Histopathological findings in Becker-type muscular dystrophy.

Muscle biopsy specimens from 14 patients with Becker-type muscular dystrophy were analyzed to investigate possible neurogenic factors underlying the histopathological changes. Group atrophy, pyknotic nuclear clumps, and angular small fibers were seen respectively in 71%, 85%, and 100% of the cases. In one biopsy specimen, notable type grouping was observed. A prominent finding was the appearance of groups of regenerating fibers in biopsy specimens from younger patients. Fiber degeneration was present in only 57% of the cases. While myopathic features predominated in some biopsy specimens, others were compatible with denervation. It is not possible to give an answer to the question whether the changes are basically myopathic or neurogenic (or both), but evidence is growing that a neurogenic component may play a part in the pathogenesis of the disease.