Squamous-cell Carcinoma of the Colon: Report of a Case and Review of the Literature

We encountered an extremely rare case of squamous cell carcinoma of the colon. The patient, a woman aged 72, was examined because of chief complaints of a mass in the upper abdomen and constipation in June 2003. Colonoscopy disclosed a tumor around the hepatic flexure eventuating in marked stricture formation, and a diagnosis of moderately differentiated squamous cell carcinoma was made on biopsy. Although extensive tumor cell dissemination to the peritoneum was noted upon laparotomy, a right hemicolectomy was performed as extensively as possible. Histologically, the tumor was a moderately differentiated squamous cell carcinoma without adenocarcinomatous components, being classified as Type 3, ss, nl (+), P3, H1, M (-), and stage IV. There was no evidence of other primary lesions ; hence the case was diagnosed as primary squamous cell carcinoma of the colon. Despite low-dose FP therapy given to the patient postoperatively, the disseminated tumor continued to grow, and the therapy regimen was switched to CPT-11 plus 5' -DFUR. Serum levels of tumor markers temporarily decreased, but a further increase in the tumor size ensued. The patient died of the malignancy 5 months postoperatively. Squamous cell carcinoma of the colon is an extremely rare malignancy, and a search of the literature has revealed eighteen cases reported in Japan including the present case. In most cases the disease had already advanced at the time of diagnosis and was associated with an unfavorable prognosis. Further accumulation of cases is needed to establish therapeutic approaches in advanced cases and to clarify the underlying pathogenetic mechanism.