Gastrointestinal: Unusual duodenal follicular lymphoma observed by magnifying endoscopy with narrow‐band imaging

Abstract

Gastrointestinal: Unusual duodenal follicular lymphoma observed by magnifying endoscopy with narrow-band imagingA 77-year-old man was referred to our hospital for a health check-up of the upper gastrointestinal (GI) tract. Conventional esophagogastroduodenoscopy revealed an elevated lesion in the superior duodenal angulus ( Figure 1A). The lesion was irregularly shaped, showed an ill-defined border, and was partially covered with an irregular surface and tiny red spots. After indigo carmine was sprayed on the surface, some nodules were visualized at the border of the elevated lesion ( Figure 1B). Endoscopy with narrowband imaging (NBI) clarified enlarged villi at the surface of the elevated lesion ( Figure 1C). Magnifying endoscopy with NBI revealed irregular microvessels on the surface of each nodule ( Figure 1D). Hence, we thought the elevated lesion could be a nonepithelial tumor such as follicular lymphoma (FL).Biopsy specimens were obtained under NBI magnifying observation for further evaluation. Histological examination of these specimens confirmed the diagnosis of FL, grade 1 (Figure 2). Immunohistochemical staining was positive for CD20, CD10, and bcl-2. The patient was diagnosed with duodenal FL (stage I, according to the Lugano classification). He declined chemoimmunotherapy and chose watchful waiting.GI-FL is rare, accounting for 1%-3.6% of GI non-Hodgkin's lymphoma. The most common site of GI-FL is the duodenum, followed by the ileum and jejunum. Endoscopy shows primarily small whitish polypoid or nodular lesions, which are confluent or scattered. However, the remaining endoscopic findings are uncommon. An elevated lesion with nodules on only a part of the surface, as in our patient, is not typical. Reports and case series of GI-FL observed by magnifying endoscopy with NBI are increasing, and magnifying endoscopy with NBI of duodenal FL has detected coiled and elongated microvascular patterns within the surface of the lesions and opaque white spots under the microvessels.If a unique elevated lesion is found in the duodenum, FL should be considered as a rare differential diagnosis. Observation of the lesion in detail by using magnifying endoscopy with NBI and acquisition of biopsy specimens are important for accurate diagnosis. Contributed by