Abstract
A 68-year-old male with gastric cancer was treated with tegafur/gimeracil/oteracil and oxaliplatin for 6 months. Thereafter, he was treated with paclitaxel and ramucirumab for 3 months. However, neither regimen had much effect. Thus, he was treated with nivolumab for 2 months, but he developed proteinuria, microhematuria, and an acute kidney injury. A kidney biopsy revealed occasional swollen endothelial cells and proliferating mesangial cells. Few abnormal findings were seen in the tubules or interstitial tissue. Immunofluorescent staining showed segmental immunoglobulin A and complement component 3 deposition, in the mesangial area. Electron microscopy showed a small amount of electron-dense deposits in the paramesangial area and swollen endothelial cells. Mesangial interposition, the loss of endothelial cell fenestration, and subendothelial edema were also observed. Furthermore, foot process effacement and villous transformation of epithelial cells were noted. After the discontinuation of nivolumab, the patient's renal function gradually improved, and his proteinuria disappeared. Nivolumab treatment was restarted at that time because of cancer progression; however, it was ineffective. No occult blood was detected from 7 months after the administration of the last dose of nivolumab. This is a unique case, in which a kidney biopsy revealed evidence of nivolumab-associated glomerular endothelial injury.