Abstract
[Introduction] Colovesical fistulas are mostly caused by diverticulitis and sometimes colon or bladder cancer, and so treatment should be carefully selected. [Case] A 77-year-old male visited our hospital because of pollakiuria was diagnosed as to have intractable cystitis. An abdominal CT scan demonstrated a tumor mass which protruded downward from the sigmoid colon and displaced the bladder, and pneumatization in the bladder. With enteroclysis, whole-circumferential stenosis of the sigmoid colon and multiple diverticula and a sigmoidovesical fistula in its oral side were observed. It was difficult to observe the lesion by lower gastrointestinal endoscopy and cystoscopy, and no definitive diagnosis of cancer could be made before surgery. [Treatment and Diagnosis] We performed sigmoidectomy and partial cystectomy. The pathological diagnosis was colovesical fistula due to extramurally growing colon cancer. [Discussion] Internal fistula-forming colon cancer is a locally advanced cancer, but the lymph node metastasis positive rate is comparatively low. It is considered that the malignancy might behave in a different biological manner from cancers involving other organs. We herein report a case of extramurally growing colon cancer forming fistulas within the bladder with some bibliographical considerations.
