Disseminated Mycobacterium avium complex (MAC) infection is a well-recognized opportunistic disease in patients with advanced HIV infection; however, endobronchial involvement is exceedingly rare. Here, we report a case of disseminated MAC infection presenting with progressive endobronchial lesions associated with immune reconstitution inflammatory syndrome (IRIS). A 32-year-old man living with HIV who had discontinued antiretroviral therapy (ART) presented with severe immunosuppression (CD4+ count: 23 cells/µL) and was diagnosed with disseminated MAC infection based on lymph-node biopsy and positive blood cultures. Antimycobacterial therapy was initiated in conjunction with ART resumption. During the treatment course, rifabutin-induced immune-mediated thrombocytopenia and amikacin-related ototoxicity occurred, necessitating multiple modifications of the treatment regimen. Despite virologic suppression and immunologic recovery, progressive left hilar lymphadenopathy and a rapidly enlarging polypoid endobronchial mass with intense fluorodeoxyglucose uptake on positron emission tomography-computed tomography developed, raising suspicion for HIV-associated malignancy. Bronchoscopic biopsy revealed granulomatous inflammation with abundant acid-fast bacilli, confirming endobronchial MAC disease consistent with IRIS. Serial bronchoscopic evaluations demonstrated gradual regression of lesions with continued antimicrobial therapy. This case illustrates the diagnostic challenge of distinguishing MAC-associated IRIS from malignancy and underscores the essential role of bronchoscopy with histopathological confirmation. Long-term, individualized management is required because clinical improvement may paradoxically coincide with airway involvement and treatment-limiting adverse events.
Motojima-Muto et al. (Sat,) studied this question.