Spindle cell rhabdomyosarcoma in adults:a clinicopathologic study of nine cases

　　成人梭形细胞横纹肌肉瘤9例临床病理学分析

　　Abstract：Purpose To study the clinicopathological features, immunophenotype and differential diagnosis of spindle cell rhabdomyosarcoma in adults (SRMS).Methods The clinical,pathologic and immunohistochemical features were evaluated in 9 cases of SRMS in adults.Results Nine cases of SRMS in adults were retrieved from the pathological archive of this hospital. 7 cases were male and 2 were female. Patients age ranged from 20 to 80 years (median,45 years). The head and neck region,including the right mandible, pharyngeal portion, nasopharynx, and left maxillary,was the most commonly affected area, accounting for 44% of the cases, followed by forearm, waist, thigh, leg and testis(1 case each). Tumor size varied from 2 to 14 cm (median 5.9 cm).Histologically, all the tumors were mainly composed of cellular bands and fascicles of atypical spindlE-shaped tumor cells with a variable number of spindled or polygonal rhabdomyoblasts.In addition, focal areas reminiscent of interstitial sclerosing were presented in 2 cases, and pseudovascular structures were noted in 2 cases, loosely myxoid stroma were detected in 1 case and small solid areas with mild pleomorphic tumor cells were present, but lacking bizarre pleomorphic rhabdomyoblasts. Immunohistochemically, the tumor cells were positive for vimentin, desmin, CD99 and MyoD1; Myogenin and MSA were positive in most of the cases (6/9 and 7/9 each); The remaining antibodies(S-100, CD34,CK and HMB-45) were all negative. Follow-up information was available in all the cases, ranged from 6 months to 4 years, revealed paravenous metastases of the peritoneal cavity in one patient with testis tumor and liver metastases in one patient with leg tumour. 4 patients developed local recurrences and 2 patients died of the disease.Conclusions SRMS is a rare neoplasm in adults,and most commonly occurs in male with preferential involvement in the head and neck region. It appears a more aggressive clinical course in adults. Morphologically, SRMS in adults should be differentiated from other spindle cell tumors.

　　摘要:目的 探讨成人梭形细胞横纹肌肉瘤(spindle cell rhabdomyosarcoma,SRMS)的临床病理学特征、免疫表型和鉴别诊断.方法 回顾性分析9例成人SRMS的临床资料、病理学形态和免疫组织化学标记结果.结果 9例患者中7例男性,2例女性.年龄20～80岁,平均45岁.发生于头颈部4例,包括右下颌、咽部、鼻咽部和左上颌,占总数的44%.前臂、腰部、大 腿、小腿、睾丸分别1例.均表现为逐渐增大的肿块.肿块直径2～14 cm,平均5.9 cm.组织学上主要由具有轻度非典型性的梭形细胞组成,呈交叉的束状排列,散在于梭形细胞之间有少量的梭形或多角形的横纹肌母细胞.在2例局灶区域可见明 显的间质硬化, 2例局灶区域可见假血管瘤样结构,1例散在少量疏松黏液样区域,在1例可见局灶区域瘤细胞呈轻度的多形性,但不见奇异核的横纹肌母细胞.免疫组织化学标记 显示,梭形细胞表达vimentin、desmin、CD99和MyoD1,多数表达myogenin和MSA(分别为6例和7例),均不表达S- 100、CD34、CK和HMB-45.术后随访6个月～4年,发生于睾丸患者有腹腔静脉旁转移,发生于小腿者有肝转移.4例复发,2例死亡.结论 成人SRMS少见,好发于男性,头颈部是最好发部位,具有较强的侵袭性行为.形态学上应与多种梭形细胞肿瘤相鉴别.