Abstract
A 17-year-old girl presented at our department because of left upper abdominal distention. An elastic-hard mass the size of a childʼs head was palpated in the left upper abdomen, but there were no abnormalities on serum chemical tests, including tumor markers. Computed tomography showed a parenchymal tumor located between the stomach and the transverse colon. Magnetic resonance imaging showed low signal intensity on T1-weighted images and high signal intensity on T2-weighted images. Integrated positron-emission tomography and computed tomography revealed high accumulation of tracer in the tumor. A malignant mesenchymoma was suspected, and surgery was performed. The tumor measured 220mm in longest diameter and was located in the posterior portion of the greater omentum. It partially invaded the splenic flexure of the transverse colon and the diaphragm, and the involved regions were concurrently resected. The resected specimen weighed 2,600g. The cut surface of the tumor was grayish white and parenchymal. The histopathological diagnosis was intra-abdominal desmoid tumor. This disease is extremely rare in young women with no history of open surgery. We report this extremely rare case, along with a discussion of the literature.
