Desmin myopathy: a multisystem disorder involving skeletal, cardiac, and smooth muscle.

Myopathy associated with desmin-type intermediate filaments is an uncommon disorder of skeletal and/or cardiac muscle. The present study focuses on a 28-year-old man with generalized muscular atrophy, cardiomyopathy, and intestinal malabsorption and pseudo-obstruction. Abundant sarcoplasmic granular and filamentous aggregates that were ultrastructurally continuous with Z lines or dense bodies and exhibited intense immunostaining for desmin were present throughout the skeletal musculature, myocardium, and smooth muscle of the intestine. Moreover, neurofilament-immunoreactive axonal spheroids were identified in the spinal cord and roots. These widely distributed findings illustrate the multisystemic character of desmin myopathy, which in this instance first adds intestinal smooth muscle involvement to its already known skeletal and cardiac muscle manifestations. The additional presence of neurofilament aggregates in the spinal cord and roots constitutes an extremely rare conjunction of intermediate filament pathology of the neuromuscular system.