Primary duodenal follicular lymphoma: a case report

Background Follicular lymphoma (FL) is a predominantly nodal disease and extranodal involvement can be seen in widespread nodal disease. Primary extra-nodal FLs are, however, reported in skin, ocular adenexa, Waldeyer's ring and intestine where the majority are mucosa-associated-lymphoid-tissue (MALT) lymphoma and diffuse large B-cell lymphoma. Primary duodenal follicular lymphoma (FL-D) is a distinct mucosal/submucosal variant of FL. Case presentation A 44-year-old man presented with vomiting and subsequent endoscopic examination revealed small bubbly appearances in the first part of the duodenum. Three superficial duodenal mucosal biopsies showed preservation of the normal villous architecture; however, there was a prominent lymphoid infiltrate with prominent follicle formation within the lamina propria of the villi. Whilst CD3/CD5 positive T lymphocytes were present, the majority of the lymphoid cells, and the lymphoid cells forming the lymphoid follicles were positive for CD20, bcl2, bcl6 and CD10 and negative for cyclinD1; CD21 highlighted the follicular dendritic networks. Only very occasional centroblasts were noted within the lymphoid follicles, consistent with Grade-1 FL. Disscussion FL-D, first described in 1997, is a rare disease accounting for 1–3.6% of primary GIT lymphomas. FL-Ds are typically low grade. Transformation to high grade disease or systemic dissemination appears extremely uncommon.