Primary small noncleaved cell lymphoma of kidney.

The kidney is the second most common site for metastasis of lymphoma though it remains asymptomatic and is not commonly detected with cross-sectional imaging studies. Primary renal lymphoma is a very rare lesion whose existence is controversial. The lymphoma reported here presented as a solitary renal mass without any other evidence of disease. Lymphoma should be included in the differential diagnosis for solitary renal masses even though the usual presentation is bilateral. Renal involvement with lymphoma requires a thorough search for extrarenal disease.