"Reducing body"-like inclusions in skeletal muscle in childhood-onset acid maltase deficiency.

Unusual inclusions with some of the features of "reducing bodies" were encountered in the skeletal muscle biopsy of a 2.5-year-old boy with childhood-onset acid maltase deficiency. The biopsy revealed a vacuolar myopathy with lysosomal storage of glycogen and eosinophilic refractile inclusions in myofibers, which appeared dark blue with the menadione-nitroblue tetrazolium reaction. The significance of the association of inclusions with reducing properties in the setting of acid maltase deficiency is discussed.