Disseminated Actinomyces meyeri infection resembling lung cancer with brain metastases.

Thoracic actinomycosis can resemble bronchogenic carcinoma in its clinical presentation and radiographic appearance. We report a case of pulmonary actinomycosis caused by Actinomyces meyeri in which hematogenous dissemination caused multiple brain abscesses resembling metastatic lung cancer. The correct diagnosis was made by thin-needle aspiration of a pleura-based lung mass. The pathogen isolated was further identified with the use of 16S rDNA sequencing. Antibiotic therapy resulted in rapid improvement of the lung lesion; however, the brain lesions required surgical drainage. Antibiotics were continued for more than a year before magnetic resonance images showed complete resolution of the cerebral abscesses.