Abstract
BACKGROUND: Gastric gastrointestinal stromal tumor (GIST), intro-abdominal and retroperitoneal neoplasms are distinct tumors arising from different cell layers; therefore, coexistence of such tumors is relatively rare. CASE PRESENTATION: A man complained of early satiety for 2 mouths, whose upper gastrointestinal (GI) endoscopy showed a tumor arising from the greater curvature of gastric body and extending into the lumen. Abdominal computed tomography (CT) revealed coexistence of gastric, intro-abdominal and retroperitoneal masses. Wedge resection for gastric tumor, resection for intro-abdominal and retroperitoneal tumors were done. The postoperative histological examination suggested simultaneous development of a gastric GIST, intro-abdominal and retroperitoneal myxoid liposarcomas. CONCLUSION: Although both GISTs and liposarcomas originate from mesenchymal tissues, simultaneous development of a gastric GIST, intro-abdominal and retroperitoneal liposarcomas is the first such case to be reported in the literature.