[Polymyositis associated with peripheral nerve lesion: clinico-pathological investigation of 8 cases]

Polymyositis with peripheral nerve lesion are rare. The study of eight cases of polymyositis with some peripheral lesion, pathologic investigation of muscle biopsy of all patients and biopsy of sural nerve in six cases were reported. Age: 19-52 (average 34) yrs.

4mo-10 (average 4) yrs. They showed symmetric weakness and tenderness of the proximal muscles, peripheral hypoesthesia and hypo even areflexia. Electrophysiological parameters showed myogenic lesion in 8 cases and neurogenic in 3 cases. Pathological (light and electron-microscopic) findings coincide with acute and chronic myositis, consisting of focal necrosis of muscle fiber, monocyte infiltration, myofibril regeneration, hyperplasia of interstitial vessels and fibrous tissue in muscle biopsy of 8 cases; mild to moderate loss of density of myelinated fibers, mostly thin myelin sheath and demyelinating changes, axonal degeneration also, mainly loss of unmyelinated fiber, perivascular monocyte and macrophages in sural nerve biopsy of six cases. The aforementioned clinical and pathological findings suggest that involving both muscle and nerve be able to primary. No primary course involving nerve has been found, except in only one case with coexisting SLE, another case six months later carcinomatous myositis was diagnosed, but there are no evidence of vasculitis and ischemic neuropathy.