骨髓活检组织淋巴瘤的病理诊断和分型

目的 探讨组织形态改变、免疫组织化学、基因重排在淋巴瘤骨髓侵犯的病理诊断和分型中的作用。材料与方法 对62例甲醛固定、石蜡包埋的骨髓活检组织,分别做了组织学、EnVision法观察和免疫球蛋白重链(IgH)基因和TCRγ基因重排检测。结果 慢性淋巴细胞性白血病／小淋巴细胞淋巴瘤(CLL／SLL)的异型淋巴细胞呈小梁间结节状或散在分布,有时可见假滤泡结构。滤泡型淋巴瘤(FCL)表现为结节性小梁旁或小梁间的浸润,结节内小淋巴样细胞松散聚集。淋巴浆细胞性淋巴瘤(LPL)主要为小梁间弥散浸润,在小而圆的淋巴细胞间可见散在数量不等的浆细胞样淋巴细胞。边缘区淋巴瘤(MZL)则见模糊的或界限不清的小梁间或小梁旁结节,一些细胞胞质透明。套细胞性淋巴瘤(MCL)异型细胞小到中等大小,缺乏副免疫母细胞和假滤泡。毛细胞性淋巴瘤(HCL)瘤细胞胞膜多清晰,胞质丰富透明,常形成荷包蛋样表现。霍奇金病可见大核瘤细胞,核仁明显。T-非霍奇金淋巴瘤(NHL)浸润骨髓主要为小梁间间质性散在或弥漫分布,胞质多透明,核有芋艿样或脑回状改变,DLBL造血细胞间体积大的瘤细胞散在或弥漫分布。CD3对T细胞来源、CD20和CD79对B细胞来源淋巴瘤有鉴别诊断价值,cyclin D1和(SD5阳性对MCL具有诊断性价值,bcl-2和CD10阳性则对FCL具有诊断性意义,而CLL／SLL除了(SD20和CD79阳性外,也可CD5和CD23阳性。HCL的瘤细胞CD25强阳性。CD15、CD30和Fascin也适用于骨髓霍奇金病的诊断。骨髓中CLL／SLL,LPL,MZL及DLBL的IgH重排率(80％、60％、66．7％、70％)及T—NHL的TCRγ重排率(66．7％)较高。结论 综合组织形态改变、免疫组织化学和IgH／TCRγ重排检测,有助于淋巴瘤骨髓侵犯的诊断和分型,有助于发现骨髓中为数不多的淋巴瘤细胞。

Pathologic diagnosis and subtyping of lymphoma in bone marrow biopsies using histologic examination, immunohistochemistry and gene rearrangement studies

OBJECTIVE: To assess the value of histologic examination, immunohistochemistry and gene rearrangement studies in the diagnosis and subtyping of lymphoma with bone marrow involvement (BMI). METHODS: Sixty-two formalin fixed, paraffin embedded bone marrow biopsy specimens were studied. Immunohistochemical and immunoglobulin heavy chain (IgH) and T-cell receptor gene rearrangement studies were performed in each case. RESULTS: Chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) demonstrated mainly and interstitial infiltration by dysplastic lymphocytes, with intertrabecular nodular arrangement or in dispersion. Sometimes, pseudofollicles may be noted. A predominantly para- or intertrabecular infiltration by nodules of lymphoma cells was characteristic of follicle center cell lymphoma (FCL) cases. In most lymphoplasmacytoid lymphoma (LPL) cases, there was infiltration by small lymphocytes and plasma cells between bony trabeculae. In marginal zone cell lymphoma (MZL), vague inter- or para-trabecular nodules of polymorphic lymphoma cells with clear cytoplasm might be noted. Small to medium-sized dysplastic lymphocytes, with absence of paraimmunoblasts or pseudofollicles, were the most frequent findings in mantle cell lymphoma (MCL). Hairy cell leukemia (HCL) might be identified by the presence of distinct cell membrane and abundant clear cytoplasm, resulting in a "fried-egg" appearance. Tumor cells with large nuclei and eosinophilic nucleoli were characteristically seen in lymphomatosis diffusa (Hodgkin's disease, HD). In T-cell non-Hodgkin lymphoma with BMI, dispersed or clusters of intertrabecular neoplastic lymphoid cells with clear cytoplasm and gyriform nuclei were often observed. In diffuse large B-cell lymphoma (DLBL), the tumor cells were large and isolated or arranged in diffuse pattern. Immunohistochemically, a panel of markers, including CD3 CD20, and CD79 are valuable for the differential diagnosis of T- and B-cell lymphomas. The neoplastic cells in MCL were cyclin D1- and CD5-positive, while BCL2- and CD10-positivity was characteristic for FCL. CLL/SLL cells might be stained with CD5 and CD23, in addition to CD20 and CD79. CD25 expression might be noted in HCL: the positivity for CD15, CD30 and fascin suggests HD. There was a higher positivity rate for IgH gene rearrangement in CLL/SLL, LPL MZL and DLBL (80%, 60%, 66.7%, 70% respectively) and for T- cell receptor gamma gene rearrangement in T-cell lymphoma (66.7%). CONCLUSION: A combination of histopathology, immunohistochemistry and IgH / T-cell receptor gamma gene rearrangement studies may be of aid to the diagnosis and subtyping of lymphoma with BMI, especially if there is only a small number of tumor cells present in the specimen.