neat carcinoid tumors-small size belies deadly intent: high rate of nodal metastasis in tumors ≤1 cm in size

Neuroendocrine tumors (NETs) account for 2% of tumors of the gastrointestinal tract, most occurring in the small intestine. A size of 2 cm is generally regarded as a cut-off point for risk of lymph node metastasis in intestinal neuroendocrine tumors in the absence of other high-risk features; however, metastatic disease has been reported in 12% of tumors of the jejunum and ileum measuring <= 1 cm or less. Archives from 2 institutions were searched for ileal NETs measuring <= 1 cm or less, and selected data were recorded. Twenty-one ileal NETs were identified measuring <= 1 cm. Six (29%) were multifocal and 7 (33%) had distant metastasis at diagnosis. Regional lymph nodes were examined in 14 cases (67%), and 10 of these cases (71%) showed lymph node metastasis. Mean primary tumor size in cases with nodal metastasis was 7.3 mm. In this series of ileal NETs <= 1 cm in size, the rate of lymph node metastasis was 48% overall and 71% for cases with regional lymph node resections. In addition, 33% showed distant metastasis at the time of diagnosis. Tumors as small as 3 mm and those confined to the submucosa can give rise to nodal metastasis, emphasizing the need for consideration of local resection with regional lymphadenectomy, even for subcentimeter ileal NETs. (C) 2016 Elsevier Inc. All rights reserved.