[Resection of a Desmoid Tumor Originated from Greater Omentum with No History of Open Surgery].

Here we report a case of a 41-year-old male patient who underwent resection of a desmoid tumor originating from the greater omentum with no history of open surgery. An elastic hard mass 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 near the descending colon. Integrated positron-emission tomography and computed tomography revealed moderate accumulation of tracer in the tumor. An intra-abdominal malignant mesenchymoma was suspected and surgery was performed. The tumor was located in the anterior portion of the greater omentum. It partially invaded the diaphragm, and the affected regions were concurrently resected. The resected specimen measured 80 mm at longest diameter. The cut surface was grayish white and parenchymal. The histopathological findings showed the atypical spindle shaped tumor cells grown with collagen fiber progression. Immunohistochemical staining for β-catenin showed strong staining in the nuclei and cytoplasm of tumor cells. The patient was diagnosed with desmoid tumor originating from the greater omentum. The desmoid tumor with no history of open surgery was rare. We report this rare case, along with a discussion of the literature.