Classic biphasic pulmonary blastoma with endobronchial invasion in a 16-year-old male: A rare case report.

Pulmonary blastoma (PB) is a rare and aggressive lung neoplasm, representing 0.25 %-0.50 % of lung cancers and characterized by biphasic histology with both epithelial and mesenchymal components. We report a case of a 16-year-old male non-smoker presenting with hemoptysis and a 2-month history of dry cough and exertional dyspnea. Imaging revealed an ill-defined density in the left lung, and bronchoscopy identified a budding mass in the left bronchus. Biopsy results showed malignant spindle cells, with immunohistochemical staining positive for cytokeratin, vimentin, and TTF1, confirming classic biphasic pulmonary blastoma (CBPB). Further CT scans indicated multiple metastases in the right lung and bones. The patient was referred for palliative chemotherapy due to the tumor's aggressive nature. This case highlights the clinical presentation and diagnostic challenges of PB with endobronchial invasion.