Rapid diagnosis of disseminated <i>Mycobacterium avium</i> complex infection mimicking metastatic malignancy using metagenomic next-generation sequencing

Disseminated non-tuberculous mycobacteria (NTM) disease, which is mainly found in immunocompromised individuals, is a rare and severe infection whose diagnosis poses a challenge to clinicians. We present a patient with disseminated NTM infection mistaken for metastatic malignancy in an otherwise healthy patient and the tortuous diagnostic process. Metagenomic next-generation sequencing (mNGS) played a critical role in the diagnosis. Further screening for anti-interferon-γ antibodies revealed that the patient had a potential immunodeficiency.