Clinical features and outcomes of duodenal-type follicular lymphoma: A single-center retrospective study.

Duodenal-type follicular lymphoma (FL) is a rare and newly recognized disease. Few data are available on the outcomes and treatment strategies for patients with duodenal-type FL. We aimed to investigate the clinical features and outcomes of duodenal-type FL. We defined duodenal-type FL as involvement of the duodenum, without nodal or extranodal lesions other than intestinal lesions, pathologically diagnosed as FL. We reviewed 26 patients with duodenal-type FL between January 2011 and December 2020 at Kobe City Hospital Organization, Kobe City Medical Center General Hospital. In particular, patients were selected for the watch and wait (WW) strategy and followed up with regular esophagogastroduodenoscopy about once a year at our institution. The patient characteristics were as follows: median age 63.5 years (range: 42-78), sex (male, 15; female, 11), stage (I, 26), and grade (I, 26). Regarding treatment strategies, 23 patients were selected for the WW strategy, and three patients received initial rituximab therapy. The median follow-up period was 65.5 months (range: 0.2-109). Five-year progression-free survival and 5-year overall survival rates were 86.3% and 100%, respectively. Among the 23 patients selected for the WW strategy, six had spontaneous complete regression, and 14 had stable disease, and three had progressive disease, including one with histologic transformation. The WW strategy for patients with duodenal-type FL could be an appropriate and safe treatment option. However, in several cases, disease progression was documented, and regular follow-up is important.