Pedunculated rectal carcinoid removed by endoscopic mucosal resection: a case report

Carcinoid tumors generally appear as yellow/gray or tan submucosal nodules. We experienced a case of pedunculated rectal carcinoid showing a mushroom-like appearance. The case was a forty years old woman who was admitted to our hospital due to rectal bleeding. Colonoscopy revealed a pedunculated polyp presenting a mushroom-shaped appearance measuring 13 mm in diameter in the rectum. The histological diagnosis of specimens obtained by biopsy was adenocarcinoma and transanal ultrasonography revealed the tumor localization within the submucosal layer in the rectum. Endoscopic mucosal resection (EMR) was performed. Histopathological examination established the diagnosis of carcinoid tumor in the rectum. Frequencies of the pedunculated type in rectal carcinoids were reported to be 2.4% to 7.1% in the literature. Because of its rarity, pedunculated configuration may confuse the endoscopic diagnosis of carcinoids. Treatment for carcinoids of 1 to 1.5 cm in size remains controversial. Although such tumors are technically respectable by EMR, careful attention must be paid in dealing with these tumors because there may be unexpected behaviors of the tumors.

Minimally invasive surgery for carcinoid tumors in the rectum

Most carcinoid tumors of the rectum are confined to the submucosa with a size less than 1-2 cm and are usually suitable for local excision, as metastasis to the regional nodes is limited. Endoscopic excision of carcinoid tumors has been performed for this entity as a least invasive method but incomplete resection and/or unclear surgical margin and curability have been reported to occur in 24-42% of cases because of a limited resection up to the submucosal layer and burn effect. Transanal local excision has often been applied for rectal carcinoid tumor as a least invasive method among local excision procedures to accomplish full thickness excision for determining the curability. However, it is often difficult to obtain free access with a sufficient surgical field by the conventional method. Transanal endoscopic microsurgery (TEM) has appeared as a useful option to access a high tumor with fine visibility but special caution has to be taken for tumors sited above the peritoneal reflection. To facilitate full thickness excision even for high tumors, novel local excisional technique called minimally invasive transanal surgery (MITAS) has been developed and used for local removal of carcinoid tumors in the rectum. A specially designed anal retractor connected to the Octopus retractor holder with several novel techniques facilitated excisional procedures around the anus with a sufficient fixed surgical field and an ENDO-stapler allowed the simultaneous excision and anastomosis to be performed. The technique facilitated total excisional biopsy with less operative time and blood loss, and no mobility or mortality in 12 patients with rectal carcinoid tumors.

Clinical efficacy of video-assisted gasless transanal endoscopic microsurgery (TEM) for rectal carcinoid tumor

BACKGROUND

We used video-assisted gasless transanal endoscopic microsurgery (TEM) to evaluate 12 consecutive patients for carcinoid tumor with pathologically typical features in the proximal rectum. The study parameters included feasibility, results and final outcome.

METHODS

A scope with an optical angle of 25 and a 7-mm diameter was used for TEM. The carcinoid tumor was resected in full thickness. Primary closure was accomplished using a running suture of 3-0 braided absorbable suture.

RESULTS

The tumor in these patients was <15 mm in diameter. It was localized within the submucosal layer on the oral side from the peritoneal reflection and unreachable via Park's transanal approach. The mean duration of the operation was 63 min. The postoperative course in all patients was free from significant complications, and all patients were discharged within 1 week. None of the patients had postoperative pain or required sedatives.

CONCLUSION

Video-assisted gasless TEM is a simple and minimally invasive procedure to treat benign carcinoid tumors in the proximal rectum.