Appearance of a colovesical fistula at cystoscopy.

Colovesical fistulae typically present with pneumaturia and/or fecaluria. Diverticulitis, inflammatory bowel disease, and malignancies of the colon are the commonest causes. The fistulous tract and adjacent organs are best demonstrated by contrast-enhanced CT scan with rectal contrast or MRI. Biopsy at cystoscopy/colonoscopy is necessary for complete evaluation and treatment planning.