Rimmed vacuoles.

Rimmed vacuoles (Dubowitz and Brooke 1973) have been found in 12 cases with various neuromuscular diseases and are considered to be autophagic in nature. They consisted of multilaminated membranous structures accompanied by glycogen granules, dense bodies, and amorphous, granular, and fibrillar material. The contents of the vacuoles were regarded as having partially dissolved out of the vacuoles in cryostat sections but some were plastered along the walls of the vacuoles and were depicted by the staining procedures for light microscopy. The "lined vacuoles" described by Carpenter et al. (1978) in inclusion body myositis closely agree with the rimmed vacuoles in respect of histochemical and ultrastructural features.