C68-10 Endobronchial Mass in an Immunocompromised Patient: An Uncommon Presentation of Mycobacterium Avium-intracellulare Complex

Abstract Introduction Pulmonary coinfections in advanced HIV/AIDS can present diagnostic and therapeutic challenges, especially in the setting of recent opportunistic pneumonia. We present a rare case of overlapping pulmonary infections with Mycobacterium avium-intracellulare complex (MAI) and probable invasive pulmonary aspergillosis (IPA) in a patient with AIDS and persistent hypoxia following Pneumocystis jirovecii pneumonia (PJP). Case Description We report a 55-year-old male with newly diagnosed HIV/AIDS (CD4 count 31 cells/μL, HIV viral load 167,000 copies/mL) who presented with hypoxic respiratory failure. He was diagnosed with PJP and treated successfully with a 21-day course of high-dose trimethoprim-sulfamethoxazole (TMP-SMX) and prednisone, followed by initiation of antiretroviral therapy (bictegravir/emtricitabine/tenofovir alafenamide). He was discharged on prophylaxis with daily TMP-SMX and weekly azithromycin. Despite clinical improvement, he remained oxygen-dependent. High-resolution CT revealed a right middle and lower lobe consolidating mass concerning for infection or malignancy. Bronchoscopy with bronchoalveolar lavage (BAL) and endobronchial biopsy demonstrated positive galactomannan antigen (index 1.90, up from 0.78) and culture growth of MAC. Cytology was negative for malignancy. Although elevated galactomannan suggested possible invasive pulmonary aspergillosis, the absence of classic imaging features such as the crescent sign and pathology findings was suggestive that MAC was the primary pathogen. He was treated with voriconazole for aspergillosis while prophylactic azithromycin was continued, with plans for full MAC therapy. Follow-up PET/CT showed interval resolution of the mass with residual focal scarring and bronchiectasis. No evidence of malignancy was identified. The patient’s respiratory status gradually improved with ongoing ART, oxygen therapy, and antimicrobial management. Discussion This case highlights the complexity of managing overlapping opportunistic pulmonary infections in advanced HIV/AIDS. The coexistence of PJP, MAI, and probable invasive pulmonary aspergillosis within a short clinical course is rare and underscores the need for a broad differential diagnosis when pulmonary masses persist following initial therapy. Although BAL galactomannan index was elevated, the absence of classic radiographic features such as the crescent sign and pathology more consistent with MAC complicated interpretation. Ultimately, the pulmonary mass resolved with antimicrobial therapy, supporting infection rather than malignancy as the underlying process. Careful balancing of antifungal and antimycobacterial regimens was required, particularly given the risk of QT prolongation with voriconazole and azithromycin coadministration. This abstract is funded by: n/a