Large heterogenous mass lesion in the left pararenal space contiguous with the inferior pole of the left kidney. Left kidney and its associated renal vasculature are displaced anterosuperiorly. The mass is extending into the posterior mediastinum. Mild left hydronephrosis and the ureter is encased by the mass lesion. Descending colon is also encased and displaced to the left with associated fat strending. Moderate left pleural effusion.
Conclusion: Appearance of the large heterogenous pararenal mass is most consistent with lymphoma.