The utility of endoscopic ultrasound-guided fine-needle aspiration and robotic surgery for submucosal-type metastatic rectal cancer with persistent descending mesocolon.

Persistent descending mesocolon (PDM) is a congenital failure of fusion of the descending mesocolon, resulting in a lack of retroperitoneal fixation, rightward displacement, adhesions, and vascular displacement that complicate colorectal surgery. Renal cell carcinoma (RCC) metastasis to the rectum is extremely rare. The patient was a 65-year-old man who had a history of RCC with a rectal tumour. Colonoscopy revealed a submucosal tumor-like lesion, and endoscopic ultrasound-guided fine needle aspiration confirmed metastatic RCC. The shape of the colon on the 3D CT suggested PDM. On operation, adhesions had formed between the transverse and sigmoid colon. First, robot-assisted adhesiolysis was performed, thereby enabling conventional rectal resection. The postoperative course was uneventful. We reported a rare case of rectal metastatic tumor. This case also had PDM, and we needed to perform a non-standard procedure. This report will assist in similar cases of disease in the future.