15例头颈部梭形细胞/硬化性横纹肌肉瘤的临床病理分析

目的:探讨头颈部梭形细胞/硬化性横纹肌肉瘤（spindle cell/sclerosing rhabdomyosarcoma,SRMS/ScRMS）的临床病理学特征、免疫表型及预后。方法:回顾性分析15例头颈部SRMS/ScRMS患者临床、病理资料以及免疫组织化学检测结果。结果:15例患者（10例SRMS,5例ScRMS）中,男7例,女8例;年龄2个月~57岁,平均20.1岁。颞下窝5例,上颌骨软组织2例,舌2例,其余分别发生于咀嚼肌区、下颌软组织、翼颌间隙、腮腺区、颈部、唇部各1例。临床均表现为逐渐增大的肿块。肿块直径约1.5~20 cm,平均6.3 cm。组织学上,10例SRMS 主要由具有轻度非典型性的梭形细胞组成,呈交叉束状排列,散在于梭形细胞之间,可见少量横纹肌母细胞。5例ScRMS均以大量玻璃样变的硬化性基质为特征,类似原始的小圆细胞组成,以条索状、列兵样、梁状、微腺泡状和假血管样等多种方式排列。免疫组织化学标记显示,肿瘤细胞均弥漫表达vimentin和desmin,MyoD1呈弥漫及多灶性表达,12例表达myogenin,均不表达S100、HMB-45、Caldesmon、CK和CD34。15例患者均采用手术治疗,其中3例术后辅以化疗和/或放疗。随访4~205个月,平均59个月。5例无病生存,9例死亡,1例失访。结论:头颈部SRMS/ScRMS好发于儿童和青少年,且预后较差。熟悉其形态特征和免疫表型,有助于识别这类少见的横纹肌肉瘤亚型,并与其他梭形细胞及以间质硬化为主的肿瘤相鉴别。

Clinicopathological analysis of 15 patients with spindle cell and sclerosing rhabdomyosarcomas in the head and neck region

PURPOSE: To study the clinicopathologic features,immunophenotype and prognosis of spindle cell and sclerosing rhabdomyosarcomas（SRMS/ScRMS） in the head and neck region. METHODS: The clinical, pathological and immunohistochemical features were evaluated in 15 cases of SRMS/ScRMS in the head and neck region. RESULTS: Fifteen cases of spindle cell and sclerosing rhabdomyosarcomas（10 SRMS and 5 ScRMS）in the head and neck region were retrieved from the pathological archive, which were diagnosed and reviewed by two independent pathologists,with the classification based on current WHO criteria as SRMS/ScRMS. Seven cases were male and 8 were female. Their ages ranged from 2 months to 57 years (median 20.1 years). The most common anatomic location of the neoplasms was the infratemporal fossa (n=5), followed by the soft tissue of maxilla (n=2),the tongue (n=2), as well as the masseteric region, the soft tissue of mandible, the pterygomandibular space, the parotid region, the neck and the lip. Tumor size varied from 1.5 to 20 cm (median 6.3 cm). Histologically, all SRMS of 10 were mainly composed of cellular bands and fascicles of low-grade atypical spindle-shaped tumor cells with a variable number of spindled or polygonal rhabdomyoblasts. All ScRMSof 5 were characterized by the presence of large amounts of heavily hyalinized matrix, mimicking osteoid or chondroid tissue . The tumor cells were composed predominantly of primitive small round cells which were arranged in diverse growth patterns, including fascicular, trabecular, microalveolar and pseudovascular structures. Immunohistochemically, all the tumor cells of SRMS/ScRMS showed diffuse expression of vimentin and desmin. MyoD1 immunostaining was diffuse to multifocally positive. Twelve cases showed myogenin positive immunostaining, but all cases were negative for S100, HMB-45, Caldesmon, CK and CD34. All the patients underwent surgical resection, and only 3 patients had chemotherapy and radiotherapy after surgery as adjuvant treatment. Completed clinical follow-up information was available from 14 patients, ranging from 4 to 205 months（median 59 months）, of which 5 cases had no-evidence of disease, but 9 cases died of recurrence or distant metastasis after surgery. CONCLUSIONS: SRMS/ScRMS of the head and neck region has a predilection for children and adolescents that may be associated with unfavorable outcomes. Familiarity with its morphological features and immunophenotype may help to distinguish this distinct variant of rhabdomyosarcoma from variety of lesions with abundant sclerosing matrix.