目的： 探讨十二指肠型滤泡性淋巴瘤（duodenal-type follicular lymphoma, DFL）的临床病理学特征及预后。方法： 回顾性分析17例DFL患者的临床特点、内镜表现、病理学特征及治疗方案，并进行随访。结果： 17例DFL患者中，男性8例，女性9例，男女比为1∶1.125，中位年龄为58岁（33~67岁），其中13例DFL患者是在常规体检中发现，内镜下多表现为颗粒状增生。DFL发生在十二指肠者有15例（88.2%），且全部位于十二指肠降段；单发病灶15例，多发病灶2例。内镜下，见病变位于黏膜层或黏膜下层，呈清楚或隐约的“膨胀性”生长，可见滤泡样结节，结节内由中心细胞样细胞和散在中心母细胞样细胞组成，相当于经典型滤泡性淋巴瘤的1级或2级。肿瘤细胞表达CD20、CD79a、CD10、BCL6及BCL2，9例患者的CD21染色显示滤泡树突网在肿瘤性滤泡周边密集、浓染，而在中央淡染、稀疏，Ki-67低表达。4例患者行第二代基因测序检测，其中3例共同检测到CREBBP基因变异。14例患者未经任何治疗，疾病无进展；1例行局部肠段切除，术后未行化疗和放疗，未复发；1例接受化疗加利妥昔单抗治疗，病变完全消退。结论： DFL多为单发病灶，镜下表现类似经典型滤泡性淋巴瘤1级或2级，较特殊的免疫表型是CD21常在肿瘤性滤泡周边更密集、深染，具有惰性生物学行为。

Objective: To investigate the clinicopathological features and prognosis of duodenal-type follicular lymphoma (DFL). Methods: The clinical features, endoscopic appearances, pathological features, and treatments of 17 patients with DFL were retrospectively analyzed and followed up. Results: Among the 17 cases of DFL, there were 8 males and 9 females, with a male-to-female ratio of 1∶1.125. The median age was 58 years (33-67 years). Among them, 13 patients with DFL were found in routine physical examination, and most of them showed granular hyperplasia under endoscopy. Among the cases, 15 (88.2%) occurred in the duodenum, and all were located in the descending part of the duodenum. There were 15 cases of single lesions and 2 cases of multiple lesions. Under the microscope, the lesions were located in the mucosal layer or submucosal layer, with a clear or vague “expansive” growth pattern and visible follicular nodules. The nodules were composed of centrocyte-like cells and scattered centroblast-like cells, equivalent to grade 1 or 2 of classical follicular lymphoma. The tumor cells expressed CD20, CD79a, CD10, BCL6, and BCL2. CD21 staining of 9 cases showed that the follicular dendrite network was densely stained around the neoplastic follicles, but lightly stained and sparse in the center. Ki-67 expression was low. Four cases underwent second-generation gene sequencing, among which three cases had detected CREBBP gene mutations. Fourteen cases did not receive any treatment, and disease did not progress. One case underwent local intestinal segment resection without postoperative chemotherapy or radiotherapy and did not relapse. One case received chemotherapy and rituximab treatment, and the lesion completely disappeared. Conclusions: Most of DFL lesions are single lesions with microscopic manifestations similar to those of typical follicular lymphoma grade 1 or grade 2. The special immunophenotype is CD21, which is often more dense and deeply stained around the neoplastic follicles, and has inert biological behavior.