报告多发性肌炎、皮肌炎81例。其中46例做肌肉活检,见不同程度肌纤维变性坏死,炎性细胞浸润。11例超微结构观察到淋巴细胞侵入肌纤维基底膜下,肌丝断裂,空泡样变,Z线消失,肌细胞再生。除肌纤维病变外,11例发现血管壁增厚,管腔狭窄甚至闭塞。6例神经活检发现周围神经脱髓鞘及血管内膜增生。提示肌纤维损伤存在不同的病理机制。 81 cases reported polymyositis, dermatomyositis. 46 cases of muscle biopsy, see varying degrees of myofibrosis necrosis, inflammatory cell infiltration. Eleven cases of ultrastructure were observed lymphocytes invade the muscle fiber basement membrane, myofilament rupture, vacuolar degeneration, Z line disappeared, muscle cell regeneration. In addition to muscle fiber lesions, 11 cases of vascular wall thickening, stenosis or occlusion. 6 cases of nerve biopsy found that peripheral nerve demyelination and intimal hyperplasia. Tip muscle fiber damage there are different pathological mechanisms.