Primary Duodenal Follicular Lymphoma Treated With Rituximab Monotherapy and Followed-up for 15 Years Anna Seki a,b＊ , Masaya Iwamuro c , Masao Yoshioka a , Nobuharu Fujii d , Hiroyuki Okada e , Soichiro Nose f , Katsuyoshi Takata g , Tadashi Yoshino g , and Kazuhide Yamamoto b Departments of a Internal Medicine and f Anatomic Pathology, Okayama Saiseikai General Hospital, 700-8511 Japan, Departments of b Gastroenterology and Hepatology, and c Molecular Hepatology, g Pathology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Departments of d Hematology and Oncology, and e Endoscopy, Okayama University Hospital, Okayama 700-8558, Japan A 41-year- old woman was diagnosed with duodenal follicular lymphoma. She had no other lesions and was assigned to a “watch and wait” policy. Swelling of the inguinal lymph nodes appeared 45 months later, and rituximab monotherapy resulted in complete remission. However, follicular lymphoma recurred in the stomach, rectum and mesenteric and external iliac lymph nodes 81 months after the therapy. The patient received rituximab monotherapy again and has remained in complete remission in the fifteenth year after the initial diagnosis. This case suggests the usefulness of rituximab mono- therapy in the long- term management of intestinal follicular lymphoma. Key words: follicular lymphoma, duodenum, rituximab ollicular lymphoma is defined as a neoplasm of transformed follicle center B cells [1]. Although most follicular lymphoma cases present with nodal involvements, primary follicular lymphoma lesions can arise in the gastrointestinal tract [2-7]. The number of patients newly diagnosed with primary gastrointestinal follicular lymphoma has been increas- ing in recent years, as increasing numbers of endosco- pists and gastroenterologists become familiar with this entity. As a result, primary gastrointestinal follicular lymphoma was listed in the latest version of the World Health Organization (WHO) classification of lymphoid tissues as a distinct variant of systemic follicular lymphoma [6]. However, the standard therapy for primary gastrointestinal follicular lymphoma remains to be determined. Moreover, only a few reports are available regarding the long- term prognosis of this disease, particularly that beyond 10 years. Here we describe a patient with primary duodenal follicular lymphoma who was treated with single- agent rituximab and followed- up for 15 years. It is notewor- thy that the disease relapse occurred not in the duode- num, but in the stomach and rectum. This case underscores the importance of surveillance of not only the duodenum but the entire intestinal tract during the follow- up of primary duodenal follicular lymphoma cases. Case Report A 41-year- old woman underwent esophagogas- A 41-year- old woman underwent esophagogas- troduodenoscopy for screening as a routine medical checkup. Multiple white nodules were detected in the F Acta Med. Okayama, 2015 Vol. 69, No. 5, pp. 301ﾝ306 CopyrightⒸ 2015 by Okayama University Medical School. Case Report http: // escholarship.lib.okayama-u.ac.jp / amo/ Received December 4, 2014 ; accepted May 7, 2015. ＊ Corresponding author. Phone: ＋ 81ﾝ86ﾝ235ﾝ7219; Fax: ＋ 81ﾝ86ﾝ225ﾝ5991 E-mail : yoshino0901@yahoo.co.jp (A. Seki) Conflict of Interest Disclosures: No potential conflict of interest relevant to this article was reported.