Metagenomic next-generation sequencing unveils invasive aspergillosis masquerading as miliary tuberculosis in a neutropenic leukemia patient: a case report.

Background: Empirical anti-tuberculosis therapy is a common strategy when patients with acute leukemia chemotherapy-induced neutropenia develop diffuse pulmonary small nodular and subsolid lesions. However, the absence of pathogenetic verification may lead to catastrophic consequences. Methods: Following negative conventional microbiological cultures (bronchoalveolar lavage bacterial culture, Gram/Gram-negative test) and ineffective anti-infective therapy, a second bronchoscopy revealed caseous obstructive lesions in the right upper lobe bronchus. Metagenomic Next-Generation Sequencing (mNGS) analysis of lavage fluid ultimately confirmed invasive pulmonary fungal disease. Results: The mNGS analysis of the bronchoalveolar lavage fluid (BALF) reported 6,750 Conclusion: This case demonstrates that invasive pulmonary fungal infection can perfectly mimic the typical radiographic features of hematogenous disseminated pulmonary tuberculosis, including diffuse small nodular and subsolid lesions with a miliary distribution pattern predominantly in the upper lobes and extrapulmonary manifestations such as erythema nodosum. For unexplained pulmonary infections in immunocompromised hosts where conventional diagnosis and empirical treatment fail, the timely application of bronchoscopy combined with mNGS technology represents a critical breakthrough for achieving precise diagnosis.