Squamous cell carcinoma of the stomach: a study of four patients with comments on histogenesis.

The histogenic origin of squamous carcinoma of the stomach (SCS) is controversial. We report the case of a 55-year-old man who developed SCS following successful chemotherapy for generalized well-differentiated lymphocytic lymphoma. The patient's stomach contained both squamous carcinoma arising in squamous metaplasia and chronic atrophic gastritis with intestinal metaplasia. This case is compared to three additional cases of SCS where no such antecedent mucosal changes were evident. The SCS literature is reviewed and the histogenesis regarding the development of pure squamous tumors of the stomach is discussed.