Isolated Renal Chronic Graft-versus-Host Disease Presenting as Thrombotic Microangiopathy after Hematopoietic Stem Cell Transplantation: A Diagnostic Challenge

Hematopoietic stem cell transplantation (HSCT) is a curative modality for various hematological malignancies. Renal complications are increasingly recognized after transplant, with chronic kidney disease (CKD) developing in 15%–20% of patients. Transplant-associated thrombotic microangiopathy (TMA) is a potential but often underdiagnosed etiology. We report a case of CKD with biopsy-proven chronic TMA following allogeneic HSCT, most likely secondary to chronic graft-versus-host disease (GVHD), in the absence of systemic GVHD or other typical TMA triggers. Although electron microscopy was not performed, histological features supported chronic TMA. Immunosuppression with corticosteroids led to stabilization of renal function. This case emphasizes the need to consider renal-limited GVHD in the differential diagnosis of post-HSCT renal dysfunction, even when extrarenal manifestations are absent.