A CASE OF PRIMARY ADENOSQUAMOUS CARCINOMA OF THE RECTOSIGMOIDAL COLON

Abstract

A case of primary adenosquamous carcinoma of the rectosigmoidal colon is reported and discussed clinicopathologically.A 83-year-old male, who has been visiting a his near practitioner with the chief complaint of diarrhea, admitted to our hospital, because poor appetite and weight-decrease were also gradually developed. Radiological and endoscopic examinations of the lower gastrointestinal tract indicated carcinoma of the rectosigmodial colon. The patient underwent sigmoidoproctostomy. The resected tumor belonged to whole around Borrmann type I with 8.0×10.0 cm in size. Histopathologically it belonged to adenosquamous carcinoma mixdely consisting of well differenciated adenocarcinoma and moderately differenciated squamous cell carcinoma.Adenosquamous carcinoma of the colon occurs so rarely that only 28 cases including this case have been reported in Japan up to now. Our review resulted in that the carcinoma tended to be developed more frequently in youngers, females, and ascending colon, Borrmann type II, and ss or s (+) cases; moreover, that it occurred with squamous cell carcinoma mainly. No theory has been established for mechanism of occurrence, but we support a theory that adenocarcinoma cells are converted to squamous cells.