Department of Pathology, Harbor-UCLA Medical Center, 1000 West Carson Street, Torrance, CA 90509, USA.
Exp Mol Pathol. 2011 Feb;90(1):85-90. doi: 10.1016/j.yexmp.2010.10.007. Epub 2010 Oct 19.
Plasmablastic lymphoma (PBL) is an uncommon aggressive lymphoma arising most frequently in the oral cavity of HIV-infected patients. Rare cases of PBL have been reported in extraoral sites, particularly extranodal sites, as well as in immunocompetent patients. We report an unusual case of PBL in a 69-year-old, HIV-negative non-immunocompromised man presenting with generalized lymphadenopathy. To our knowledge, this is the first case of PBL presented as primarily generalized lymphadenopathy in HIV-negative patients. Histologic examinations of cervical, inguinal and axillary lymph nodes demonstrated a neoplastic proliferation of large cells with extensive necrosis. The neoplastic cells formed sheets with a relatively cohesive growth pattern interspersed by small lymphocytes and plasma cells. The large tumor cells expressed MUM1, OCT-2 and BOB.1, and were negative for CD138, CD38, AE1/AE3, melan A, PLAP, S100, vimentin, CD117, CD30, ALK-1, leukocyte common antigen (CD45), T-cell, B-cell and histolytic markers, CD56, CD10 and BCL-6. The proliferation index by Ki-67 immunohistochemistry was approaching 100%. In situ hybridization for Epstein-Barr Virus-encoded RNA (EBER) was positive in large malignant cells. A diagnosis of PBL was made. These findings indicate that PBL should be included in the differential diagnosis of an HIV-negative, immunocompetent patient with generalized lymphadenopathy. The adjacent plasma cells were positive for CD138 and CD38 and show kappa-light chain restriction, but without EBER expression, raising the possibility of a preexisting or concurrent plasmacytoma and that the PBL may be a high-grade transformation from a preexisting plasma cell neoplasm following Epstein-Barr virus infection. Electron microscopy showed numerous circumferential long slender peripheral cytoplasmic projections in the large tumor cells, suggesting that some of the previously reported large B-cell lymphoma with cytoplasmic projections may actually be PBL.
弥漫性大 B 细胞淋巴瘤伴浆母细胞分化 1 例并文献复习
弥漫性大 B 细胞淋巴瘤（diffuse large B-cell lymphoma，DLBCL）是一种常见的侵袭性淋巴瘤，最常发生于 HIV 感染患者的口腔。罕见病例报告弥漫性大 B 细胞淋巴瘤发生于口腔外部位，特别是结外部位，以及免疫功能正常的患者。我们报道了 1 例罕见的发生于无 HIV 感染、非免疫抑制的 69 岁男性患者的弥漫性大 B 细胞淋巴瘤，该患者表现为全身淋巴结病。据我们所知，这是首例表现为主要全身淋巴结病的 HIV 阴性患者的弥漫性大 B 细胞淋巴瘤。颈部、腹股沟和腋窝淋巴结的组织学检查显示，大细胞呈弥漫性坏死的肿瘤性增生。肿瘤细胞形成片状，具有相对凝聚的生长模式，其间散布着小淋巴细胞和浆细胞。大肿瘤细胞表达 MUM1、OCT-2 和 BOB.1，不表达 CD138、CD38、AE1/AE3、melan A、PLAP、S100、vimentin、CD117、CD30、ALK-1、白细胞共同抗原（CD45）、T 细胞、B 细胞和组织溶解标志物、CD56、CD10 和 BCL-6。Ki-67 免疫组化的增殖指数接近 100%。原位杂交检测 Epstein-Barr 病毒编码的 RNA（EBER）在大恶性细胞中呈阳性。诊断为弥漫性大 B 细胞淋巴瘤。这些发现表明，在 HIV 阴性、免疫功能正常的全身淋巴结病患者中，应将弥漫性大 B 细胞淋巴瘤纳入鉴别诊断。邻近的浆细胞 CD138 和 CD38 阳性，κ 轻链受限，但无 EBER 表达，提示存在先前存在或同时存在的浆细胞瘤，弥漫性大 B 细胞淋巴瘤可能是 Epstein-Barr 病毒感染后先前存在的浆细胞肿瘤的高级别转化。电子显微镜显示，大肿瘤细胞的细胞质周围有许多环状细长的周边细胞质突起，提示以前报道的一些具有细胞质突起的大 B 细胞淋巴瘤实际上可能是弥漫性大 B 细胞淋巴瘤伴浆母细胞分化。
