[A Case of Sigmoid Colon Cancer with Retroperitoneal Fibrosis Using Intraoperative Indocyanine Green Fluorescence Angiography for Colorectal Anastomosis].

A 72-year-old man was presented with anemia and diagnosed with sigmoid colon cancer by colonoscopy. CT showed a soft tissue density around the retroperitoneum, leading to the diagnosis of retroperitoneal fibrosis. Stenosis of left ureter, inferior mesenteric artery, and left colic artery due to the soft tissues were detected. Sigmoidectomy and retroperitoneal biopsy were performed, and colorectal anastomosis was completed after confirming the intestinal blood flow by ICG fluorescence angiography. In retroperitoneal fibrosis, identifying blood vessels intraoperatively can be difficult. ICG fluorescence angiography is useful for reliable anastomosis in colorectal cancer surgery with retroperitoneal fibrosis.