Disseminated nocardiosis is an uncommon but often underrecognized cause of granulomatous, miliary-type disease that can closely mimic tuberculosis (TB) radiologically and histopathologically. This report describes a postpartum woman with chronic, non-resolving pneumonia, miliary pulmonary and renal nodularities, and a central nervous system (CNS) lesion who was repeatedly managed as disseminated TB despite extensive negative mycobacterial investigations and lack of clinical improvement. Shotgun metagenomic next-generation sequencing (mNGS) of bronchoalveolar lavage (BAL) fluid ultimately detected Nocardia transvalensis, supporting a diagnosis of disseminated nocardiosis, and the patient responded to targeted therapy. No Nocardia sp. isolate was recovered in culture; species-level identification was therefore based on mNGS interpreted in its clinical context. This difficult-to-diagnose case highlights the diagnostic value of mNGS for culture-negative disseminated infections, the importance of critically interpreting sequencing results, and the need to consider nocardiosis when TB remains unconfirmed.
