Aggressive Progression of High Programmed Death-Ligand 1 (PD-L1) Non-small Cell Lung Cancer Presenting as Life-Threatening Esophageal Obstruction: A Case of Food Impaction Secondary to Subcarinal Lymph Node Compression.

Dysphagia secondary to esophageal obstruction is a rare but clinically relevant presentation in the setting of non-small cell lung cancer (NSCLC). While pembrolizumab demonstrates efficacy in metastatic NSCLC with high programmed death-ligand 1 (PD-L1), diagnostic challenges in distinguishing pseudoprogression from true progression and paradoxical disease progression pose a clinical challenge, highlighting complexities inherent in immune checkpoint inhibitor resistance mechanisms. We present the case of an 82-year-old Caucasian woman with a diagnosis of stage IV NSCLC with extremely high PD-L1 expression who developed accelerated disease progression on pembrolizumab monotherapy. Following 11 cycles of immunotherapy, the patient developed life-threatening esophageal obstruction due to a massively enlarged subcarinal lymph node, causing significant extrinsic compression. This resulted in food impaction necessitating urgent endoscopic management, followed by aspiration pneumonia requiring medical intensive care unit admission. Endoscopic evaluation revealed a critically narrowed esophageal lumen with ulcerated and necrotic mucosa. To facilitate nutritional support and airway protection, a gastrostomy tube was inserted. This case highlights several key clinical points: mediastinal lymphadenopathy can result in life-threatening esophageal compression requiring immediate intervention; high PD-L1 expression level is no guarantee of immunotherapy efficacy and may paradoxically be associated with aggressive disease progression; tissue sampling is imperative to differentiate between true progression versus pseudoprogression; and gastrostomy tube insertion is a vital palliative intervention for malignant esophageal obstruction secondary to extrinsic compression.