Proliferative myositis: value of imaging.

Imaging findings in a 52-year-old woman with proven proliferative myositis are described. US revealed preservation of continuous muscle bundles and patchy areas of hyperechogenicity, containing hypoechoic lines. MRI showed at T2-w sequences an ill-defined, hyperintense, intramuscular lesion, containing isointense lines. Subtotal enhancement, a nonenhancing geometrical web, and fascial enhancement were noted. In patients with painful growing masses, US and MRI correlation may suggest the diagnosis of proliferative myositis leading to biopsy, thus avoiding mutilating surgery.