Pulmonary actinomycosis presenting as a mass-like consolidation.

Pulmonary actinomycosis presented as a mass-like consolidation. The diagnosis was not established until clinical suspicion prompted special staining of the pathology material. Response to antibiotics was facilitated by a removal of the airway plug through bronchoscopy. Airway obstruction may contribute to the prolonged medical treatment of pulmonary actinomycosis.