Abstract
BACKGROUND: Essential thrombocythemia (ET) is a myeloproliferative neoplasm characterized by the uncontrolled proliferation of megakaryocytes and sustained thrombocytosis. Although its impact on renal function is not well established, a few case reports have described glomerular involvement and associated kidney impairment. CASE REPORT: We present the case of a 79-year-old man with ET and stage 3b/A2 chronic kidney disease (CKD), who was admitted with severe acute kidney injury (AKI). This episode was associated with a progressive rise in platelet count, reaching 1,350,000/μL after discontinuation of anagrelide and loop diuretics. Renal biopsy (RB) revealed structural lesions compatible with a myeloproliferative neoplasm, including acute tubular necrosis (ATN), glomerulomegaly, and thrombotic microangiopathy (TMA). Cytoreductive therapy with hydroxyurea and corticosteroids was initiated, resulting in improvement of renal function and achievement of complete hematologic remission. DISCUSSION: During follow-up, a linear correlation was observed between increasing platelet counts and declining renal function, underscoring the need for dynamic therapeutic adjustment and close monitoring to prevent progression to end-stage renal disease (ESRD). CONCLUSIONS: This case highlights the importance of nephrological evaluation in patients with ET and supports the role of cytoreductive therapy in managing ET-associated renal complications.