Histopathological findings in the biopsied muscle of a juvenile type III glycogenosis.

We report a case of juvenile type III glycogenosis that was confirmed by histopathological and biochemical studies. The histopathological findings consisted of vacuoles, periodic acid-Schiff positive materials, type 2B fiber deficiency, mildly positive acid phosphatase reaction and intensely positive non-specific esterase reaction. It is suggested that the enzyme reactions may be related to membrane-bound sacs containing glycogen.