[Thoracic actinomycosis].

Thoracic actinomycosis is a rare disease without characteristic clinical signs. Approximately 90% of patients suffering from thoracic actinomycosis have undergone diagnostic and therapeutic procedures based on a wrong diagnostic hypothesis (malignancies 35-44%, other pulmonary disorders 33-35%). The opportunities for a timely and adequate diagnosis by the use of clinical examination, laboratory studies, microbiology studies, radiologic imaging or invasive measures are limited. In 85%, thoracic actinomycosis has not been identified prior to thoracotomy, open biopsy and histological examination. Based on a wrong diagnostic hypothesis, resective thoracic surgery according to the principles of oncologic surgery can hardly be avoided. We report on a 43-year-old male suffering from actinomycosis of the left hemithorax. Clinical signs, differential diagnosis, treatment and clinical course are described. The role of surgery in the treatment protocol of thoracic actinomycosis is discussed. In pulmonary and pleural disorders of unknown origin, differential diagnosis should include thoracic actinomycosis as early as possible. Due to the considerably high mortality rate of untreated disease, the outcome of thoracic actinomycosis can only be improved by a timely and combined employment of surgical and antibiotic therapy.