Abstract
Fish bone ingestion is common in Japan, but gastrointestinal perforation is rare. We report a 67-year-old man with a fish bone perforating the descending colon and penetrating a renal cyst, causing severe retroperitoneal infection. CT revealed a linear hyperdense structure extending into the cyst with intralesional gas. Conservative therapy failed, and robot-assisted laparoscopic surgery was performed, including fish bone removal, colonic serosal repair, and nephrectomy. Recovery was uneventful, and the patient remained recurrence-free at 6 months. This is the first report of robot-assisted laparoscopic management of fish bone-induced colonic perforation with renal involvement.