Polycythemia secondary to bilaterally enlarged kidneys in T-Cell acute lymphoblastic leukemia: a case report and literature review

Polycythemia is a rare disease that can cause hypertension. Secondary polycythemia with increased production of erythropoietin (EPO) is associated with several kidney diseases, including hydronephrosis and cystic disease. However, there have been no reports of a case presenting with polycythemia secondary to bilateral nephromegaly caused by renal infiltration of T-cell acute lymphoblastic leukemia (T-ALL). A 32-year-old Japanese man presented with marked hypertension (215/150 mmHg) with renal insufficiency (creatinine 3.7 mg/dL), proteinuria, hematuria, bilateral nephromegaly, polycythemia (hemoglobin 20.2 g/dL), and increased serum EPO (38.7 mIU/mL, range 4.2-23.7 mIU/mL). Based on renal and bone marrow biopsy findings, he was diagnosed with T-ALL and bilaterally enlarged kidneys caused by renal infiltration of leukemic cells. There was no evidence of endocrine hypertension or fluid retention. Remission induction chemotherapy led to a decrease in kidney size, hemoglobin levels, and serum EPO levels, and allowed dose reductions of most hypertensive drugs, suggesting that hypertension was secondary to polycythemia. The patient's renal function gradually improved and hemodialysis was discontinued after 1 month of chemotherapy. We report a case of marked hypertension and secondary polycythemia induced by severe renal infiltration of T-ALL at diagnosis, which were synchronically improved with induction chemotherapy. This case history suggests the importance of considering lymphoproliferative diseases in the differential diagnosis of secondary polycythemia, leading to severe hypertension.