Primary Follicular Lymphoma of the Duodenum Is a Distinct Mucosal/Submucosal Variant of Follicular Lymphoma: A Retrospective Study of 63 Cases

Abstract

Purpose Small series with limited follow-up have suggested primary follicular lymphoma of the duodenum (FL-D) to be an indolent disease. We report our experience on a large series of patients followed for a median time period of longer than 6 years. Patients and Methods The study comprised 63 patients with primary FL-D defined as stage I disease. Endoscopy and detailed pathologic work-up was performed at diagnosis and at restaging to monitor the behavior of the neoplastic process. Results Histologically, all 63 patients had FL, low grade (1 to 2). Duodenal endosonography demonstrated lesions confined to mucosa/submucosa in 19 of 20 patients. At an overall median follow-up of 77 months (range, 12 to 177 months), only two untreated patients had developed nodal disease, the remaining 61 patients never experienced extrasmall intestinal disease and large cell transformation did not occur at all. Among 24 patients followed by watch and wait strategy, seven showed spontaneous complete regression and 17 had stable disease; radiotherapy resulted in complete regression in all 19 patients; anti-CD20 antibody monotherapy achieved complete regression in four patients and stable disease in one patient. Various chemotherapy protocols in eight patients caused complete regression in all of them, but local relapses occurred in three. No patients required surgery or died of disease. Conclusion These findings characterize primary FL-D as a remarkably indolent FL variant, which, even left untreated, does not develop tumorous growth, very rarely disseminates (two of 63 patients) and does not transform to high grade disease. A watch and wait approach appears to be the most sensible strategy.