Benign and malignant lymphadenopathy may exhibit mild (mean, +6 HU) to pronounced (mean, +61 HU) enhancement after intravenous administration of iodinated contrast material with maximal enhancement occurring 1 to 2 minutes after injection.

long black arrow=rim enhancement.

short black arrow=heterogenous enhancement.

this case is renal cell carcinoma.

Reference:BiblioMed Textbook-Computed Body Tomography