Focal Segmental Glomerulosclerosis Associated with Essential Thrombocythemia

A 72-year-old man was admitted for examination of proteinuria (9.14 g/day) and leg edema. Essential thrombocythemia (ET) was diagnosed because of thrombocytosis (platelet count, 57.9x104/& mu;L), elevated megakaryocytes in bone marrow biopsy, and JAK2 V617 mutation. Kidney biopsy led to a diagnosis of focal segmental glomerulosclerosis (FSGS) cellular variant (characterized by glomerular capillaries filled with swollen endothelial cells containing foam cells) in 6 glomeruli, FSGS tip variant in 5 glomeruli, and additional FSGS variants in other glomeruli. Affected glomeruli had anti-CD61 antibody staining-positive megakaryocyte infiltrations. ET may induce FSGS because megakaryocyte infiltration increases intraglomerular pressure, resulting in hypertension and proteinuria.

Automated summary

A 72-year-old man with proteinuria and leg edema was diagnosed with essential thrombocythemia (ET), identified by thrombocytosis, elevated megakaryocytes, and JAK2 V617 mutation. Kidney biopsy revealed focal segmental glomerulosclerosis (FSGS) cellular variant and other FSGS variants, with positive megakaryocyte infiltrations. ET may cause FSGS by increasing intraglomerular pressure due to megakaryocyte infiltration.