Leukemic Infiltrate of Renal Cortex Presenting as Reversible Kidney Injury Nivin Haroon, MD and Erdal Sarac, MD St. Elizabeth Health Center, Youngstown, Ohio INTRODUCTION We describe a case of CLL renal involvement whose onset was heralded by rising creatinine levels and worsening renal failure. CASE A 53-year-old male presented to the emergency room with chief complaint of epigastric pain. Review of systems was positive for an episode of epistaxis, sore throat, and recent weight loss. Past medical history included hypertension, dyslipidemia, and diabetes mellitus with nephropathy. Laboratory analysis revealed elevated amylase, lipase and triglycerides, as well as thrombocytopenia, neutropenia and relative lymphocytosis. Abdominal CT scan showed splenomegaly. Examination of bone marrow aspirate showed non-Hodgkin’s lymphoproliferative disorder and tissue change consistent with chronic lymphocytic leukemia (CLL). Comparatively rapid worsening of base line kidney function was observed: baseline creatinine level of 1.5 increased to 3.4 within a few weeks. Given the CLL diagnosis, renal biopsy to exclude involvement was undertaken. Pathological examination of the kidney illustrated dense cortical interstitial infiltrate, similar to that observed on bone marrow aspirate examination. Immune complex disorders were ruled out with electron and fluorescent microscopy. Because of rising creatinine levels weeks prior to onset of other clinical signs and symptoms, worsening renal function was viewed as the harbinger of CLL. With chemotherapy for CLL, kidney function demonstrated significant improvement. Creatinine levels returned to baseline with chemotherapeutics. CREATININE TREND & PATHOLOGY SPECIMENS DISCUSSION CLL renal involvement with resulting kidney failure has been reported only in a handful of cases. In our scenario, diffuse infiltrate might have led to tubule and microvasculature compression resulting in renal failure. Other postulated mechanisms of kidney failure in CLL include vasculitis, paraneoplastic syndrome, glomerulonephritis, and extrinsic compression from splenomegaly. Vigilance for unusual CLL presentations should be maintained in the diagnostic differential armortorium. REFERENCES Da'as N, et al Kidney involvement and renal manifestations in non-Hodgkin's lymphoma and lymphocytic leukemia: a retrospective study in 700 patients.Eur J Haematol. 2001 Sep;67(3):158-64. Hewamana S, Pepper C, Jenkins C, Rowntree C. Acute renal failure as the presenting feature of leukaemic infiltration in chronic lymphocytic leukaemia. Clin Exp Nephrol 2009; 13:179–181. Aslam N, et al Nephrotic syndrome in chronic lymphocytic leukemia: a paraneoplastic syndrome? Clin Nephrol. 2000 Dec;54(6):492-7. Quenneville LA, Magil AB. Renal failure due to T-cell mediated lymphocytic vasculitis: an unusual complication of B-cell chronic lymphocytic leukemia.Am J Kidney Dis. 2000 Sep;36(3):E17. Schwartz JB, Samsuddin AM. The effects of leukemic infiltrates in various organs in chronic lymphocytic leukemia. Hum Pathol. 1981; 12:432–440 Tucker B, Brown A, D’Ardenne J, Cattell W. Reversible renal failure due to renal infiltration and associated tubulointerstitial disease in chronic lymphocytic leukemia. Nephrol Dial Transplant. 1990; 5:616–618. Pagniez D, et al A. Reversible renal failure due to specific infiltration in chronic lymphocytic leukemia. Am J Med. 1988; 85:570–580. Figure 1:Creatinine trend before and after treatment for CLL with chemotherapy. Figure 2: Bone marrow smear with small lymphocytes predominating (400X) Figure 3: Renal cortex with small lymphocyte infiltration (200X) Figure 4: Renal cortex with small lymphocyte infiltration within the interstitium (400X) To rule out other glomerular pathology fluorescent microscopy examination was also done which came back negative for any significant finding.