Isolated inflammatory myopathy with rimmed vacuoles presenting with dropped head.

We describe an unusual case of inflammatory myopathy with rimmed vacuoles associated with dropped head syndrome. Muscle biopsy in our patient revealed variations in fiber size with fiber necrosis and regeneration, accompanied by many rimmed vacuoles and areas of endomysial cell infiltration. Electron microscopy demonstrated autophagic vacuoles and tubulofilamentous inclusions. This myopathy can cause dropped head syndrome in a subgroup of patients.