儿童Burkitt淋巴瘤累及骨髓的病理学诊断与鉴别诊断

Pathological diagnosis of pediatric Burkitt lymphoma involving bone marrow

目的探讨儿童Burkitt淋巴瘤（BL）的骨髓病理学特点及鉴别诊断。方法回顾性分析20例儿童BL的临床与病理学资料，其中行外周血及骨髓穿刺涂片20例、骨髓活检及免疫组织化学EliVision法染色18例、流式细胞学检查16例及MYC基因荧光原位杂交（FISH）检测11例。结果19例外周血涂片（1例外院会诊病例无外周血资料）和20例骨髓涂片均可见肿瘤细胞，比例分别为2．O％～81．0％和46．0％～98．5％，肿瘤细胞形态特点为胞质内可见数量不等的空泡。其中具有骨髓活检的18例均以异型淋巴细胞增生为主，胞体中等大，具有多个细小核仁；未见“星空”现象；免疫组织化学染色CD20、PAX．5、CD10阳性，CD34、末端脱氧核糖核苷酸转移酶（TdT）、bcl-2、CD3阴性，Ki-67阳性指数均〉95％。20例中16例有流式细胞学检测结果，均检出异常细胞，比例为40．8％-96．2％，免疫表型为CD19、CD20、CD10、FMC7、CD22阳性，TdT、CD5阴性。8例κ、7例入阳性，1例为κ和λ双阴性。11例患者骨髓涂片MYC基因FISH检测结果为10例阳性，1例阴性。结论儿童BL具有独特的骨髓病理学特点，在骨髓涂片中，肿瘤细胞胞质可见空泡，而骨髓活检中肿瘤细胞胞质空泡难以见到，且缺乏淋巴结等组织标本中所具有的典型的“星空”现象，需结合免疫表型及遗传学改变等结果综合诊断。主要与儿童弥漫性大B细胞淋巴瘤（DLBCL）及介于DLBCL和BL之间不能分类的B细胞淋巴瘤鉴别。

Objective To investigate pathologic and differential diagnostic features of pediatric Burkitt lymphoma （BL）. Methods A total of 20 cases of pediatric BL were retrospectively reviewed for their clinical and pathologic profiles. Bone marrow aspiration specimens were available in all cases and bone marrow biopsies were available for immunohistochemical study in 28 cases. Flow cytometry study was available in 26 cases~ MYC translocation by F2SH method was performed in 11 cases. Results Atypical lymphocytes with cytoplasmic vacuoles were found in bone marrow smears in all 20 cases and peripheral blood films in all 19 available cases. The bone marrow biopsies showed infiltration by uniform medium-sized atypical lymphocytes with multiple small nuc/eoli but without the starry-sky pattern in all 18 cases . Immunohistochemistry showed the following results in all 18 cases： positive for CD20, PAX-5, CD20, CD34 and TdT, but negative for bcl-2 and CD3 with Ki-67 〉95%. Flow cytometry showed CD29 ＋ CD20 ＋ CD20 ＋FMC7 ＋CD22 ＋TdT-CD3- in 26 cases, including κ ＋ in 8 cases, λ. ＋ in 7 cases, and κ-λ- in 2 case. MYC gene rearrangement by FISH was observed in 20 of the 12 cases. Conclusions The histopathology of BL is distinct, including atypical lymphocytes with cytoplasmic vacuoles in bone marrow aspirate, lack of starry-sky patternin bone marrow biopsy. Generally, the diagnosis should be made with a combined immunophenotype and FISH approach. Pediatric BL must he distinguished from DLBCL and B-cell lymphoma, unclassifiable, which has intermediate features between DLBCL and Burkitt lymphoma.