[Bronchial carcinoma and actinomycosis: a dangerous trap].

A 60 year old male patient was admitted to hospital with pulmonary and cerebral abscesses. A percutaneous lung biopsy under CT scanning showed actinomycosis. After 4 weeks antibiotic therapy with ceftriaxone and metronidazole there was an improvement in the pulmonary lesion but new cerebral lesions appeared. A neurosurgical cerebral biopsy showed evidence of metastatic squamous carcinoma, probably of pulmonary origin. The diagnosis had been delayed by the presence of the actinomycosis. His general condition did not permit anti-tumour treatment and the patient soon afterwards. In the presence of pulmonary actinomycosis an associated malignancy should be excluded.