CARCINOID OF LESS THAN 2CM IN DIAMETER WITHOUT MUSCULARIS INVASION ASSOCIATING WITH LYMPH NODE METASTASIS -REPORT OF TWO CASES

It is designated that carcinoids of the rectum with the diameter of more than 1cm and less than 2cm without invasion into muscularis are candidates for local resection. We have, however, experienced 2 such cases in which lymph node metastasis was detected after radical operation. In Case 1, a 51-year-old woman had a Isp type carcinoid of Rb and 17mm in diameter with a central depression (histologicaly, sm, ly1, and v1), as well as a rectovaginal tumor (which eventually lymph node metastasis). Both tumors were locally excised. Thereafter, abdominoperineal excision of the rectum and associated resection of the uterus and vaginal posterior wall were added, when another metastasis to internal iliac lymph node was found. There have been no signs of recurrence, 8 years after the operation. In Case 2, a 37-year-old man had a Isp type carcinoid of Rs and 13mm in diameter, and underwent a low anterior resection of the rectum. Histologically, the resected material showed sm, ly1 and v0, and a metastasis in the pararectal lymph node of group I was detected. There have been no signs of recurrence, 2 years after the operation. From our experience with these cases, we may have a useful indication for the treatment of rectal carcinoids with the diameter of more than 1cm and less than 2cm without muscularis invasion: It seems likely that both a thorough preoperative exploration with EUS for pararectal lymph node metastasis and a consideration of resected material for vascular invasion are very important to select more appropriate treatment predicting possible lymph node metastasis.