Radiologic Subtypes and Treatment Outcome of Unclassifiable Type Mycobacterium avium Complex Pulmonary Disease

ABSTRACT

Methods@#Ninety-six patients with unclassifiable type MAC-PD who initiated a macrolidecontaining regimen from 2001 to 2020 were identified at a tertiary referral center in South Korea. Among these 96 patients, 1-year culture conversion rate was analyzed for 48 patients who received standard treatment (three-drug oral-antibiotic combination with or without an injectable agent) for ≥ 1 year. @*Results@#The mean age of the 96 patients was 65.4 ± 10.8 years, and 72.9% of them were male. These patients were classified into four major radiologic subtypes; the most common subtype was the focal cavity subtype (n = 31, 32.3%), followed by the focal mass or nodule (n = 23, 24.0%), consolidation upon emphysema (n = 21, 21.9%), and bronchiolitis (n = 21, 21.9%) subtypes. For the 48 patients who received standard treatment for ≥ 1 year, the overall rate of culture conversion at 1-year was 93.8%. All patients in the focal cavity subtype and focal mass or nodule subtype categories achieved 1-year culture conversion. Additionally, 1-year culture conversion rate was 92.9% in consolidation upon emphysema subtype and 75.0% in bronchiolitis subtype. @*Conclusion@#Unclassifiable type MAC-PD can be radiologically further categorized into four major radiologic subtypes. The treatment outcome of all of these subtypes seems to be favorable.