2022 Volume 75 Issue 1 Pages 1-7
According to guidelines for the treatment of neuroendocrine tumors, local resection such as endoscopic treatment is recommended for rectal neuroendocrine tumor （NET） with a diameter of less than 10 mm. We report a case of 5-mm rectal NET in a patient with recurrent multiple liver metastases in the early postoperative period after radical rectal resection.
A 59-year-old woman underwent routine colonoscopy, which revealed a rectal submucosal tumor. Biopsy of the tumor and pathological and immunohistochemical analyses demonstrated NET. Robot-assisted low anterior resection with lymph node dissection was performed. The postoperative histopathological examination revealed NET-G1, 5×5 mm, ly0, v1, and lymph node metastasis at station 251 （Japanese Classification of Colorectal Carcinoma, 9th edition）, Stage IIIB.
Five months after surgery, multiple liver metastases recurred, and partial hepatectomy was performed. Postoperative histopathological examination showed that the liver metastases were NET-G2 and that the NET grade had worsened. The risk of relapse was considered to be high, and additional treatment is currently being administered.
Surgical resection should be considered for patients with risk factors such as central depression, even if the lesion is small, as in this case.
