Abstract
A 24-year-old woman with upper right quadrant pain and diarrhea, found to have a palpable mass in the lower abdomen, and a tumor of the right ovary suspected from computed tomography (CT) findings and referred to a gynecology department, was found in blood tests to have high CA125 of 348.9 U/ml. Magnetic resonance imaging (MRI) showed pelvic lesions extending to the supraumbilical region; both ovaries were identified separately. A tumor originating from the mesentery rather than ovarian tumor was suspected and surgery conducted. Both ovaries were found to be normal. A pelvic mass originating from the mesentery had invaded the small intestine. Tumor nodules occurring in the greater omentum were diagnosed by rapid pathological diagnosis as undifferentiated malignancies, necessitating partial small intestine resection together with the tumor originating from the mesentery. The woman's postoperative course was satisfactory and she was discharged on day 15 of hospitalization. Based on pathology, the patient was diagnosed as having a peripheral primitive neuroectodermal tumor (pPNET). Nodes in the greater omentum had a similar histology, so the woman underwent adjuvant chemotherapy. pPNETs of the mesentery are rare, so we report this one together with a review of the literature.
