Intraluminal rectal cancer metastasis to the small bowel: An extremely rare case report.

Prolonged survival in patients suffering from colorectal cancer (CRC) may lead to the emergence of rare metastatic sites that are not well-documented in the literature. We herein describe a very rare case of an intraluminal small intestinal metastasis in a patient with previously resected CRC. A 71-year-old Caucasian male patient with a history of rectosigmoid junction cancer was initially treated with anterior resection. The tumor was classified as pT3pN0 (0/26) M0, stage II. Eighteen months after the primary surgery, local recurrence was detected in the presacral region, and the patient received combined image-guided radiotherapy and chemotherapy. Two months later, due to residual disease at the level of the anastomosis, the patient underwent additional low anterior resection with a diverting stoma. During extensive adhesiolysis, a small palpable intraluminal mass was identified in the jejunum, and segmental small bowel resection was performed. Pathological examination of the resected specimen confirmed that the lesion was a metastasis from the CRC primary. The precise mechanism and clinical significance of CRC metastasis to the small bowel remain unclear. There is limited clinical experience with this condition, as <20 cases have been reported in the literature to date. The main symptoms leading to evaluation, diagnosis and surgical resection are bowel obstruction and bleeding. The present case highlights the possibility of uncomplicated presence of metastatic CRC in the small bowel. Therefore, dilligent inspection of the peritoneal cavity, including the entire length of the gastrointestinal canal, is of paramount importance, particularly in cases of recurrent CRC.