Primary follicular lymphoma of the duodenum as an incidental finding on upper gastrointestinal endoscopy.

Primary follicular lymphoma of the duodenum (FLD) is a rare variant of follicular lymphoma (FL), which represents only 1-4% of gastrointestinal non-hodgkin lymphomas (NHL). It usually appears in the second portion of the duodenum as micronodular lesions and the diagnosis is often incidental. Unlike other NHLs, the prognosis is excellent and the treatment ranges from "watch and wait" to rituximab-based immunochemotherapy regimens, depending on the symptoms and the presence of systemic involvement.