Primary renal lymphoma. Does it exist?

Although secondary renal involvement from systemic lymphoma is common, primary lymphoma of the kidney is not well recognized. One case is reported and 27 cases purported to be primary tumors are reviewed. From these cases three conclusions have been drawn: it is reasonable to assume that renal lymphoma can be a primary lesion; almost all patients with primary renal lymphoma will develop extrarenal lymphomatous disease shortly after diagnosis of their renal tumor; and survival for more than 1 year after diagnosis is rare.