Focal eosinophilic myositis--a rare cause of pseudotumor.

Idiopathic focal eosinophilic myositis is a rare benign pseudotumor of skeletal muscle of unknown cause, characterized by focal eosinophilic infiltration of striated muscle. It can mimic a soft tissue sarcoma clinically and on gross examination of the specimen. Microscopic examination establishes the diagnosis. It is important to recognize this pseudosarcomatous lesion so as to spare the patient from anxiety.