Nemaline bodies in spinal progressive muscular atrophy. An autopsy case.

Numerous nemaline bodies were demonstrated in the pectoralis major muscle of an autopsy case of a 52-year-old woman, who died of respiratory failure after having suffered from spinal progressive muscular atrophy for 1 year. Rod-like structures ultrastructurally indistinguishable from classical nemaline bodies were abundant in both normal-appearing and atrophic myofibers of the pectoralis major muscle but not in the appendicular skeletal muscles. Morphometric analysis of spinal anterior horn cells clearly showed severe depopulation of somatic motor neurons in the lower cervical cord segments. The present case may provide further support for the neurogenic nature of nemaline body formation.