Case Report: A rare presentation of pulmonary tuberculosis with extensive ground-glass opacities in an immunocompetent patient: lessons from metagenomic next-generation sequencing

Pulmonary tuberculosis (PTB) is typically diagnosed through sputum smear microscopy and culture. However, diagnosis is challenging in patients with atypical radiological features and negative conventional tests. Ground-glass opacities (GGOs) are common but non-specific computed tomography (CT) findings and are rarely observed in immunocompetent PTB patients. We report the first case of an immunocompetent 53-year-old female presenting with extensive bilateral GGOs without classic clinical symptoms. Conventional microbiological cultures, acid-fast staining, and serological assays were all negative. Metagenomic next-generation sequencing (mNGS) of bronchoalveolar lavage fluid identified <i>Mycobacterium tuberculosis</i>, further supported by a positive T-spot TB assay. Standard anti-tuberculosis therapy led to complete resolution of GGOs over nine months, confirmed by follow-up CT imaging. This case underscores the diagnostic challenge of atypical PTB presenting with non-classical CT manifestations in an immunocompetent host. It highlights the decisive role of mNGS as a complementary tool in cases where conventional methods fail, enabling timely diagnosis, precise treatment, and improved patient outcomes.