A giant mesenteric fibromatosis involving the muscular layer of the colon wall: A case report

RATIONALE: Mesenteric fibromatosis (MF) is a rare tumor whose biological behavior is intermediate between benign fibrous neoplasms and fibrosarcomas, and the characteristic of these tumors are local aggressive lesions which is prone to local recurrence but non-metastasizing. The common symptom is abdominal distention or painless mass. We report a case of giant MF in abdominal cavity with abdominal distention as the main symptom. PATIENT CONCERNS: A 26-year-old male presented with 2-month history of abdominal distention, lack of appetite, and symptoms grew progressively more debilitating with time. DIAGNOSES: This patient underwent a contrast-enhanced computed tomography scan which showed a giant (37 × 25 × 13 cm), inhomogeneous enhancing, well-defined, and soft tissue density mass in abdominal cavity, possibly arising in mesocolon, which suggested a high possibility of MF. The postoperative pathology showed that the tumor cells to be positive for β-catenin, vimentin, negative for CD34, CD117, DOG-1, S-100, Desmin, which confirmed the diagnosis of MF. INTERVENTIONS: Exploratory laparotomy was performed, which revealed a large mass involving the transverse colon wall, the root of mesocolon, and encasing the middle colic vessels and the 1st branch of jejunal arteries. The complete surgical resection was performed and the mass weighted 10 kilograms (kg). OUTCOMES: The patient recovered uneventfully and was discharged 9 days after surgery. Three-month, 6-month, 12-month and 18-month on follow-up after surgery, showed no evidence of recurrence. LESSONS: The MF is a very rare tumor, especially a giant tumor (10 kg) involving the muscular layer of colon wall. In addition, treatment of giant MF still remains a challenge. We consider that surgical resection with negative margins is the goal but not at the expense of damaging the function of vital organs. Specific measures should be considered based on the individual patient in order to relieve symptoms and improve quality of life.