[Thoracic actinomycosis. Apropos of 5 cases]

Described for the first time by Bradshaw in 1846, actinomycosis is a rare, slowly progressing disease associated with the development of anaerobic bacteria of the Actinomyces genus. It predominates in males and is actively encouraged by poor buccal and dental hygiene and by overall decline of defence mechanisms. Thoracic lesions constitute 15 to 20% of the cases and seem to be relatively increasing. Apart from fistulization to the skin, physical examination usually does not show much; only the presence of yellow grains suggests the diagnosis. Radiography is often misleading, suggesting tuberculosis or cancer. Ultrasonography and, chiefly, computerized tomography are the best methods to evaluate the extension of the disease to the pleura, the chest wall and the mediastinum. The final diagnosis is more often supplied by pathological examination than by bacteriology, which is frequently negative. Treatment is facilitated by the fact that Actinomyces is sensitive to antibiotics, notably to penicillin which still is the first choice drug. A well-conducted treatment will give satisfactory results, but sequelae of retractile fibrosis may be disabling.