[Thoracic actinomycosis--a case report].

BACKGROUND: Actinomycosis is caused by a variety of gram-positive anaerobic or microaerophilic rods belonging to the genus Actinomyces or Propionibacterium. The production of suppurative abscesses or granulomas that eventually develop draining sinuses are hallmarks of the disease. We describe the case of a 55 year old smoker who presented himself 4 months ago with right thoracic pain and an unproductive cough. He developed a warm, red mass in the lower part of the right thorax. We performed an ultrasound guided needle aspiration and the pathologic examination revealed typical sulfur granules and masses of neutrophils in the aspirate. After surgical resection of the abscess and under high-dose therapy with penicillin G the further course of disease was uneventful. CONCLUSIONS: Although uncommon, thoracic actinomycosis should always taken into account in the differential diagnosis of chronic inflammatory processes that involve the pulmonary parenchyma or pleural space.