43例孤立性浆细胞瘤临床病理和免疫表型研究

目的观察孤立性浆细胞瘤的临床病埋表现和免疫表型，探讨其诊断和鉴别诊断。方法对43例孤立性浆细胞瘤（含髓外浆细胞瘤24例，骨孤立性浆细胞瘤19例）作临床病理观察及随访，SP法免疫表型分析（CD20、CD79a、PC、IgK、Igλ、IgA、IgD、IgE、IgG和IgM）。结果24例髓外浆细胞瘤患者年龄3～70岁（平均年龄49岁），男女比2．5：1，22例发生于鼻腔或鼻副窦，肺、扁桃体各1例。19例骨孤立性浆细胞瘤患者年龄36～72岁（平均53岁），男女比1：1，发生于脊柱8例，骨盆3例，锁骨、肋骨、股骨各2例，桡骨、胫骨各1例。均表现为局部新生物。组织学特征为：①粘膜坏死和溃疡形成，肿瘤细胞呈弥漫性浸润，②分化成熟的瘤细胞形似正常浆细胞，分化不成熟的瘤细胞形似中心母细胞；③间质少，血管丰富或形成血湖；④淀粉样物质沉积。免疫表型：①43例之瘤细胞均表达CD79a，均不表达CD20，其中41例呈PC阳性，②43例均呈Ig轻链限制性表达（31例λ，12例κ）IgG型39例，IgA型1例，IgG／IgM双表达2例，IgA／IgG双表达1例。结论孤立性浆细胞瘤有特征性的组织病理学改变，诊断时高分化者应注意与反应性增生、粘膜相关淋巴瘤相区别；低分化者应与大细胞淋巴瘤、恶性黑色素瘤和低分化癌相区别。

Solitary Plasmacytoma: A Clinicopathologic and Immunophenotypic Analysis of 43 Cases

OBJECTIVE: To investigate the clinicopathologic and immunophenotypic features of solitary plasmacytoma and discuss the diagnosis and differential diagnosis of the tumor. METHODS: Clinicopathological study and follow up study were made on 43 cases of solitary plasmacytoma, including 24 cases of extramedullary plasmacytoma (EMP) and 19 cases of solitary plasmacytoma of bone (SPB). Immunohistochemical staining was performed by SP method using antibodies CD20, CD79a, PC, Ig kappa, Ig lamda, IgA, IgD, IgE, IgG and IgM. RESULTS: Rgarding EMP, the male/female ratio is 2.5 to 1, the age ranges from 3 to 70 years (mean 49). Clinically, the neoplasms of 22 cases were located in nasal cavity or nasosinus, 2 cases were located in lung and tonsil respectively. Rgarding SPB, the male/female ratio is 1:1, the age ranges from 36 to 72 years (mean 53). Clinically, the neoplasms of 8 cases were located in vertebrae, 3 cases in pelvis, 6 cases in clavicle, rib and femur respectively, 2 case in radius and tibia respectively. Histopathological examination revealed tumor cells diffuse infiltration with necrosis and ulceration; the well-differentiated tumor cells were similar to the normal plasmacyte in shape; the poorly-differentiated tumor resembled centroblasts; there were a few interstitial tissues with plenty of vessels or formation of blood lakes; and there was deposition of amyloid materials. Immunophenotypic analysis showed that all tumor cells were positive for CD79a and negative for CD20; that plasma cell marker (VS38C) was expressed in 41 cases; that light chain restriction was detected in all 43 cases( 31 for lamda and 12 for kappa), and that heavy chain expression was detected in 39 for IgG, 1 for IgA, 2 for both IgG and IgM, and 1 for IgA/IgG. CONCLUSION: The special histopathology in this group of solitary plasmacytomas is presented. The well-differentiated tumors should be distinguished from reactive plasmacytosis and MALT. And, when poorly-differentiated solitary plasmacytomas were tentatively diagnosed, large cell lymphoma, melanoma and poorly differentiated carcinoma should be considered in differential diagnosis.