Desmoid-type fibromatosis mimicking uterine fibroid invade the urinary bladder: A case report and literature review

Objective: Desmoid fibromatosis (DF) is a rare, locally aggressive soft tissue tumor. Computed tomography (CT) and magnetic resonance imaging (MRI) play a critical role in the diagnosis of DF and in developing treatment plans. Currently, observation is the primary therapeutic option for a biopsy-confirmed DF. Here, we present a case of a DF that was misdiagnosed as uterine fibroid before surgery. Case report: A 36-year-old woman presented with urinary frequency and a palpable lower abdominal mass, which was suspected as uterine fibroid based on sonography and CT. During surgery, an abdominal wall mass was found to be densely adherent to the bladder. Permanent pathology revealed that the tumor was desmoid-type fibromatosis. Conclusion: Desmoid tumors often occur in the abdomen, abdominal wall, extremities, head, and neck. Abdominal wall DF involving the rectus abdominis muscles is most commonly observed. Conversely, desmoid tumors involving the bladder are less described. The review of similar cases reported since 1985 showed that partial cystectomy was primarily performed for complete resection.