Precursor T-lymphoblastic lymphoma presenting as primary renal lymphoma with acute renal failure.

We report a case of acute renal failure (ARF) and bilateral nephromegaly in a patient with a history of Crohn's disease and treatment with azathioprine. Kidney biopsy revealed diffuse renal infiltration by precursor T-cell lymphoblastic lymphoma (T-LBL). At the time of diagnosis, no extrarenal manifestations of the lymphoma were detectable and therefore the lymphoma was categorized as primary renal lymphoma (PRL). Thus far, precursor T-LBL presenting as PRL has not been described before. We emphasize that in patients with ARF and bilateral renal enlargement, renal lymphoma is an important differential diagnostic consideration.