Incidental early diagnosis of biphasic pulmonary blastoma in a patient with history of stage IV lung adenocarcinoma

Biphasic pulmonary blastoma is a rare but lethal type of lung malignancy with characteristic histology of both epithelial and mesenchymal components. Previously reported cases have been limited to presentation at advanced stages, suggesting that the clinical course of the disease is usually aggressive. Here, we report a case of incidental diagnosis of biphasic pulmonary blastoma by imaging surveillance in a patient previously treated for adenocarcinoma of the lung. The patient was diagnosed with stage 1 disease and underwent successful resection. Next‐generation sequencing (NGS) revealed a high mutation burden, a finding not previously reported in a patient with biphasic pulmonary blastoma.