Leiomyosarcoma (GIST, Uncommitted Type) in the Cardiac Region of the Stomach, Report of a Case

This is a case of a 45-year-old man in whom x-ray examination at an annual health check revealed abnomal findings in the stomach. The x-ray examination showed a large tumor shadow with central ulceration in the cardiac region. In the endoscopie examination, the mass was diagnosed as a submucosal tumor and the biopsy from the ulcer revealed the histological findings of leiomyosarcoma. The mass showed exogastric growth in the CT film. The operated specimen with a mass measuring 8.0 X 4.8 X 4.8 cm, had large ulceration at the mucosal surface. The histological diagnosis by H-E staining, was leiomyosarcoma because of the findings of atypical spindle cells with a high density of cellurarity and a large number of mitosis (18/10 HPF). Immunohistochemical staining revealed S100, desmin, and smooth muscle actin were stained negative and bimentin and CD34 were stained positive. This tumor was classified in the group of gastrointestinal stromal tumors (GIST) of uncommitted type. New concepts are required conceiving the prognosis and clinical treatment for this kind of tumor.