胃原发性髓外浆细胞瘤临床病理观察

Clinicopathological features of primary extramedullary plasmacytoma of the stomach

目的探讨胃原发性髓外浆细胞瘤(EMP)的临床病理学特征、免疫表型、鉴别诊断、治疗及预后。方法回顾性分析1例胃原发性EMP的临床病理学特征,并复习相关文献。结果患者男性,44岁,因"上腹部持续性胀痛不适半月"而入院。大体上,肿瘤位于胃体部,呈大小8.5 cm×7 cm×2.5 cm的溃疡型肿块。镜下,肿瘤由不同分化阶段的浆细胞组成,弥漫性分布。高倍镜下,肿瘤细胞呈圆形或卵圆形,细胞核圆形或不规则,核偏位,核分裂象易见,肿瘤内散在多核巨细胞。免疫组化:CD138、CD38、MUM1和Lambda(+),而CD20、CD79a、Kappa、CD3、CK、EMA、Cg A、Syn、CD56、HMB45、S100、CD99、MPO等(-),Ki-67增殖指数约80%。结论胃原发性EMP是一种少见的淋巴造血系统恶性肿瘤,确诊需要HE形态结合免疫标记,并应与低黏附性癌、具有浆细胞分化的淋巴造血肿瘤、黑色素瘤、横纹肌肉瘤、神经内分泌癌和胃肠道原始神经外胚层肿瘤等鉴别。

Objective To study the clinicopathological feature,immunophenotype,differential diagnosis,treatment and prognosis of primary extramedullary plasmacytoma of the stomach.Methods The clinicopathologic features of a case of primary extramedullary plasmacytoma of the stomach was analyzed retrospectively,and the relevant literatures were reviewed.Results A 44-year-old male was admitted to hospital due to persistent upper abdominal pain and discomfort for half a month.Grossly,the tumor located in the body of the stomach and was an ulcerative mass measeuring 8.5 cm×7 cm×2.5 cm.Microscopically,the tumor was composed of plasma cells at different stages of differentiation which arranged in diffuse pattern.At high power magnification,the tumor cells were round or oval,the nucles were round or irregular and were peripherally displaced,mitostic figures were easily to be seen,and multinucleated giant cells were scattered within the tumor.Immunohistochemically,the tumor cells were positive for CD138,CD38,MUM1,and Lambda,but negative for CD20,CD79 a,Kappa,CD3,CK,EMA,Cg A,Syn,CD56,HMB45,S100,CD99,and MPO.The proliferative index of Ki-67 was about 80%.Conclusions Primary extramedullary plasmacytoma of the stomach is a uncommon malignant tumor of lymphohematopoietic system.Its definite diagnosis is depended on the combination of HE morphology and immunohistochemical markers.It should be differentiated from poorly cohesive carcioma,lymphohematopoietic tumors with plasma cell differentiation,melanoma,rhabdomyosarcoma,neuroendocrine carcinoma,and gastrointestinal primitive neuroectodermal tumor.