Acute Kidney Failure and Nephromegaly as Initial Presentation of Recurrent Hematologic Malignancy

Introduction: Acute Lymphoblastic Leukemia (ALL) is most commonly diagnosed and monitored for recurrence based on laboratory findings such as leukopenia, anemia, and thrombocytopenia. It rarely presents as acute kidney injury (AKI) due to infiltration of leukemia cells into kidney tissue. Only a few cases have been reported in the literature thus far. Case Description: We present a case of a 27 year old male with a history of Philadelphia negative B Cell ALL who achieved remission after chemotherapy and matched unrelated peripheral stem cell transplant in 2022 who then presents to the hospital with fatigue one year after remission. His fatigue was initially attributed to recently diagnosed atrial flutter that persisted despite outpatient medical management. Labs on admission revealed white blood cell count 4 X 10 3/uL, hemoglobin 9 g/dL, platelet count 200 x103/uL, creatinine 6.9 mg/dL, blood urea nitrogen 98 mg/dL, bicarbonate 9 mEq/L, and with an anion gap of 15. Renal ultrasound showed enlarged bilateral kidneys measuring at 18 cm for the right kidney and 19.5 cm for the left kidney with diffuse abnormal renal cortical parenchymal texture. Due to concern for infiltrative disease, he underwent a kidney biopsy. His biopsy revealed renal cortical tissue diffusely infiltrated by a densely cellular neoplasm composed by atypical lymphoid cells. Patient was started on chemotherapy and eventually underwent Chimeric Antigen Receptor T- cell therapy to treat his ALL recurrence. With treatment, his kidney function improved and has remained stable at a new baseline of Creatinine of 2 mg/dL. Our case highlights AKI and nephromegaly as a sign of recurrent ALL. Discussion: Renal dysfunction is an uncommon presentation of recurrent ALL especially in absence of leukopenia, anemia, and thrombocytopenia. Nephromegaly can be caused by several diseases such as diabetes mellitus, HIV associated nephropathy, interstitial nephritis, and infiltrative diseases such as hematologic malignancies and amyloid. Renal biopsy was crucial in diagnosing the cause of our patient’s AKI as well as his recurrent malignancy as he did not have hematologic signs of recurrence. This case report highlights the importance of renal biopsy in patients who present with nephromegaly, especially in patients with known cancer history.