Treatment of rectal carcinoid tumors.

We investigated the treatment of 24 rectal carcinoid tumors from both the clinicopathologic and prognostic viewpoints. All tumors less than 2 cm in diameter had neither muscle layer invasion nor lymph node metastasis, except for an atypical carcinoid tumor that had both lymphatic permeation and intramural metastasis. One typical carcinoid tumor larger than 2 cm had both several lymphatic permeations and urinary bladder invasion. All cases had a good prognosis with no recurrence and no new metastases. For rectal carcinoid tumors less than 2 cm in diameter, local resection is sufficient, whereas radical operation is required for tumors larger than 2 cm in diameter. For atypical rectal carcinoid tumors, radical operation should be considered even if the diameter is less than 2 cm.