Department of Hematopathology and Hematology, Hospital Clinic, Institut d'Investigacions Biomèdiques August Pi I Sunyer (IDIBAPS), University of Barcelona, Barcelona, Spain.
Am J Surg Pathol. 2013 Feb;37(2):272-81. doi: 10.1097/PAS.0b013e31826cb1d1.
Histologic transformation of low-grade B-cell lymphoma to diffuse large B-cell lymphoma is associated with poor prognosis. Although plasma cell differentiation is common in these lymphomas, an overt plasmablastic transformation (PBL-T) has been only rarely reported. We report 6 cases of PBL-T occurring in 3 chronic lymphocytic leukemias (CLL) and 3 follicular lymphomas. Five patients were men, and the mean age was 65 years (range, 52 to 72 y). None of them had history of immunodeficiency. In 3 cases the PBL-T occurred 34 to 85 months after the initial diagnosis, and in 3 it was detected simultaneously with the small cell component at diagnosis. All patients received chemotherapy after transformation, and 4 died 4 to 24 months after this diagnosis. In 3 cases, PBL-T occurred in an extranodal site. All PBL-Ts had immunoblastic morphology with admixed plasma cells, were CD20 and PAX5 negative, expressed λ light chain, and 5 were CD138 positive. All cases were negative for HHV8, and only 1 PBL-T was Epstein-Barr virus positive. Evidence of a clonal relationship between the small cell and PBL-T components was found in 5 cases. In 2 CLL cases, both components had 13q deletions, and in all follicular lymphoma cases both components harbored the t(14;18) translocation. MYC translocations were observed in 2 cases transformed from a CLL. In conclusion, PBL-T expands the clinicopathologic spectrum of the transformation of low-grade B-cell lymphomas. These transformed tumors are clinically, histologically, and phenotypically similar to primary plasmablastic lymphomas, but they are not associated with immunodeficiency and rarely have Epstein-Barr virus infection or MYC alterations.
低级别 B 细胞淋巴瘤向弥漫性大 B 细胞淋巴瘤的组织学转化与预后不良相关。虽然浆细胞分化在这些淋巴瘤中很常见，但明显的浆母细胞转化（PBL-T）很少见。我们报告了 6 例发生于 3 例慢性淋巴细胞白血病（CLL）和 3 例滤泡性淋巴瘤中的 PBL-T。5 例患者为男性，平均年龄为 65 岁（范围，52 岁至 72 岁）。他们均无免疫缺陷病史。3 例 PBL-T 发生于初始诊断后 34 至 85 个月，3 例同时在诊断时发现小细胞成分。所有患者在转化后均接受化疗，4 例在该诊断后 4 至 24 个月死亡。3 例 PBL-T 发生于结外部位。所有 PBL-T 均具有免疫母细胞形态，混合有浆细胞，CD20 和 PAX5 阴性，表达 λ 轻链，5 例 CD138 阳性。所有病例均为 HHV8 阴性，仅 1 例 PBL-T 为 EBV 阳性。在 5 例病例中发现小细胞和 PBL-T 成分之间存在克隆关系。在 2 例 CLL 病例中，两者均有 13q 缺失，在所有滤泡性淋巴瘤病例中，两者均具有 t（14;18）易位。2 例由 CLL 转化而来的病例观察到 MYC 易位。总之，PBL-T 扩大了低级别 B 细胞淋巴瘤转化的临床病理谱。这些转化肿瘤在临床、组织学和表型上与原发性浆母细胞淋巴瘤相似，但与免疫缺陷无关，很少发生 EBV 感染或 MYC 改变。
