Fistulization of a ruptured mesenteric desmoid tumor to the small bowel in a patient with familial adenomatous polyposis: a case report

Abstract

We report an extremely rare case of familial adenomatous polyposis whose mesenteric desmoid tumor that fistulated to the small bowel and ruptured. Optimal surgical treatment was selected for this patient according to imaging evaluation preoperatively. A 41-year-old man underwent restorative proctocolectomy and pancreatoduodenectomy for treatment of familial adenomatous polyposis with a sigmoid colon and duodenal cancer 5 years previously. At 3 years after surgery, he developed mesenteric desmoids and underwent chemotherapy as conservative treatment. Under the treatment, he developed abdominal pain and was admitted to our hospital. An increased white blood cell count, increased C-reactive protein level, and peritonitis were found upon presentation. Abdominal computed tomography （CT） revealed fluid collection with free air in the abdomen. After CT-guided drainage, we performed additional imaging evaluations and diagnosed the patient with a mesenteric desmoid tumor involving the superior mesenteric artery; the tumor had fistulated to the small bowel and ruptured intraperitoneally. We resected the fistulated small bowel from the desmoid and opened the fistula in the desmoid. However, we did not resect the desmoid to avoid the risk of short bowel syndrome. An ileostomy was created and mucous fistula construction was performed. The patient recovered well and underwent a follow-up CT scan to check the remnant desmoid at our outpatient clinic.