RESUMO
Actinomycosis is a chronic, granulomatous suppurative disease caused by Actinomyces species. Actinomyces is an anaerobic, gram positive organism that requires special techniques for culture and isolation. Actinomycosis is characterized by formation of multiple abscesses, draining sinuses, abundant granulations (sulfur granule) and dense fibrous tissue. The three major clinical presentations include the cervicofacial, thoracic, and abdominal regions. Since A. israelii is a normal inhabitant of the oral cavity, to make a definitive diagnosis it must be recovered from closed tissue spaces, draining sinuses, or abscesses, or it must be shown to be invasive in histopathologic sections. The drug of choice is penicillin. Because of the dense fibrous tissue surrounding the colonies of organisms and the concentration of organisms in clusters, high doses of pharmacologic agents must be used for long periods, and radical surgical excision should accompany antibiotic therapy if possible. We report three cases of abdominal actinomycosis, preoperatively impressed as appendicitis and pelvic abscess, which was diagnosed by a histological study of operative specimens. The possible pathogenic mechanisms causing clinical symptoms are discussed.