Adenosquamous Carcinoma of the Stomach: Report of three cases with immunohistochemical study

Ha, Chang Won; Myong, Na Hye; Cho, Kyung Ja; Jang, Ja June

Abstract

Adenosquamous carcinoma originating in the stomach is relatively rare, and the occurrence of such tumor is interesting with respect to its histogenesis. We describe three cases of gastric adenosquamous carcinoma in a 39-year-old man, a 58-year-old woman and a 52-year-old man. They were grossly classified as Borrmann type III or II, revealing no difference from usual advanced gastric adenocarcinomas. Microscopically three cases showed well or moderately differentiated squamous cell carcinoma component occupying large areas of the tumors. Areas of transition from glandular to squamous epithelium were frequently observed. Metastatic foci in the regional lymph nodes also were consisted of two elements. On immunohistochemical study, CEA immunoreactivity was found not only in adenocarcinoma component but also in squamous cell components, in comparison to cytokeratin which was detected only in squamous areas. The immunohistochemical findings of CEA reactivity in both components, and the presence of microscopic transitional zones support the hypothesis of squamous metaplasia occurring in an already existing adenocarcinoma in the development of adenosquamous carcinoma of the stomach.