Pulmonary actnomycosis simulating bronchogenic carcinoma.

During a 2(1/2)-year period, in a 360-bed general hospital, three cases of pulmonary actinomycosis were encountered in men aged 38, 47 and 49 years. In each instance the symptoms, signs and radiological and laboratory findings were such as to warrant a presumptive clinical diagnosis of bronchogenic carcinoma. Thoracotomy was performed in each case. This experience suggests that a definitive clinical diagnosis of bronchogenic carcinoma should not be made without histological evidence. Furthermore, such individuals should have the benefit of exploratory thoracotomy on the off-chance that the pulmonary lesion may be benign and amenable to treatment. Above all it should be remembered that pulmonary actinomycosis can simulate bronchogenic carcinoma to a marked degree.