There is a large heterogeneous mass lies within the left adrenal bed that has heterogeneous and mostly peripheral enhancement on portal venous phase (up to 170 HU). A large portion of the central lesion does not visibly enhance. The spontaneous Hounsfield unit reading measures approximately 20, inconsistent with macroscopic fat. There is retained enhancement on the delayed phase.
The lesion is inseparable from the left adrenal gland. It does not obviously arise from the adjacent left kidney, which itself enhances normally.
There is a 9 mm enhancing nodule medial limb right adrenal gland. Too small to obtain an accurate Hounsfield unit reading on the precontrast study.
The right kidney is normal.
No retroperitoneal lymphadenopathy.
Conclusion: Left retroperitoneal mass is likely of adrenal origin. The differential diagnosis includes phaeochromocytoma and adrenal carcinoma, however, the bilateral nature of the process makes the later less likely.