RESUMEN
Acute lymphoid leukemia is the most frequently occurring malignancy in childhood, but acute tubulointerstitial nephritis with associated acute renal failure as the leading manifestation of leukemia is extremely rare. Only a few pediatric cases have been described in the literature. We present a surprising case in which physical examination and initial investigation were not typical for leukemia. Ultrasound showed only modest kidney enlargement while laboratory results indicated acute renal failure. Renal biopsy indicated tubulointerstitial nephritis, and subsequent steroid treatment led to sudden clinical improvement. One month later, however, the patient returned with typical clinical features of leukemia. Re-evaluation of the original kidney biopsy block indicated T-cell acute lymphoid leukemia. The present case highlights the importance of renal biopsy.
