Clinical and Pathological Features of Renal Presentations in Polycythemia Vera

Background: Polycythemia vera (PV) is a common type of Philadelphia chromosome-negative chronic myeloproliferative disorder. PV-associated kidney disease is rarely reported and remains poorly understood. It has been observed that chronic kidney disease could be a risk factor for poor prognosis in PV.

Methods: We retrospectively analyzed the clinicopathological features of renal presentations in eight patients with confirmed PV-associated kidney disease.

Results: The eight patients were 6 males and 2 females, with a mean age of 46.4 ± 16.8 years. Six patients had a history of PV, with a duration range 0.5-16 years. The other two patients were newly diagnosed with PV simultaneously with glomerular disease. Seven patients conducted a JAK2 V617F mutation test, with a positive result in five. Proteinuria and renal dysfunction were the patients' main complaints, with only one having nephrotic syndrome and three having microscopic hematuria. The level of proteinuria ranged from 0.52-10.96 g/day. Three patients had advanced chronic kidney disease (CKD), two in stage 3b and one in stage 4, but only one patient had anemia. Three patients had monoclonal immunoglobulinemia, one patient with immunoglobulin (Ig) G kappa plus light chain lambda, one patient with IgG kappa, and one patient with IgG lambda. Five patients underwent a renal biopsy. The pathological diagnosis was IgA nephropathy in three, non-IgA mesangial proliferative glomerulopathy in one, and glomerular hypertrophy with ischemic renal injury in one patient. Glomerular ischemia, ischemic shrinkage, focal segmental sclerosis, and glomerulomegaly were common pathological features. Glomerular crescents and endocapillary proliferation were also observed. All patients were administered hydroxyurea, and seven were administered renin-angiotensin system inhibitors. During follow-up, one patient with uncontrolled PV developed secondary myelofibrosis and died, three patients were lost to follow-up, and four patients remained alive with CKD.

Conclusions: Patients with untreated or uncontrolled PV could have massive proteinuria and advanced CKD, pathologically showing ischemic, sclerosing glomerular lesions with hypercellurity, glomerular crescents and endocapillary proliferation. IgA nephropathy was most commonly diagnosed. These findings deserve attention because early screening and effective control of PV may benefit the long-term kidney prognosis.