十二指腸球部病変が診断の契機となった消化管原発follicular lymphomaの1例

Primary Follicular Lymphoma of the Gastrointestinal Tract Detected by Bulbar Lesions in the Duodenum, Report of a Case

要旨　患者は70歳，女性．自覚症状なし．定期検診の上部消化管内視鏡検査で十二指腸球部に白色顆粒状病変の集簇を認め，同部位からの生検でfollicular lymphoma（FL）, Grade 1と診断された．十二指腸下行部に異常はなかった．ダブルバルーン小腸内視鏡検査で空腸にも十二指腸球部と同様の病変を認めた．一方，回腸終末部には広基性扁平隆起性病変を認め，表面はやや結節状で周辺の健常粘膜とほぼ同じ色調を呈していた．生検では空腸および回腸病変ともにFL, Grade 1と診断された．腹部CT所見で傍大動脈周囲のリンパ節腫大を認め，Lugano国際分類Stage II₂と診断した．治療はrituximabを併用したR-CHOP療法を6クール施行し，完全寛解した．消化管原発FLは十二指腸下行部の白色顆粒状病変として発見されることが多いが，本症例のように十二指腸球部に病変を認める症例はまれである．

　A 70-year-old asymptomatic woman was underwent esophagogastroduodenoscopy（EGD）in a regular-interval examination after endoscopic mucosal resection for gastric adenoma. EGD revealed multiple whitish granular lesions in the duodenal bulb, but no abnormal finding was observed in the descending portion of the duodenum. The biopsy specimens gathered from the lesions showed infiltration of atypical lymphoid cells with lymphoid follicles. From these histological findings and immunohistochemical study, she was diagnosed as having follicular lymphoma（grade 1） according to the World Health Organization classification. A double balloon enteroscopy revealed clusters of whitish granular lesions in the jejunum, which resembled in the bulbar lesions. On the other hand, low-growing protruded lesions with nodular surface were recognized in the terminal ileum, and the color of the lesions was not whitish but akin to that of the adjacent normal mucosa. The biopsy specimens taken from the lesions in the jejunum and the terminal ileum were diagnosed as follicular lymphoma（grade 1）. Abdominal CT revealed nodal involvement in the mesenteric and para-aortic regions. Finally, the patient was diagnosed as stage II2 primary follicular lymphoma（grade 1）. She underwent 6 courses of chemotherapy with a regimen of cyclophosphamide, doxorubicin, vincristine, and prednisolone including rituximab（R-CHOP）. Complete regression was achieved, and recurrence of follicular lymphoma has not been recognized 9 months after chemotherapy.

　The descending portion of the duodenum is the most frequently affected region in primary follicular lymphoma of the gastrointestinal tract. This patient is thought to be a rare case because of detection through by the bulbar lesions in the duodenum.