A Case of Primary Endobronchial Hyalinizing Clear Cell Carcinoma Presenting as an Oncologic Emergency Due to Complete Left Main Bronchus Obstruction Successfully Managed with Airway Intervention.

A 66-year-old man presented with dyspnea and severe hypoxemia, requiring mechanical ventilation. Computed tomography revealed an obstruction of the left main bronchus by a bronchial tumor, thus prompting airway intervention to relieve the stenosis. A histopathological examination of the tumor revealed clear cytoplasm and hyalinized stroma, and rearrangement of EWSR1 was detected by a fluorescence in situ hybridization analysis. Comprehensive genomic profiling was performed because of the rarity of this case. GenMineTOP, capable of detecting the EWSR1::ATF1 fusion, contributed to a definitive diagnosis of hyalinizing clear cell carcinoma. Bronchoscopic airway intervention can serve as both a therapeutic and diagnostic procedure; GenMineTOP was useful in establishing a definitive diagnosis.