Two Cases Presenting with Acute Renal Failure: One with Renal Lymphoma and Other with Lung Cancer Metastases to the Kidneys

Acute renal failure (ARF) due to tumor cell infiltration to the renal parenchyma is a rare condition. Here, we report two cases; first one with lung carcinoma metastasis to renal parenchyma and the second one with non-Hodgkin lymphoma infiltration of renal parenchyma both presenting with acute renal failure and diagnosed by renal biopsy. Case 1: A 66-year-old female patient was admitted with dyspnea, pretibial edema and oliguria (200 cc/day). On physical examination a blood pressure of 160/110 mmHg, bilateral pretibial edema and hepatomegaly palpable 5 cm below the costal margin were noticed. Laboratory test results were significant for a Blood Urea Nitrogen (BUN) level of 141 mg/dL, serum creatinine level of 5.9 mg/dL, LDH level of 2562 IU/L, anemia, leukocytosis (WBC:20.000/µL), 2(+) proteinuria, microscopic hematuria and pyuria. Intractable metabolic acidosis developed despite conservative treatment and hemodialysis was therefore initiated. Bilateral enlargement of the kidneys was noted in urinary system ultrasonography (USG). Percutaneous kidney biopsy was performed and pathologic examination of biopsy specimens was significant for diffuse malignant lymphoid infiltration of the renal tubulointerstitium. Immunohistochemical examination (IHE) revealed CD20, CD10 and MUM1 positive neoplastic cells. High grade diffuse large B cell lymphoma was diagnosed. Case 2: A 65-yearold male patient was diagnosed with squamous cell lung carcinoma and underwent left pneumonectomy in April 2009. At that time, his serum creatinine level was 1.2/mg/dl. Macroscopic hematuria and 0.5g/ day proteinuria was detected 11 months after the diagnosis. On physical examination pallor, absence of breath sounds on left hemithorax and hepatomegaly palpable 2 cm below the right costal margin were noticed. His laboratory tests were significant for anemia, a BUN level of 85 mg/dl and serum creatinin level of 4.2 mg/dl. The sizes of both kidneys and their parenchymal thicknesses were within normal limits on urinary USG. Pathology examination of percutaneous kidney biopsy specimens demonstrated malignant cell infiltration of the renal tubulointersititium. IHE of the specimens were negative for cytokeratin-20 and thyroid transcription factor-1 (TTF-1) but were positive for P63. A diagnosis of squamous cell carcinoma metastasis to kidneys was made. Conclusion: Tumor cell infiltration of kidneys from a distant source is a rare cause of ARF. Kidney biopsy should be performed to reveal the underlying etiology of ARF in cases where there is a high degree of suspicion, .