Bronchial Chondronecrosis After Proton Beam Therapy Successfully Treated With Hyperbaric Oxygen Therapy

Airway chondronecrosis is a rare but serious manifestation of late radiation-induced toxicity. We report the case of a 67-year-old woman with epidermal growth factor receptor mutation-positive lung adenocarcinoma who developed bronchial chondronecrosis 8 years after proton-beam therapy (PBT) to the right upper lobe nodule. For 2 years, she was treated for cough-variant asthma owing to a persistent cough. Chest computed tomography (CT) showed only a subtle irregularity of the right main bronchial wall. Bronchoscopy revealed yellow necrotic deposits in the right main bronchi. Although a conventional forceps biopsy was nondiagnostic, transbronchial lung cryobiopsy (TBLC) obtained cartilage specimens, confirming bronchial chondronecrosis without malignancy. Hyperbaric oxygen therapy (HBOT) (90 sessions in total) led to symptomatic and bronchoscopic improvement. This case highlights that very-late-onset airway chondronecrosis following PBT must be considered, even with minimal CT findings. TBLC is a valuable tool for diagnosing submucosal lesions and HBOT appears to be an effective therapy.