Thoracopulmonary actinomycosis: the masquerader.

Thoracopulmonary actinomycosis can mimic various lung pathologies such as bronchogenic carcinoma, tuberculosis and fungal pneumonia, to name but a few. The common causative agent is Actinomyces israelii. The disease is successfully diagnosed only if there is a high index of suspicion and a thorough evaluation with multidisciplinary involvement. We present a case of thoracopulmonary actinomycosis in a young immunocompetent man who did not have any predisposing illness, and who was treated initially for pulmonary tuberculosis. He showed good response to injection crystalline penicillin, which was later changed to oral amoxicillin.