A 61-year-old man with muscle aches and persistently elevated serum creatin
e kinase had aggregates of randomly oriented, rhomboidal or rectangular pro
tein crystalline inclusions in the sarcoplasm of type II fibers. Immunochem
ical studies showed strong reactivity of the inclusions to tubulin antibodi
es, suggesting that these unique crystalline inclusions may be a consequenc
e of altered synthesis, processing, or degradation of tubulin.