A Rare Case Report of Postoperative Paraneoplastic Glomerulopathy in Kidney Transplant.

Kidney transplant recipients are more likely to develop posttransplant renal cell carcinoma than the general population. Symptoms of renal cell carcinoma are often nonspecific, such as nausea, vomiting, and weight loss, and tend to occur syndrome caused by the release of peptides and hormones by the cancer itself. However, there have been rare case reports of postoperative paraneoplastic glomerulopathy associated with renal cell carcinoma in kidney transplant recipients. Here, we report the case of a 54-year-old male who presented with subnephrotic range proteinuria with a urine protein-to-creatinine ratio of 1.0 within 1 year after a deceased donor kidney transplant without kidney function decline. The transplant team decided to perform a biopsy of the transplanted kidney, and the ultrasonography before intervention revealed a right- side native renal mass. The result of the kidney biopsy revealed focal segmental glomerulosclerosis. At the same time, computed tomography was done to find the cause of the renal mass, and we found that the right native kidney mass had features highly suspicious for renal cell carcinoma. The urologist subsequently performed a right radical nephrectomy. The pathology diagnosis of the kidney mass was renal cell carcinoma. After the cancer had been eliminated, clinical improvement of proteinuria was achieved. Hence, we diagnosed a rare secondary focal segmental glomerulosclerosis from renal cell carcinoma (paraneoplastic glomerulopathy) about which, to our knowledge, there are no previous reports. To date, there is no consensus recommendation for screening postoperative renal cell carcinoma in organ transplant recipients. The potential postoperative diagnosis of paraneoplastic glomerulopathy-associated renal cell carcinoma in kidney transplant recipients must be recognized.