Focal myositis: a localized form of polymyositis?

We describe an additional case of focal myositis presenting as a painful pseudotumor of the lower leg. Surgical biopsy showed typical features of myositis; the disease improved spontaneously, without clinical or biological abnormalities. Focal myositis can remain a localized process, but in some cases it can become an authentic polymyositis. These generalized forms are associated early with elevated erythrocyte sedimentation rate and/or muscular enzymes.