Solitary Pulmonary Nodules Caused by Mycobacterium tuberculosis and Mycobacterium avium Complex

Few studies have compared the clinical and radiographic findings of tuberculomas to those of solitary pulmonary nodules (SPNs) caused by Mycobacterium avium complex (MAC). We retrospectively analyzed clinical and radiographic findings from 26 patients with tuberculomas and 15 patients with SPNs caused by MAC. Median SPN size was 22 mm. In 26 patients (63%), the SPN was detected during a routine health checkup or evaluation of organs other than lungs. Patients with SPNs due to MAC were slightly older (median = 59 years) compared with those with tuberculomas (median = 50 years; P = 0.044). When we compared computed tomography (CT) features between patients with tuberculomas and patients with MAC, no significant differences were found in SPN location or the presence of calcification, cavitation, central low attenuation, and the satellite lesions. Although the maximum standardized uptake values were slightly higher in patients with SPNs due to MAC (median = 8.5) compared with those with tuberculomas (median = 2.2), this difference was not significant (P = 0.053). Of the 15 patients with SPNs due to MAC, 10 were initially diagnosed with “tuberculoma” and administered antituberculosis medication. MAC pulmonary disease should be considered in the differential diagnosis of SPNs, even when encountered in geographic regions with a high prevalence of pulmonary tuberculosis.