摘要目的：探讨心脏外横纹肌瘤的临床病理学特征、鉴别诊断及其生物学行为。方法回顾性复习1997年1月至2014年5月间诊断的9例心脏外横纹肌瘤的临床资料、光镜形态和免疫学表型，结合文献复习探讨其临床病理学特点及鉴别诊断。结果9例病例中男性5例，女性4例。平均年龄为37畅6岁，范围为2岁3个月～59岁。头颈部7例，胸壁和阴道各1例。临床上多表现为浅表软组织内或黏膜下结节状或息肉状肿块，平均直径3畅2 cm。组织学上，4例为成人型横纹肌瘤，由分化良好、紧密排列的大多边形或圆形横纹肌母细胞组成，胞质丰富，嗜伊红色或透亮状；3例为黏液型胎儿型横纹肌瘤，由不成熟的骨骼肌纤维、梭形细胞和原始间叶细胞组成，细胞间为大量黏液样基质，1例为中间型胎儿型横纹肌瘤，由排列致密的分化性横纹肌母细胞组成，无黏液样基质；1例为生殖道型，黏膜下可见长梭形或宽带状横纹肌母细胞，散在分布于疏松的纤维结缔组织内。免疫组织化学标记显示，瘤细胞主要表达结蛋白、肌特异性抗原和肌红蛋白，部分病例表达肌生成素，1例中间型胎儿型横纹肌瘤表达平滑肌肌动蛋白。随访2个月～17年，1例于术后6个月复发。结论心脏外横纹肌瘤是一种显示不同程度骨骼肌分化的良性间叶性肿瘤，偶可发生局部复发，特别是切除不干净时，熟悉其各种亚型的临床和病理学特点有助于与胚胎性横纹肌肉瘤的鉴别诊断。

abstractsObjective To investigate the clinicopathologic characteristics , differential diagnosis and biological behavior of extracardiac rhabdomyoma.Methods Nine cases of extracardiac rhabdomyoma diagnosed between January of 1997 and July of 2014 were reviewed.The clinical , pathologic and immunohistochemical profiles were evaluated.Results There were 5 males and 4 females at diagnosis with age ranging from 2 years and three months to 59 years (mean, 37.6 years).Sites included the head and neck region (7 cases), chest (1 case ) and vagina wall (1 case).Clinically, most cases manifested as a subcutaneous nodule or as a submucosal polypoid lesion with a mean diameter of 3.2 cm.Histologically , 4 were adult-type rhabdomyoma characterized by tightly packed large round or polygonal rhabdomyoblasts with abundant eosinophilic to clear cytoplasm; 3 were myxoid variant of fetal rhabdomyoma composed of immature myofibrils, spindled and primitive mesenchymal cells embedded in a myxoid background , 1 was an intermediate form of fetal rhabdomyoma consisting of densely arranged differentiated myoblasts with little myxoid stroma;1 was a genital rhabdomyoma composed of elongated or strap-like myoblasts scattered in loose fibrous connective tissue.By immunohistochemistry , they showed diffuse and strong positivity for desmin , MSA and myoglobin with variable expression of myogenin.A case of intermediate type also stained forα-smooth muscle actin.Follow up data ( 2 months ~17 years ) showed local recurrence in one patient 6 months after surgery.Conclusions Rhabdomyoma is a distinctively rare benign mesenchymal tumor showing skeletal muscle differentiation , which may occassionally recur if incompletely excised.Familiarity with its clinical and morphological variants is essential to avoid misdiagnosing this benign lesion as embryonal rhabdomyosarcoma.