儿童肢体软组织及骨的肌纤维瘤/肌纤维瘤病28例临床病理学分析

Pediatric myofibroma/myofibromatosis of the soft tissue and bone:a clinicopathological analysis of 28 cases

目的探讨儿童肢体软组织及骨的肌纤维瘤/肌纤维瘤病的临床病理学特征、诊断及鉴别诊断。方法收集2011年1月至2018年12月就诊于北京积水潭医院的28例儿童肢体软组织及骨的肌纤维瘤/肌纤维瘤病临床及影像学资料,行光镜观察和EnVision两步法免疫组织化学染色,并复习相关文献。结果28例肌纤维瘤/肌纤维瘤病患儿年龄2个月至14岁,平均7岁。女患儿7例,男患儿21例。12例发生于肢体软组织:手部9例,上臂1例,足部2例。单骨病变14例:股骨8例,胫骨2例,锁骨2例,腓骨1例,桡骨1例。累及多骨的肌纤维瘤病2例。骨内病变影像学显示溶骨性改变。组织学上瘤细胞呈梭形、卵圆形,肌纤维母细胞样,呈显著的细胞密集区与稀疏区交替双相分布,间质黏液样,并见血管周排列。发生骨内可见刺激新骨形成,并伴有炎性肌纤维母细胞瘤及血管瘤样形态。免疫组织化学显示波形蛋白、平滑肌肌动蛋白阳性。经随访,1例在术后11个月复发。结论儿童肌纤维瘤/肌纤维瘤病骨内病变预后较好,具有独特的形态学特征,结合免疫组织化学可与其他梭形细胞肿瘤进行鉴别。

Objective To investigate the clinicopathological features,diagnosis and differential diagnosis of pediatric myofibroma/myofibromatosis of the soft tissue and bone.Methods All cases of pediatric myofibroma/myofibromatosis of the soft tissue and bone diagnosed between January 2011 and December 2018 were retrieved from the surgical pathology records in the Department of Pathology,Beijing Jishuitan Hospital,Beijing,China.Clinical and radiological data were collected.H&E and immunohistochemistry were used to examine histological and immunophenotypic features and to make the diagnosis and differential diagnosis.The relevant literature was also reviewed.Results Twenty-eight cases of pediatric myofibroma/myofibromatosis of the soft tissue and bone were respectively collected.The patients′ages ranged from 2 months to 14 years,with a mean age of 7 years.There were 7 females and 21 males.There were 12 cases located in soft tissue,including the finger(n=9),upper arm(n=1)and foot(n=2).There were 14 cases located in the bone of limb,including the femur(n=8),tibia(n=4),clavicle(n=2),fibula(n=2)and radius(n=1).There were 2 cases of myofibromatosis involving multiple bones.Radiology showed lytic lesions in the bone.The proliferation of spindle-shaped myofibroblasts arranged in fascicles with indistinct eosinophilic cytoplasm and bland nuclei,with no pleomorphism and cytological atypia.The characteristic histologic structure was the biphasic nodular growth pattern with cellular and paucicellular regions.The tumors might arrange in a hemangiopericytoma-like pattern.The stroma varied between dense fibrosis and myxoid changes.The reactive new bone formation and inflammatory cell infiltration also existed.Immunohistochemical study showed that the SMA was positive.The surgical resections were performed.One of the patients had tumor recurrence as a result of 11-month follow-up.Conclusions The pediatric myofibroma/myofibromatosis of the soft tissue and bone is a very rare benign tumor and has a good prognosis.It has a characteristic morphology and its differential diagnosis from other spindle cell tumors could be made with the immunohistochemical analysis.