[A Case of Renocolic Fistula Caused by Infected Renal Cyst].

A 76-year-old male was previously found to have a renal cyst at the center of the right kidney, on a computed tomography (CT)scan for examination of another disease. The patient was admitted to the hospital because of fever. The CT scan showed an enlarged mass at the center of the right kidney and an increase in the density of peripheral fat tissue, suggesting an infection of the right renal cyst. In spite of conservative treatment with antibiotics, CT scan on the sixth day of admission revealed an increase in the size of the mass, and penetration in the ascending colon was suspected. An ultrasound-guided abscess puncture was performed, and a pigtail catheter (PC)was placed. Injection of contrast agent through the PC showed communication with the colon. The fistula site was identified using colon fiberscopy, and it was clipped. PC was removed after the closure of the fistula was confirmed by imaging. This is a rare case of renocolic fistula caused by an infected renal cyst, which was diagnosed by colon fiberscopy, and was treated by clipping the fistula.