Leiomyosarcoma of the stomach treated by endoscopic submucosal dissection.

There have been no reports of primary leiomyosarcoma of the stomach treated by endoscopic submucosal dissection (ESD). We report an extremely rare case of gastric leiomyosarcoma that was successfully treated by ESD. An asymptomatic 74-year-old female underwent esophagogastroduodenoscopy for screening in December 2013. A centrally depressed submucosal tumor 10 mm in diameter was detected at the posterior wall of the upper gastric body. Follow-up esophagogastroduodenoscopy conducted 5 months later showed that the tumor diameter had increased to 15 mm. Endoscopic ultrasound revealed a hypoechoic mass located in the second to the middle of the third layer. Endoscopic ultrasound-guided fine-needle aspiration demonstrated a myogenic tumor. The tumor was completely resected by ESD without complications. Immunohistopathological diagnosis of the resected specimen was gastric leiomyosarcoma derived from the muscularis mucosae, with negative lateral and vertical margins. No local recurrence or metastasis has been detected at 36 months after ESD. This is the first report of gastric leiomyosarcoma treated by ESD in the English language literature.