RESUMO
Actinomycosis is a bacterial infection due to Gram-positive bacteria of the Actinomyces genus. The authors describe two cases: one of them occurred in a woman with a clinical presentation of a right submandibular indurative mass. After surgery, histological examination showed a granulomatous tissue with many actinomycetes. The second case was observed in a man admitted to hospital with a diagnosis of pulmonary heteroplastic lesion. Also in this case, histological examination showed many actinomycotic colonies. Actinomycosis is an uncommon disease. Establishment of definite diagnosis requires a high index of suspicion in all cases of relapsing cervical lesions. Pulmonary actinomycosis is a rare diagnosis; respiratory physicians should be aware of this important differential when investigating patients for persistent pulmonary shadowing.