Squamous-cell carcinoma of the colon responsive to combination chemotherapy - Report of two cases and review of the literature

PURPOSE: The majority of colorectal neoplasms diagnosed are adenocarcinomas . Other histologies such as squamous, adenosquamous, carcinoid tumors, or l ymphoid tumors are occasionally identified. Given the rarity of squamous-ce ll tumors, it is very difficult to study their natural course and response to therapy. An attempt is made to describe the frequency, anatomic location , and response to therapy with a review of the literature. METHODS: From th e Cancer Registry at the University of Missouri-Columbia Ellis Fischel Canc er Center, tumors of the colon identified above the dentate line were selec ted for chart review. Data were extracted from cases between the years 1940 and 1996. The key terms used to identify cases were epidermoid, squamous c ell, and cancer of the rectum or colon. Using this approach, forty patients were identified and each record was reviewed. RESULTS: The majority of the se cases were anal cancers with proximal extension into the rectum and were excluded. Of 4,561 cases of epithelial colon and rectal cancers identified , only one additional case of squamous-cell cancer could be verified. In th is report we describe a patient with a primary squamous-cell carcinoma of t he sigmoid colon with metastatic disease to the Liver at diagnosis who resp onded to systemic chemotherapy. We believe this to be the first reported ca se of this rare tumor type in which the patient's tumor responded to system ic chemotherapy. Two cases with a thorough review of literature are present ed. CONCLUSIONS: Primary squamous-cell carcinoma of the colon is a rare mal ignancy of unknown cause and pathogenesis. Metastatic tumors to the colon s hould be ruled out in all cases before therapy. Early detection and surgery remain the main therapeutic options, but as presented in our case, respons e to chemotherapy in advanced disease is encouraging.