Abstract Introduction Patients with advanced HIV/AIDS, disseminated mycobacterium avium complex (MAC) often present with fevers, weight loss, anemia, and diarrhea. Rarely, it can form pseudotumoral lesions, with pulmonary pseudotumors being especially uncommon. These mass-like lesions can mimic malignancy, often necessitating invasive testing to establish the diagnosis. We report a case of pulmonary MAC pseudotumor with endobronchial obstruction, highlighting this unusual presentation. Case description A 27-year-old male with newly diagnosed HIV/AIDS (CD4 nadir: 40, Viral load: 2 million copies/mL) presented for a clinic visit with progressive weight loss without other respiratory symptoms a month after initiating antiretroviral therapy (ART). Chest CT was performed, revealing a 3.3 × 2.7 × 3.2 cm lobulated right upper lobe (RUL) consolidation, a 3.7 × 2.0 cm right hilar mass and multiple enlarged mediastinal lymph nodes. He underwent CT-guided lung biopsy which showed nonspecific inflammation. Tissue cultures subsequently grew MAC, and the patient was started on azithromycin and ethambutol. Rifamycin was held due to drug interactions with ART. Two months later, the patient was admitted with subacute dyspnea. Repeat imaging showed an interval increase in the size of the RUL lung mass. Bronchoscopy revealed an endobronchial lesion causing a near-complete obstruction of the RUL bronchus. Cryobiopsy of the lesion and debulking was performed along with Endobronchial Ultrasound-guided sampling of lymph nodes. Pathology showed granulomatous inflammation with epithelioid histiocytes, multinucleated giant cells, and inflammatory infiltrates. Tissue AFB cultures from lung and lymph nodes confirmed MAC. This led to a diagnosis of disseminated MAC with pulmonary pseudotumor and treatment was intensified with addition of rifabutin to azithromycin and ethambutol. Discussion Pulmonary pseudotumors are an uncommon manifestation of MAC and can be mistaken for malignancy due to overlapping symptoms and radiologic findings. In patients with advanced AIDS, pulmonary masses often raise concern for malignancies such as lymphoma or bronchogenic carcinoma, which carry vastly different treatment implications and prognosis. Tissue diagnosis with histopathology and microbiologic cultures is therefore critical to avoid misdiagnosis. In this case, the increase in mass size after initiation of antiretroviral and antimycobacterial therapy likely reflected immune reconstitution inflammatory syndrome (IRIS), emphasizing the need to consider the full clinical context before modifying therapy and to include invasive treatment strategies. Clinical implications MAC may present in atypical ways, and pulmonary pseudotumor should be considered in the differential diagnosis of mass-like lung lesions in highly immunocompromised patients. This abstract is funded by: None
Cordero et al. (Fri,) studied this question.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: