[A Case of Primary Sigmoid Colon Lymphoma Presenting with Sigmoidovesical Fistula in a Patient with a Long History of Ulcerative Colitis].

A 73-year-old male patient with a 16-year history of ulcerative colitis presented to our hospital with a history of pneumaturia and fever. Cystoscopy and a computed tomography scan showed sigmoidovesical fistula. Colonoscopy showed a necrotic tumor along with sigmoidovesical fistula. A biopsy was not sufficient to make a definitive diagnosis of the tumor. Total colectomy with ileostomy and partial cystectomy were performed. A pathological examination showed diffuse large B-cell lymphoma of the sigmoid colon. On postoperative day 35, delayed dehiscence of the bladder wall was detected and a biopsy of the bladder wall showed lymphoma. Standard systemic chemotherapy (R-THP-COP) was administered and the defect of the bladder was closed. Three years and 2 months postoperatively, the patient has no local recurrence or distant metastasis.