case report Mesenteric fibromatosis with intestinal involvement mimicking a gastrointestinal stromal tumour Marek Wronski1, Bogna Ziarkiewicz-Wroblewska2, Maciej Slodkowski1, Wlodzimierz Cebulski1, Barbara Gornicka2, Ireneusz W. Krasnodebski1 1 Department of General, Gastroenterological and Oncological Surgery, Medical University of Warsaw, Warsaw, Poland 2 Department of Pathology, Medical University of Warsaw, Warsaw, Poland Received 30 August 2010 Accepted 20 October 2010 Correspondence to: Dr. Marek Wronski, Katedra i Klinika Chirurgii Ogolnej, Gastroenterologicznej i Onkologicznej WUM, ul. Banacha 1A, 02-097 Warsaw, Poland. Phone: +48-22-599 2482, Fax: +48-22-599 2057; E mail: mwronski@vp.pl Disclosure: No potential conflicts of interest were disclosed. Introduction. Mesenteric fibromatosis or intra-abdominal desmoid tumour is a rare proliferative disease affecting the mesentery. It is a locally aggressive tumour that lacks metastatic potential, but the local recurrence is common. Mesenteric fibromatosis with the intestinal involvement can be easily confused with other primary gastrointestinal tumours, especially with that of the mesenchymal origin. Case report. We report a case of a 44-year-old female who presented with an abdominal mass that radiologically and pathologically mimicked a gastrointestinal stromal tumour. Conclusions. The diagnosis of mesenteric fibromatosis should always be considered in the case of mesenchymal tumours apparently originating from the bowel wall that diffusely infiltrate the mesentery. Key words: mesenteric fibromatosis; desmoid tumour; gastrointestinal stromal tumour; GIST; differential diagnosis; Introduction Mesenteric fibromatosis (MF) or intra-abdominal desmoid tumour is a rare proliferative disease af- fecting the mesentery. MF is a locally aggressive tumour that lacks metastatic potential, but the local recurrence is common. It resembles gastrointesti- nal stromal tumours (GIST) that are mesenchymal neoplasms of the digestive tract and show a var- ied malignant potential. Although GISTs and me- senteric fibromatosis are distinct entities, they are often confused clinically, radiologically and not uncommonly pathologically as well. Misdiagnosis might result in inappropriate therapeutic decisions and worse prognosis. We report a case of a 44-year-old female who presented with an abdominal mass that initially suggested a gastrointestinal stromal tumour. Case report A 44-year-old female was admitted to our depart- ment because of the epigastric pain for the preced- ing two weeks. Her medical history was significant for arterial hypertension, Hashimoto thyroiditis and hypercholesterolemia. Her surgical history re- vealed a cesarean section. There were no desmoid tumours in her family. The physical examination revealed a mass on palpation in the mid-abdomen that was easily movable. The physical examination was otherwise normal. Laboratory findings were unremark- able. The level of CEA was within normal limits. A transabdominal ultrasound (US) showed an ovoid well-delineated homogenously hypoechoic mass that was 10.1 x 6.0 x 7.2 cm in size. There was a hyperechoic area in the central part of the tumour with posterior acoustic shadowing that corresponded to intraluminal air. The tumour was circumferentially attached to the wall of the small bowel (Figure 1). An abdominal computed tomog- Radiol Oncol 2011; 45(1): 59-63. doi:10.2478/v10019-010-0051-7 59