Typical nemaline bodies presenting in a patient with polymyositis

A 66-year-old woman presented with a progressive myopathy affecting the proximal limbs and unusual pathological findings of nemaline bodies on muscle biopsy. Histological examination demonstrated that the bodies were mainly located in the subsarcolemmal region of atrophic fibers, exhibited strong immunoreactivity with antibodies to both alpha-actinin and m-actin, and had a typical lattice-like appearance at higher magnification on electron microscopy. These findings were the same as those for nemaline myopathy. The patient responded to steroid therapy, but relapse occurred after steroid was discontinued. Given the clinical criteria of polymyositis, we believe that the occurrence of nemaline bodies in our patient should be interpreted primarily as an epiphenomenon of primary myopathy.