Etiologies and Diagnostic Yield of Bone Marrow Evaluation in Adults Living with HIV in Venezuela: A Cross-Sectional Study

Background: Bone marrow abnormalities in people living with HIV may reflect infectious, neoplastic, or inflammatory processes, particularly in advanced disease presenting with fever of unknown origin or unexplained cytopenias. In Latin America, contemporary data on the causes and diagnostic contribution of bone marrow evaluation remain limited, especially in resource-constrained settings. Aim: To characterize the etiologies, histopathological patterns, and diagnostic contribution of bone marrow evaluation in adults living with HIV at a tertiary referral center in Venezuela. Methods: We conducted a cross-sectional study with retrospective and prospective case ascertainment among adults with confirmed HIV infection who underwent bone marrow aspiration, biopsy, or both for suspected infiltrative disease between January 2019 and April 2024. We analyzed clinical, laboratory, histopathological, microbiological, and molecular data at the index bone marrow evaluation. Test-specific denominators are reported because diagnostic investigations were not uniformly available. Results: Forty-two patients were included (35 retrospectively and 7 prospectively); 59.5% were male and the median age was 39 years (IQR: 31.75–50.0). At presentation, 67% were newly diagnosed with HIV and 79% were ART-naive; the median CD4+ T-cell count was 98.5 cells/mm3. Histopathology was evaluable in 37/42 patients; 31/37 (83.8%) showed findings compatible with infectious involvement and 6/37 (16.2%) showed malignancy. Histoplasma capsulatum was isolated in 17/35 fungal cultures (48.6%), Mycobacterium tuberculosis in 13/33 mycobacterial cultures (39.4%), and CMV PCR on bone marrow aspirate was positive in 2/3 patients tested. The final etiologic classification was infectious in 36/42 patients (85.7%) and neoplastic in 6/42 (14.3%). Conclusions: In this highly selected cohort of adults with advanced HIV disease, infectious etiologies-particularly histoplasmosis and tuberculosis-predominated. Bone marrow aspiration and biopsy, interpreted together with microbiological and molecular testing, provided clinically relevant diagnostic information in patients with prolonged fever, cytopenias, or otherwise inconclusive investigations. The findings support earlier HIV diagnosis and ART initiation and improved access to fungal, mycobacterial, and molecular diagnostics in resource-limited settings.