Adenosquamous carcinoma of the stomach. Histogenetic and ultrastructural studies.

Adenosquamous carcinoma of the stomach in a 45-yr-old Japanese woman was studied ultrastructurally and light microscopically. The tumor consisted of combined areas of poorly and moderately differentiated adenocarcinoma and squamous cell carcinoma, with keratinization. Noteworthy was the demonstration of individual cells containing both tonofibrils and mucous vacuoles. The frequencies of this type of tumor in early and advanced gastric carcinomas are given attention and the pathogenesis is discussed with respect to our own observations and to data in the literature.