Fusobacterium pyomyositis of the shoulder after tonsillitis. Report of a case of Lemierre's syndrome.

A case of nontropical pyomyositis is reported in a young male without predisposing factors. The disease was preceded by a tonsillitis, and the presentation initially suggested a septic arthritis of the shoulder. Fusobacterium, a highly unusual pathogen in pyomyositis, was isolated from an abscess in the infraspinatus muscle. The increasing frequency of the disease in areas with a temperate climate and the pathogenesis are discussed. Our case had the classic features of Lemierre's syndrome: invasion of the bloodstream by Fusobacterium species from a tonsillitis.