青少年型皮肌炎的病理特点(附6例报告)

目的 探讨青少年型皮肌炎的皮肤和骨骼肌微血管病理改变规律。方法 6例患儿的发病年龄在7～14岁之间，主要表现为急性或亚急性起病的四肢肌肉无力，伴随面部和颈部皮肤水纹样皮疹。对所有患者的肌肉进行活检，其中2例患者进行皮肤活检，肌肉标本进行常规组织学和酶组织化学染色，皮肤和肌肉标本进行电镜检查。结果 6例患者均存在典型皮肌炎的肌肉病理改变特点，表现为以肌束衣为主的炎细胞浸润和束周分布的肌纤维空泡变性和再生现象。非特异性酯酶染色显示小血管和毛细血管内皮细胞深染。电镜检查发现皮肤毛细血管内皮细胞坏死消失后残留的基底膜结构和细胞降解产物，在部分成熟毛细血管内皮细胞的胞浆内可见管网包涵体，该包涵体不出现在小血管坏死和再生的内皮细胞以及平滑肌细胞内。相同改变规律的微血管病变也出现在骨骼肌内。结论 皮肤具有和骨骼肌相同的微血管病理改变规律。内皮细胞损伤是青少年型皮肌炎微血管病的主要病理改变。显然青少年型皮肌炎是血管内皮细胞病。束周肌纤维病变为继发于微血管内皮细胞病变的缺血性损伤。

Pathological characteristics of juvenile dermatomyositis ,six cases reported

Objectives To investigate pathological features in juvenile dermatomyositis,especially microangiopathy in skin and skeletal muscles.Methods 6 children with juvenile dermatomyositis with onset of disease between 7~14 years old were studied.Muscle biopsies were performed in all cases.Skin biopsies were made in 2 of them.The muscle and skin specimens were investigated with histological, enzymhistochemical,as well as electromicroscopical examination.Results Histological studies revealed typical myopathological changes of dermatomyositis with inflammatory infiltration predominantly in perimysium and perifascicular arrangement of degenerated and regenerated muscle fibers.In compare with smooth muscle cells and pericytes in microvascular walls,non special esterase staining showed markedly positive in endothelial cells,which presented ultrastructurally degeneration and regeneration.In both skeletal muscle and skin tissue,the electron microscopy demonstrated identical tubuloreticular inclusions in capillary mature endothelial cells.The inclusions were failed to be found in necrotic and regenerative endothelial cells,smooth muscle cells and pericytes.Conclusions The skin and muscle presentes similar pathological changes in capillary endothelial cells in juvenile dermatomyositis.We speculates that juvenile dermatomyositis may be a microvascular endotheliopathy.Cutaneous pathological change as well as muscle fiber re and degeneration are likely due to ischaemic lesion secondary to microvascular endotheliopathy.