Myositis as an unusual presentation of secondary syphilis.

Myositis is a complication of many infectious and noninfectious processes. Secondary syphilis is an uncommon cause of myositis, and, therefore, the diagnosis may be delayed. We describe a man with human immunodeficiency virus infection presenting with diffuse muscle injury secondary to syphilis. He had complete resolution of all signs and symptoms after treatment with intravenous penicillin.