Renal involvement by chronic myelomonocytic leukemia requiring nephroureterectomy.

Chronic monomyelocytic leukemia (CMML) is a relatively rare clonal hematologic disorder with features of myelodysplastic syndrome and myeloproliferative disease. Renal impairment from CMML is infrequent and can result from both direct (ie, infiltrative) and indirect (eg, vasculitis, infarction) mechanisms. This case report describes a patient with refractory gross hematuria requiring nephroureterectomy with diffuse involvement of the upper tract by CMML and accompanying extramedullary hematopoiesis. Underscored are the need to maintain a broad differential diagnosis for upper tract lesions in the setting of gross hematuria, and the potential need for drastic measures to control upper tract bleeding if conservative measures fail.