A rectal carcinoid tumor of less than 1 cm in diameter with lymph node metastasis: a case report and a review of the literature.

We report herein, a patient with a rectal carcinoid tumor of less than 1 cm in diameter with lymph node metastasis, and discuss a surgical policy for these lesions with reference to other such cases reported in the literature. A 40 year old female was admitted with a rectal mass and colonoscopy revealed a subpedunculated lesion, 1 cm in diameter, with a depression in its tip. A diagnosis of carcinoid was made by biopsy and transsacral excision performed. The excised specimen revealed a subpedunculated lesion measuring 7 X 6 X 6 mm with a central depression. The tumor was histologically confined to the submucosa but lymphatic invasion with pararectal lymph node involvement was observed. A radical proctectomy was thus performed. The incidence of metastasis from rectal carcinoids with a diameter of 1 cm or less is very low ranging from 1.5 to 3.4 per cent, and it therefore seems that most lesions of 1 cm or less in diameter can be treated by local excision alone. Thus, although it is recommended that local excision be performed first to determine the extent of spread, lymphatic vessel invasion and lymph node metastasis, radical surgery is indicated if lymphatic invasion or nodal involvement is present, even when muscle invasion is absent.