Nucleated Red Blood Cells in Circulation

The patient is a 70-year-old male who presents with a creatinine of 5 mg/dl and a history of primary myelofibrosis. The biopsy shows a kidney with severe glomerular and tubulointerstitial chronicity, approaching end-stage kidney disease from arterionephrosclerosis. Interestingly, circulating nucleated red blood cells were identified in the arteries and peritubular capillaries. Although not representing a specific kidney disease, the presence of nucleated red blood cells within the circulation points toward premature release of erythroid precursors from the bone marrow. This finding is has been reported in the setting of a space-occupying lesion in the bone marrow from metastases or in myeloproliferative disorders.