The pathology of type II skeletal muscle glycogenosis. A light and electron-microscopic study.

Muscle biopsies were obtained from three infants under the age of 12 mth, each of whom was diagnosed as having Pompe's disease. The biopsies revealed a severe vacuolar myopathy with accumulation of large amounts of PAS positive material within the muscle fibres, changes similar to those in adult cases of the disease. In addition large amounts of metachromatic material were found within the muscle fibres in all three cases and in two of them scattered, rather sparse perivascular lymphocytic infiltrates were seen in the interstitial tissue. Review of material previously obtained from two adult cases showed no accumulation of metachromatic material in the older case and only moderate amounts in the younger. However, dense interstitial lymphocytic infiltrates were seen in the former, some concentrated around small vessels. These observations suggest that the pathogenesis of the muscle disorder in acid maltase deficiency may not depend on abnormal glycogen storage only.