Successful treatment of eosinophilia associated with dialysis‐related renal cancer with radical nephrectomy

Introduction Secondary eosinophilia due to solid tumors is a rare case. This is the first study to report secondary eosinophilia due to renal cancer in a patient on dialysis. Case presentation A 70‐year‐old man, on long‐term hemodialysis was incidentally detected with right renal cancer, and workup performed revealed eosinophilia. Allergic symptoms caused by hemodialysis were initially considered; however, treatment did not lead to any improvement in eosinophilia. Therefore, nephrectomy for renal cancer was performed. The resolution of symptoms and eosinophilia after surgery suggested renal cancer as the cause of eosinophilia. Conclusion As demonstrated in this patient with dialysis‐related renal cancer, eosinophilia associated with solid tumors may be addressed by treating the tumor.