Perirenal Lymphoma

Fig. Axial CT with IV contrast shows a rind of enhancing soft tissue in the posterior aspect of the left perirenal space (left arrow), and nodular thickening of the posterior pararenal fascia (right arrow). The patient has a known, treated Burkitt lymphoma.

Lymphoma and Kidneys

• Usually extranodal sites of lymphoma
• Primary renal lymphoma very rare
• Renal involvement usually in late disease, and clinically silent
• More common with non-Hodgkin disease

Typical CT Patterns of Renal Lymphoma

1. Multiple masses -- most common, bilateral > unilateral
2. Solitary masses
3. Contiguous retroperitoneal extension
4. Perirenal disease
5. Infiltrative disease - almost always bilateral, preserved renal contour
   

Perirenal Lymphoma
Either from direct extension from retroperitoneal disease, transcapsular spread of renal parenchymal disease, or less commonly lymphoma completely surrounds the kidney

Our case is a biopsy-proven perirenal lymphoma.

Reference:
Urban BA, et al. Renal Lymphoma: CT Patterns with Emphasis on Helical CT. Radiographics 2000;20:197.