Final pathology diagnosis retroperitoneal mass core biopsy: Diffuse large B-cell lymphoma, of germinal center origin.      

This case illustrates the classic appearance of retroperitoneal lymphomatous infiltration, which lifts the aorta and surrounds vasculature without resulting in significant narrowing of compression. A particularly striking finding in this case is diffusely abnormal bone marrow, with mottled appearance and areas of lucency and sclerosis, suggesting diffuse lymphomatous infiltration of the marrow.