Disseminated tuberculosis secondary to polymicrobial co-infection following long-term immunotherapy for sarcomatoid mesothelioma: A case report.

Malignant pleural mesothelioma (MPM), particularly its sarcomatoid subtype, is a highly aggressive sarcoma of the pleural lining with a dismal prognosis. Prolonged use of immune checkpoint inhibitors (ICIs), while improving survival in selected patients, can induce profound immunosuppression, increasing susceptibility to life-threatening opportunistic infections. This report describes a 77-year-old male with sarcomatoid MPM who developed fatal disseminated tuberculosis (TB), accompanied by concurrent Aspergillus and herpesvirus infections during extended immunotherapy. The case underscores the critical role of metagenomic next-generation sequencing (mNGS) in enabling rapid diagnosis of atypical TB reactivation in an immunocompromised host, even when conventional cultures are negative. mNGS identified co-infections with Aspergillus flavus and herpesviruses (HHV-5, HHV-4, HHV-1), demonstrating its superiority in polymicrobial infection detection.