[A SURGICAL CASE OF MYCOBACTERIUM KANSASII LUNG DISEASE MIMICKING PRIMARY LUNG CANCER].

We report a rare surgical case of a solitary pulmonary nodule due to Mycobacterium kansasii. A 59-year-old man was admitted to our hospital for examination of an abnormal shadow in the left upper lobe incidentally found on a chest radiogram. Computed tomography of the chest showed that the nodule was located in the left segment 1+2 and was irregularly shaped with a diameter of 35 mm. Thoracic fluorine-18 fluoro-deoxy-glucose positron emission tomography showed a high metabolic pulmonary lesion, with a maximum standardized uptake value of 5.1, consistent with findings for lung cancer. A bronchoscopy was performed to establish the diagnosis of lung cancer; however, it failed to show malignant cells. Because we could not confirm the diagnosis by bronchoscopic examination, video-assisted thoracoscopic surgery was performed. The intraoperative rapid diagnosis of the nodule was epithelioid cell granuloma. Smear test of the resected specimen was positive for acid-fast bacilli, and a culture was also positive for mycobacteria, which were identified as Mycobacterium kansasii. Antibiotic treatment for M. kansasii infection was administered for a year after the surgical resection. Few cases of Mycobacterium kansasii infection present with solitary pulmonary nodules.