A Case of Anti-vascular Endothelial Growth Factor Therapy-Related Nephrotic Syndrome With Marked Intraglomerular Macrophage Infiltration

A 75-year-old woman with colon cancer and distant metastases was treated with fluorouracil, levofolinate, and irinotecan (FOLFIRI) plus bevacizumab postoperatively. During the 32nd course, the patient developed massive proteinuria, and only bevacizumab was discontinued; the proteinuria improved rapidly over time. However, more than six months later, the patient developed massive proteinuria again, and her renal function declined. Renal biopsy revealed glomerular microangiopathy with prominent foam cell infiltration into the glomerulus, which was thought to be caused by chronic endothelial cell damage to the glomerular capillaries. Endothelial cell damage is thought to be caused not only by the inhibition of vascular endothelial growth factor action of bevacizumab in the glomerular capillary but also by the cytotoxicity of the concomitant anticancer drugs and coexisting clinical conditions such as dyslipidemia and hypertension. After discontinuing anticancer agents and intensifying diet and antihypertensive therapy, proteinuria and dyslipidemia slowly improved; however, it became difficult to continue adequate chemotherapy, and the tumor marker levels worsened. Combination therapies, including molecular targeted agents, have become common, and the side effects of anticancer agents are expected to continue to be complicated. To prevent the onset and severity of renal complications, management of blood pressure, lipid level, and glucose metabolism, as well as multidisciplinary medical management, including dietary therapy, is required.