[Lung actinomycosis with chest wall involvement].

Actinomycosis is an uncommon suppurative granulomatous chronic infection that may involve several organs. Lung infection is usually related to immunodepression and poor oral hygiene. Cases of thoracic involvement are rare (10 - 20%) and only 12% of such cases affect the chest wall. This report describes the case of a 26-year-old HIV-negative patient without comorbidities or respiratory complaints who presented a very painful, progressively growing infrascapular mass, with local phlogistic signs and no local trauma, and persistent fever. It had been progressing for three months. The initial diagnosis was neoplasia of chest wall soft tissue. However, incision biopsy in this mass produced a red wine-colored gelatinous secretion containing yellowish granules suggestive of actinomycosis, which was later confirmed by anatomopathological examination. Ciprofloxacin was instituted empirically because of cephalosporin allergy. There was an excellent clinical response to external drainage and the prescribed medication. Over the course of 18 months of follow-up, there was no disease recurrence.