摘要目的 探讨多形性横纹肌肉瘤(PRMS)的临床病理学特征、鉴别诊断及生物学行为.方法 回顾性复习2005至2012年间44例PRMS的临床资料、镜下形态和免疫学表型,并分析其预后.结果 男性33例,女性11例,主要发生于成年人,特别是40岁以上的中老年人(31/44,70.5％),平均年龄和中位年龄分别为51岁和55岁,年龄范围为2 ～ 85岁.22例肿瘤位于四肢(50.0％),16例位于躯干(36.4％),5例位于内脏(11.4％),1例位于头颈部(2.2％).临床上,患者多以生长迅速的无痛性肿块就诊.肿瘤直径为2.0～17.0 cm,平均7.3 cm.组织学上,40例肿瘤显示多形性肉瘤形态,类似未分化多形性肉瘤/恶性纤维组织细胞瘤,但多数病例中可见数量不等的嗜伊红色多形性横纹肌母细胞.另4例肿瘤主要由条束状排列的梭形瘤细胞组成,瘤细胞间散在的多形性横纹肌母细胞.免疫组织化学标记显示,所有病例均弥漫强阳性表达结蛋白(41/41,100％),多数病例尚表达肌生成素(18/32,56.3％)、肌调节蛋白(10/21,47.6％)和肌特异性肌动蛋白(21/29,72.4％),而平滑肌肌动蛋白多为阴性.29例(65.9％)获得随访资料,12例带瘤生存,17例无瘤生存,中位无瘤生存和总生存时间分别为6.0个月(平均9.1个月)和8.0个月(平均11.2个月).13例(44.8％)肿瘤进展(4例复发,9例转移),中位肿瘤进展时间为6.0个月(平均5.9个月).结论多形性肉瘤中的嗜伊红色多形性细胞对PRMS的诊断具有提示性作用.结蛋白弥漫强阳性、平滑肌肌动蛋白阴性有助于PRMS的诊断,并可与多形性平滑肌肉瘤等肿瘤相鉴别.PRMS偶可发生于儿童或青少年,但需注意勿将间变性横纹肌肉瘤误诊为PRMS.PRMS属高度恶性肉瘤,预后较差.

abstractsObjective To investigate the clinicopathologic characteristics,differential diagnosis and biologic behaviors of pleomorphic rhabdomyosarcoma (PRMS).Methods The clinical findings,pathological features and immunophenotypes were reviewed in 44 cases of PRMS (encountered during the period from 2005 to 2012).The clinical outcome was analyzed.Results There were 33 males and 11 females with age ranging from 2 to 85 years (mean,51 years; median,55 years).Of 44 tumors,22 occurred in the extremities (50.0％),16 in the trunk (36.4％),5 in the internal organs (11.4％),and 1 in the head and neck (2.2％).Histologically,40 tumors showed features of pleomorphic sarcoma with striking resemblance to undifferentiated pleonorphic sarcoma (UPS)/malignant fibrous histiocytoma (MFH).However,variable amount of pleomorphic rhabdomyoblasts (PRMB) were identified in most cases.The remaining 4 tumors were composed predominantly of fascicles of spindle cells with interspersed PRMBs.Immunohistiochemically,tumor cells showed diffuse staining of desmin (41/41,100％),with variable expression of myogenin (18/32,56.3％),MyoD1 (10/21,47.6％) and MSA (21/29,72.4％),whereasα-SMA was negative in most cases.Follow-up data (range,2 to 51 months) available in 29 cases showed 12 patients were alive with unresectable or recurrent disease and 17 patients were alive with no evidence of disease.The median disease-free and overall survivals was 6.0 months (mean,9.1 months)and 8.0 months (mean,11.2 months) respectively.Thirteen patients (44.8％) exhibited progression of disease with recuTence in 4 cases and metastasis in 9 cases.The median interval to progression was 6.0months (mean,5.9 months).Conclusions The presence of pleomorphic cells with strong eosinphilic cytoplasm in a pleomorphic sarcoma is suggestive of a PRMS.Diffuse,strong expression of desmin and negative staining for α-SMA further facilitate the diagnosis of PRMS and its differential diagnosis from pleomorphic leiomyosarcoma.Although PRMS may affect children or adolescents,it should be cautious not to misdiagnose anaplastic rhabdomyosarcoma as PRMS.PRMS is a high-grade sarcoma with a poor prognosis.