Diagnosis of lung squamous cell carcinoma based on metagenomic Next-Generation Sequencing.

Background: The clinical treatment of patients suspected of pulmonary infections often rely on empirical antibiotics. However, preliminary diagnoses were based on clinical manifestations and conventional microbiological tests, which could later be proved wrong. In this case, we presented a patient whose initial diagnosis was lung abscess, but antibiotic treatments had no effect, and metagenomic Next-Generation Sequencing (mNGS) indicated presence of neoplasm.

Case Presentation: A 62-year-old female was diagnosed with lung abscess at three different health facilities. However, mNGS of bronchoalveolar lavage fluid did not support pulmonary infections. Rather, the copy number variation analysis using host DNA sequences suggested neoplasm. Using H&E staining and immunohistochemistry of lung biopsy, the patient was eventually diagnosed with lung squamous cell carcinoma.

Conclusions: mNGS not only detects pathogens and helps diagnose infectious diseases, but also has potential in detecting neoplasm via host chromosomal copy number analysis. This might be beneficial for febrile patients with unknown or complex etiology, especially when infectious diseases were initially suspected but empirical antibiotic regimen failed.