Focal myositis--neurogenic phenomenon?

[focal myositis]

We report four cases of focal myositis . The patients , three men and one woman , had painful muscle hypertrophy , affecting four different sites . MRI confirmed the muscle enlargement and oedema . Electromyography revealed evidence of acute and chronic denervation in all four cases . Muscle biopsy was available in three and confirmed features suggestive of focal myositis . Based on our patient material , we suggest that chronic nerve irritation , such as compression , can lead to muscle hypertrophy which , when prolonged , provokes fibre necrosis and secondary inflammation . Our finding in four patients having hypertrophy involving four different sites , leads us further to suggest that this may be the common mechanism behind focal myositis .