[Clinicopathological features and BRAF V600E and MYD88 L265P mutation status of nodal marginal zone lymphoma].

Objective: To investigate the clinicopathological features as well as BRAF V600E and MYD88 L265P mutation status of nodal marginal zone B cell lymphoma (NMZL). Methods: Thirty-two cases of NMZL were diagnosed from September 2009 to February 2021 at the Henan Provincial People's Hospital and Peking University School of Basic Medical Sciences. The clinicopathologic characteristics were obtained and analyzed. BRAF V600E and MYD88 L265P mutation status were identified using PCR and Sanger sequencing, respectively. Results: There were 20 males and 12 females patients with a median age of 69 years (ranging 36-82 years). The most prevalent clinical manifestation was multiple lymph nodes enlargement in head and neck (22/32, 68.8%), followed by inguinal (12/32, 37.5%), axillary (11/32, 34.4%), mediastinum (5/32, 15.6%) and retroperitoneal lymph nodes (4/32, 12.5%). Most of the patients were in Ann Arbor stage Ⅰ/Ⅱ (21 cases). The morphologic features included diffuse (24/32, 75.0%), nodular (5/32, 15.6%), interfollicular (2/32,6.3%) and perifollicular (1/32,3.1%) types. The tumor cells showed monocyte-like, centrocyte-like, small lymphocyte-like and plasma cell-like differentiation. Immunophenotyping revealed diffuse expression of CD20 in all tumor cells, whereas CD43 (11/32, 34.4%), bcl-2 (20/32, 62.5%), MNDA (13/32, 40.6%) and CD5 (2/32, 6.3%) were partially expressed. Ki-67 proliferation index varied from 10% to 40%. BRAF V600E mutation was found in two cases (2/32, 6.3%), but MYD88 L265P mutation was not detected. Eighteen patients survived and three died at the end of follow-up period which ranged 6 to 110 months. Conclusions: The morphologic features of NMZL varies across individuals, it should be differentiated from various B-cell lymphomas; however immunological biomarkers with high specificity for NMZL are still lacking. No MYD88 L265P mutation is found in NMZL. Some cases may harbor BRAF V600E mutation and yet the prevalence remains indeterminate; further researches are warranted.目的： 探讨淋巴结边缘区B细胞淋巴瘤（NMZL）临床病理学特点及BRAF V600E和MYD88 L265P基因突变情况。 方法： 收集2009年9月至2021年2月河南省人民医院病理科及北京大学医学部病理学系诊断的NMZL 32例，分析其临床病理学特点，聚合酶链反应（PCR）检测BRAF V600E基因及Sanger测序法检测MYD88 L265P基因突变情况。 结果： 患者男性20例，女性12例，中位年龄69岁（范围36~82岁），临床表现为多发淋巴结肿大，头颈部淋巴结最多见（22/32，68.8%），其次为腹股沟（12/32，37.5%）、腋窝（11/32，34.4%）、纵隔（5/32，15.6%）、腹膜后淋巴结（4/32，12.5%）。患者多处于Ann Arbor分期Ⅰ/Ⅱ期（21例）。形态学表现为弥漫型（24/32，75.0%）、结节型（5/32，15.6%）、滤泡间型（2/32，6.3%）及滤泡周型（1/32，3.1%）的生长模式，肿瘤细胞呈单核细胞样、中心细胞样、小淋巴细胞样及不同程度的浆细胞样分化。免疫表型：肿瘤细胞弥漫表达CD20，部分表达CD43（11/32，34.4%）、bcl-2（20/32，62.5%）、MNDA（13/32，40.6%）、CD5（2/32，6.3%），Ki-67阳性指数10%~40%。2例（2/32，6.3%）BRAF V600E突变，所有病例MYD88 L265P均无突变。随访时间为6~110个月，18例生存，5例死亡。 结论： NMZL形态多样，缺乏诊断特异性免疫标志物，需与多种B细胞淋巴瘤相鉴别。NMZL无MYD88 L265P突变，可伴有BRAF V600E突变，其突变率还需进一步大宗病例进行研究。.