RESUMO
Acute renal failure secondary to lymphomatous infiltration of the kidneys is a rare manifestation raer mantle cell lymphoma (MCL). We present the case of a 76-year-old gentleman with acute renal failure an a background of previously treated low grade non-hodgkin lymphoma. At the time of presentation he complained only of mild lethargy und had no lymphadenopathy or organomegaly. Renal ultrasound revealed bilaterally enlarged kidneys and renal biopsy confirmed MCL. Mantle cell lymphoma runs an aggressive course and accurate diagnosis is very important in guiding appropriate treatment. This case demonstrates the importance of renal biopsy in the diagnosis of renal lymphomatous infiltration but also highlights the potential utility of histological examination in guiding targeted therapy.