Primary squamous cell carcinoma and adenoacanthoma of the colon

Squamous cell carcinoma and adenoacanthoma rarely occur in the colon or upper rectum and are seen 0.05% as frequently as adenocarcinoma. At the Mavo Clinic, 20 patients with these lesions were seen during a 60-year period. The most plausible explanation for the occurrence of these lesions is that glandular epithelioma is destroyed by deleterious influences and replaced by proliferation of basal cells which, with repeated destruction, undergo anaplasia and loss of ability to redifferentiate normally. The surgical treatment of these tumors is the same as that for adenocarcinoma. The 5-year survival rate for patients with adenoacanthoma and squamous cell epithelioma is 30%, compared to 50% for patients with glandular cancers.