Fig. 2
From: Multimodality imaging of renal lymphoma and its mimics

Solitary mass of renal lymphoma. Axial contrast CT (a) demonstrates a solitary mass (arrow) in the right kidney with avid radiotracer uptake on F18-FDG PET/CT (b), as well as retroperitoneal adenopathy (arrowhead). This is consistent with solitary renal lymphomatous mass in this patient with marginal zone lymphoma. The marked FDG avidity differentiates it from typical renal cell carcinoma which can be mildly FDG-avid