Pancreatic follicular lymphoma: a report of two cases and literature review

Okamoto, Takeshi; Sasaki, Takashi; Nishimura, Noriko; Takamatsu, Manabu; Mori, Chinatsu; Mie, Takafumi; Furukawa, Takaaki; Yamada, Yuto; Takeda, Tsuyoshi; Kasuga, Akiyoshi; Matsuyama, Masato; Ozaka, Masato; Maruyama, Dai; Sasahira, Naoki

Primary pancreatic lymphomas are extremely rare, accounting for 0.1–0.5% of malignant lymphomas and about 0.2% of primary pancreatic tumors. They occur most commonly in the pancreatic head of elderly males, with diffuse large B-cell lymphoma being the most common subtype. Primary pancreatic follicular lymphoma is the most commonly reported primary pancreatic indolent lymphoma, accounting for 9–14% of primary pancreatic lymphomas. We report two cases of primary pancreatic follicular lymphoma treated with obinutuzumab, a second-generation humanized anti-CD20 monoclonal antibody, and bendamustine. One was diagnosed by endoscopic ultrasound-guided fine-needle aspiration, while the other required laparoscopic lymph node sampling to reach a diagnosis. Both achieved complete response with induction therapy and opted for maintenance therapy with obinutuzumab. We also conducted a literature review of primary pancreatic follicular lymphoma cases reported over the last 30 years.