Cavitary Pulmonary Metastases From Tongue Cancer Mimicking Pulmonary Tuberculosis: A Case Report

Cavitary lung lesions have a broad differential diagnosis, including infectious, inflammatory, and malignant diseases.A 33-year-old woman presented with hemoptysis and left-sided chest pain 20 months after curative resection of tongue squamous cell carcinoma.Chest computed tomography revealed multiple cavitary lesions in the left upper lobe with surrounding centrilobular nodules and left pleural effusion, raising concern for pulmonary tuberculosis.Three sputum smears for acid-fast bacilli, sputum polymerase chain reaction for Mycobacterium tuberculosis, and an interferon-gamma release assay were negative.Despite empirical antibiotic therapy, the pulmonary lesions showed no improvement.Bronchoscopy with transbronchial biopsy demonstrated squamous cell carcinoma morphologically similar to the previous tongue cancer, supporting the diagnosis of pulmonary metastases.Marked radiological improvement was observed after six cycles of pembrolizumab.This case highlights the diagnostic challenge of distinguishing cavitary pulmonary metastases from pulmonary tuberculosis, particularly when cavitary lesions are accompanied by centrilobular nodules, and underscores the importance of histopathological confirmation.