抄録
Before surgery, precise diagnosis of submucosal tumors in the gastrointestinal tract remains quite difficult. A 75-year-old female was endoscopically pointed out a gastric submucosal tumor, less than 1 cm in diameter, on the greater curvature of the antrum at a health checks in 1985. Subsequent endoscopic examinations were followed up periodically for 15 years. In 2000, the lesion enlarged to 2 cm. The internal echo pattern on endoscopic ultrasonography (EUS) was almost homogenous but partially hyperechoic. On EUS guided fine needle aspiration biopsy, it was diagnosed as leiomyoma. Because the malignancy could not be excluded, it was resected by laparoscopic approach. Histopathologically, it was mainly composed of uniform myogenic cells, but included abnormal cells in localized area. By immunohistochemical staining for α-smooth muscle actin, malignant cell infiltration to lamina propria was confirmed.
