Pyomyositis presenting as septic arthritis. A report of 2 cases.

Two cases of pyogenic infection of skeletal muscle presented in a fashion that initially suggested a diagnosis of septic arthritis. One infection was caused by Staphylococcus aureus, but the other was caused by Streptococcus pyogenes, which is rarely implicated in pyomyositis. We note that the number of reported cases of pyomyositis in temperate climates has increased in recent years.