Primary renal lymphoma presenting with chronic low-grade fever.

Primary renal lymphoma (PRL) is a rare form of extranodal non-Hodgkin's lymphoma often diagnosed and treated by oncologists and urologists. Pathophysiological and clinical data on PRL are sparse, but the limited reported experience suggests the disease usually has an ominous outcome. As in other renal tumors, comprehensive radiological investigations have a central role in the recognition and final diagnosis of PRL. We describe the presenting features and clinical course of an elderly woman who was found to have PRL after evaluation for persistent low-grade fever. Diagnostic and therapeutic caveats are discussed on the basis of a critical literature review of case reports and descriptions of small series of patients.