Multicore myopathy associated with multiple pterygium syndrome and hypertrophic cardiomyopathy.

A boy with multicore myopathy associated with multiple pterygium syndrome and hypertrophic cardiomyopathy is described. Light microscopy of biopsy samples from the skeletal muscle and myocardium revealed multiple cores in the muscle fibers in the former but their absence in the latter. These results suggest that the pathogenesis of the histologic changes might differ between skeletal muscle and myocardium, and that further electron microscopic examination be done on both types of specimen. The prognosis of multicore myopathy is not usually good when cardiac involvement is present.