Focal Segmental Glomerulosclerosis Associated with Essential Thrombocythemia

Area of Science:

• Nephrology
• Hematology
• Pathology

Background:

• Essential thrombocythemia (ET) is a myeloproliferative neoplasm characterized by elevated platelet counts.
• Focal segmental glomerulosclerosis (FSGS) is a significant cause of kidney disease and proteinuria.

Observation:

• A 72-year-old male presented with significant proteinuria (9.14 g/day) and leg edema.
• Diagnosis of ET was confirmed by thrombocytosis, bone marrow biopsy findings, and JAK2 V617 mutation.
• Kidney biopsy revealed various forms of FSGS, including cellular and tip variants.

Findings:

• Glomeruli affected by FSGS showed infiltration by megakaryocytes, identified by anti-CD61 antibody staining.
• The cellular variant of FSGS was characterized by swollen endothelial cells containing foam cells within glomerular capillaries.
• A correlation was observed between ET and the development of FSGS in the affected patient.

Implications:

• Megakaryocyte infiltration in glomeruli may increase intraglomerular pressure, contributing to hypertension and proteinuria.
• This case highlights a potential mechanism by which hematological disorders like ET can directly impact renal function.
• Understanding this link may inform diagnostic approaches and therapeutic strategies for patients with co-existing ET and kidney disease.