ABSTRACT
A case of pyomyositis of right pyriformis and iliacus muscle in a healthy 13 year old male patient is presented and discussed. Pyomyositis is a primary acute bacterial infection of large skeletal muscles, associated with abscess formation. Since pyomyositis has been reported mainly in tropical countries and is rare in temperate climates, the name 'tropical myositis' is often used. Outside the tropics, pyomyositis is often associated with immune compromised state, and vigorous muscle acivity may have a role in some cases of pyomyositis. In this case, thirteen year old healthy boy developed severe right buttock pain after vigorous gymnasium activity and was treated with acutpucture, then showed high fever and aggrevation of pain. This case was thought to be associated muscle injury due to vigorous gymnasium activity and transient bacteremia following cutaneous acupuncture. He was treated with ultrasono guided needle aspiration and parenteral antibiotics successfully.