Bronchoscopic photodynamic therapy for endobronchial metastatic papillary thyroid carcinoma causing lobar airway obstruction: a case report.

Background: Bronchoscopic photodynamic therapy (PDT) is a guideline-supported, non-thermal modality for malignant central airway obstruction. It may be particularly advantageous for hypervascular endobronchial tumors in which immediate mechanical or thermal debulking carries heightened hemorrhage risk. While PDT is well described in primary lung malignancies, published experience in non-lung-primary endobronchial metastases remains limited. Case Description: A 71-year-old never-smoking woman with advanced radioactive iodine (RAI)-refractory BRAF V600E-mutated papillary thyroid carcinoma (PTC) with pulmonary, brain, and bone metastases presented with imaging evidence of a left lower lobe (LLL) lesion with endobronchial extension. Bronchoscopy demonstrated a friable, highly vascular endobronchial tumor causing approximately 90% obstruction of the LLL bronchus and a smaller non-occlusive lesion in the superior segment of the right lower lobe (RLL). Given lesion vascularity and bleeding-risk concerns with immediate debulking, a staged PDT approach was selected. Porfimer sodium [Photofrin; 2 mg/kg intravenous (IV)] was administered, followed by bronchoscopic light activation (630 nm) using a 2-cm cylindrical diffuser fiber. PDT was delivered to both lesions (100 J over 250 seconds per site). A repeat bronchoscopy 72 hours later demonstrated approximately 50% airway lumen improvement following removal of necrotic tissue and mucus, and PDT was repeated with identical parameters. Subsequent re-evaluation demonstrated necrotic post-PDT changes, and adjunctive cryodebulking was performed. Pathology confirmed metastatic PTC. Follow-up chest computed tomography demonstrated recanalization of the LLL bronchus and mild decrease in the dominant LLL mass. Conclusions: Staged bronchoscopic PDT and adjunct cryotherapy provided effective local airway control for hypervascular endobronchial metastatic PTC causing lobar obstruction, with complete response of a smaller non-obstructive RLL lesion, without major bleeding or airway compromise. PDT may be a safe and effective adjunctive therapy for selected patients with metastatic endobronchial PTC.