2017 年 56 巻 12 号 p. 1521-1525
Localized small rectal neuroendocrine tumors (NETs) without any vascular involvement rarely metastasize, and their resection alone is considered curative. We herein report a case of localized rectal NET (10×8 mm) without vascular involvement. Although resected initially, it recurred as liver metastasis 30 years later. For rectal NETs smaller than 10 to 20 mm, surveillance for 12 months is considered sufficient. However, this case suggests that such tumors can recur even 30 years after curative resection. The interval of recurrence is the longest among reported cases.