Acute lymphoid leukemia is the most common cancer in children, but cases presenting with acute tubulointerstitial nephritis and kidney failure are very rare.
In this case, the initial exams and ultrasound only suggested mild kidney issues, but lab results indicated acute renal failure, leading to a renal biopsy that revealed tubulointerstitial nephritis.
After steroid treatment improved the patient's condition, they later returned with signs of leukemia, confirming the original biopsy showed T-cell acute lymphoid leukemia, emphasizing the critical role of renal biopsy in diagnosis.