Paraneoplastic Minimal Change Disease Signaling Post-Transplant AML Relapse: Two Cases and a Literature Review.

Membranous nephropathy (MN) and minimal change disease (MCD) are the most common causes of nephrotic syndrome following hematopoietic stem cell transplantation (HSCT), a complication conventionally attributed to chronic graft-versus-host disease (GVHD). Paraneoplastic MCD is well described in lymphoid malignancies but is rarely reported in myeloid neoplasms. We report two cases of biopsy-confirmed MCD presenting as the initial manifestation of acute myeloid leukemia (AML) relapse following allogeneic HSCT. Both patients were White men in their sixties with relapsed/refractory AML who developed nephrotic-range proteinuria and acute kidney injury after matched unrelated donor HSCT without histologic evidence of GVHD. Renal biopsies confirmed MCD in both cases. Corticosteroid therapy was ineffective in halting renal deterioration; renal function improved only after initiation of leukemia-directed therapy, with one patient achieving dialysis independence. These cases highlight a rare paraneoplastic presentation of AML relapse. Nephrotic syndrome due to MCD may signal post-HSCT leukemia recurrence, and evaluation for AML relapse warrants consideration in steroid-refractory cases or those without concurrent GVHD. In such cases, control of the underlying malignancy, rather than escalation of immunosuppression, may be central to renal recovery.