Acute Methotrexate-Induced Crystal Nephropathy

Methotrexate-induced nephrotoxicity is not uncommon, although intrarenal methotrexate crystals have been elusive. This case shows methotrexate crystals deposited within the kidney tubules of a patient with methotrexate-induced nephropathy. To the Editor: Acute renal failure occurs in approximately 2% of patients who receive high-dose methotrexate for the treatment of a hematologic cancer. 1 – 3 Despite the frequency of acute renal failure and the occurrence of distinct urinary crystals in this context, 4 , 5 the presence of these crystals in human tissues has not been clearly documented. Here, we describe crystals within the kidney tubules of a patient with methotrexate-induced nephropathy. A 52-year-old man with an aggressive B-cell lymphoma was prescribed intravenous methotrexate (1.20 g per square meter of body-surface area over a 1-hour period, followed by 0.24 g per square meter . . .