Primary extranodal perirenal malignant lymphoma.

We report 2 cases of primary extranodal perirenal malignant lymphoma. Complete examination of the retroperitoneum confirmed that the disease was confined to the perirenal space and was not associated with nodal or other body site involvement. Previous reports of perirenal lymphoma in the medical literature have based diagnosis on either radiologic findings and past history of malignant lymphoma with or without needle biopsy of the retroperitoneum. Due to circumscription of this lesion by the renal capsule and Gerota's capsule and isolated perirenal findings in early disease, perirenal lymphoma may mimic a renal neoplasm on clinical and radiologic examinations.