are reported between 1977 and 2002. Strate et al presented the first case of CC originating from the sigmoid colon and located outside the anal canal [4]. Hall-Craggs and Toker reported a second case originating from the sigmoid colon [5].…”

“…Histological and ultrastructural studies have indicated that these neoplasms may also arise from transitional cloacogenic epithelium lining the anal ducts or from the basal layer of anal squamous epithelium [1,2,3]. Outside the anal canal, it has been postulated that these tumors arise from cloacogenic embryologic remnants, squamous metaplastic epithelium, or totipotential basal cells [4,5,6]. …”