A rare case of duodenal-type follicular lymphoma in rectum appearing as hyperplastic polyp with metachronous appearance in duodenum and stomach

Hyperplastic polyps consist a very frequent finding in colonoscopy having a very low potential to malignancy. According to the international guidelines, it is recommended that all polyps should be resected except for diminutive (≤ 5 mm) rectal and rectosigmoid polyps which are predicted with confidence to be hyperplastic. Therefore, in departments where optical diagnosis can be ensured, a "resect and discard" strategy may be implemented for diminutive polyps. In our case, a duodenal-type follicular lymphoma was detected in a 5 mm rectum polyp with hyperplastic appearance. After 4 months, the lymphoma was detected also in stomach and duodenum. Under therapy with Rituximab, she is in remission. To our knowledge, there has never been reported such a case in the literature. Furthermore, it alerts us that we should be very cautious with the optical diagnosis and the "resect and discard strategy".