Renal Pelvic Cancer with Multiple Lung Metastases in a Patient with Polycystic Kidney Disease, Initially Diagnosed as Non-small Cell Lung Cancer: An Autopsy Case Report

A 64-year-old man with autosomal dominant polycystic kidney disease (ADPKD) on hemodialysis presented with multiple lung masses. A computed tomography (CT)-guided biopsy revealed non-small cell lung cancer (NSCLC). A cavitary mass in the right lung indicated primary NSCLC (cT2N1M1a, stage IVA). Pembrolizumab was initiated because of a high programmed death-ligand 1 (PD-L1) expression (90%). On day 10 post-treatment, he developed acute respiratory failure with diffuse ground-glass opacities on chest CT, indicative of pembrolizumab-induced lung injury. Despite steroid pulse therapy, the patient died on day 13. An autopsy revealed left renal pelvic cancer with lung metastases, highlighting the diagnostic challenges in ADPKD.