T-cell lymphoblastic lymphoma presenting with type B lactic acidosis and acute kidney injury in an adolescent.

Acute kidney injury (AKI) in children is a major cause of morbidity and mortality and is most commonly associated with dehydration, sepsis, or nephrotoxic exposures. In rare instances, however, hematologic malignancies may lead to AKI through direct renal infiltration. We report on a 13-year-old boy who presented with AKI, refractory metabolic acidosis, and severe hyperlactatemia in the absence of sepsis or hypoperfusion. Imaging studies revealed bilateral nephromegaly with heterogeneous renal parenchyma. Kidney biopsy demonstrated diffuse infiltration of the kidneys by T-cell lymphoblastic lymphoma. The metabolic findings were consistent with type B lactic acidosis, likely driven by the Warburg effect. Following initiation of chemotherapy, lactate levels rapidly normalized. This case highlights the importance of considering underlying hematologic malignancy in children presenting with AKI accompanied by unexplained lactic acidosis and nephromegaly. Early recognition, prompt kidney biopsy, and timely oncologic treatment are essential for accurate diagnosis and improved outcomes.