C68-14 Atypical Presentation of Disseminated Mycobacterium Kansasii as an Endobronchial Lesion

Abstract Introduction Mycobacterium kansasii is a slow-growing, photochromogenic nontuberculous mycobacterium (NTM) known to cause pulmonary infections resembling tuberculosis, particularly in immunocompromised hosts such as patients with HIV/AIDS. Pulmonary disease is the most common manifestation, though disseminated or endobronchial involvement is uncommon. We present a rare case of disseminated M. kansasii infection manifesting as an endobronchial lesion in a patient with well-controlled HIV. Case Report A 33-year-old man with HIV (CD4 401 cells/µL, viral load undetectable) on antiretroviral therapy, end-stage renal disease on hemodialysis, heart failure with reduced ejection fraction, and prior pulmonary embolism/deep vein thrombosis presented with hypotension and seizure-like activity. Chest CT revealed multiple right upper and middle lobe nodules and a new 7 mm endobronchial nodule in the bronchus intermedius, raising concern for malignancy, infection, or septic emboli.Bronchoscopy demonstrated a friable endobronchial lesion (Figure 2). Forceps and needle biopsies were obtained, and a right middle lobe bronchoalveolar lavage (BAL) was performed. Endobronchial ultrasound-guided lymph node sampling included the subcarinal node. The patient remained asymptomatic and stable throughout hospitalization, without respiratory distress or hypoxia, and was discharged pending results.BAL and fine-needle aspirate cultures later revealed 4+ acid-fast bacilli, identified as M. kansasii. Cytology showed no malignancy, granulomas, or fungal/viral inclusions. The findings confirmed disseminated M. kansasii infection.The patient was started on rifabutin (substituted for rifampin due to apixaban use), ethambutol, and azithromycin, with a planned 12-month course. His antiretroviral regimen required no adjustment, and he was counseled on adherence and potential drug interactions. Discussion Although M. kansasii typically presents as chronic pulmonary infection, disseminated disease or endobronchial involvement remains rare, especially in HIV-positive patients with preserved CD4 counts. Bronchoscopic identification and culture remain key for diagnosis. Early recognition and tailored antimicrobial therapy are critical, as delayed treatment may lead to progressive pulmonary or systemic involvement. Rifabutin-based regimens offer an effective alternative in patients with contraindications to rifampin. Conclusion This case highlights an atypical endobronchial presentation of disseminated M. kansasii infection in a patient with controlled HIV. Clinicians should maintain a high index of suspicion for NTM infections in immunocompromised hosts with unexplained pulmonary nodules or airway lesions, even when HIV is well managed. This abstract is funded by: None