[Thoracic actinomycosis masquerading as a central bronchial carcinoma]

A 41-year-old cachectic woman (weight 42.7 kg, height 1.65 m) was admitted to hospital because a chest radiogram had suggested a left central bronchial carcinoma. Four days previously she had noted for the first time a firm elastic swelling parasternally in the fourth intercostal space. This swelling was directly aspirated by needle after bronchoscopic results had been nonspecific. Surprisingly, pus containing actinomyces filaments was aspirated. Computed tomography confirmed a paramediastinal abscess, 8 x 5 x 6 cm, which had infiltrated into the left thoracic wall. The abscess was incised and drained. After treatment for two weeks, initially with three times daily 10 mega penicillin G intravenously, followed by erythromycin, 500 mg twice daily for 12 weeks, the thoracic actinomycosis was no longer demonstrable radiologically and by ultrasound. It is suggested that in any unclear pulmonary infiltrate without evidence of tuberculosis or carcinoma actinomycosis should be included in the differential diagnosis.