A case of pulmonary nocardiosis diagnosed by percutaneous aspiration

A 71-year-old man complained of mild dyspnea, and his chest X-ray showed a cavitating lesion accompanied by infiltrative changes in the right middle lobe. Percutaneous aspiration revealed numerous gram-positive and acid-fast branching rods. Morphological examination and biochemical tests of the colonies confirmed the diagnosis of pulmonary nocardiosis caused by nocardia asteroides. The patient was treated successfully with sulfamethoxazole-trimethoprim. It has been reported that approximately half of the patients with pulmonary nocardiosis have immunodeficiency, but our patient had no underlying disease. This disease has no characteristic clinical features, so diagnosis is difficult. As nocardia may involve the central nervous system leading to a poor prognosis, early diagnosis and prompt treatment are required to improve survival.