The purpose of this article is to discuss the application of TEM in the treatment of rare rectal tumors.

From April 2006 to May 2018, 157 patients with rare rectal tumors were treated in Peking Union Medical College Hospital. To collect clinical data and establish a retrospective and accurate database. There were 89 males and 68 females. The average diameter of the tumors was (1.2±0.7) cm, (0.2~5.3 cm) and the average distance from the anal margin was (6.6±2.3) cm, (2~12 cm). The demographic characteristics, surgical details, tumor characteristics, complications and follow-up data were analyzed.

All patients were completely resected with negative incision margin. There were 3 intraoperative complications and 21 post-operative complications. Histopathological findings were reported in 114 cases of neuroendocrine tumors (NETs), thirty-five cases of gastrointestinal stromal tumors (GISTs), two cases of melanoma, two cases of lymphoma and 2 cases of leiomyoma, one case of lipoma and 1 case of squamous cell carcinoma. 145 patients were followed up for (56.25±32.13) months (19~144 months). Two patients died, one had local recurrence and one had lymph node metastasis. One case developed rectovaginal fistula one month after operation. No local recurrence, metastasis or fecal incontinence occurred in the other patients. In the analysis of neuroendocrine tumor subgroup, there was no significant difference in operation time, intraoperative bleeding and postoperative hospital stay between first operation group and the second surgery failed group. In gastrointestinal stromal tumor subgroup, there was also no significant difference between the neoadjuvant therapy group and without neoadjuvant therapy group in operation time, intraoperative bleeding and postoperative hospital stay.

TEM is a reliable `treatmentfor rare rectal tumors. The incidence of complications is low and the curative effect is satisfactory.

Anal canal; Rectal neoplasms; Transanal endoscopic microsurgery (TEM); Rare rectal tumors; Neuroendocrine tumors; Gastrointestinal stromal tumors; Full-thickness resection