[Pulmonary actinomycosis simulating Tobias-Pancoast tumor].

Actinomycosis is a rare infection that may involve several organs. Thoracic involvement is uncommon (10-20%). This article describes the case of a 33 year-old patient, HIV negative, complaining of burning pain in the left posterior chest radiating to the left upper arm and reduced strength and paresthesias. The CT scan showed a mass in close contact with the chest wall. Following a thoracotomy, observation verified a solid pulmonary lesion adhered to the left upper lobe, infiltrating the posterior thoracic wall and apex of the cavity with rich vascularization. An incisional biopsy of the lesion and microbiological study revealed actinomycosis.