 The previous large left-sided retroperitoneal mass has markedly decreased in size and the intraspinal portion is no longer apparent. The residual tissue centered along the left anterolateral aspect of the L1-L2 disc space measures approximately 11 x 12 mm, previously approximately 34 x 49 mm. There is small focus of enhancement and T2 hyperintensity within the central T12 vertebral body compatible with basivertebral venous plexus. The vertebral column alignment is within normal limits. The vertebral body and disc space heights are preserved. There is diffuse loss of normal bone marrow signal intensity most compatible with treatment effect and conversion to red marrow. The imaged spinal cord displays normal signal and morphology and the conus terminates at L1-L2. The left-sided hydronephrosis is no longer apparent and the partially imaged hepatic lesions have decreased in number.
1.Marked treatment response with decrease in size of the retroperitoneal mass and resolution of the intraspinal portion.2.Apparent resolution of the left-sided hydronephrosis and improvement in the partially imaged hepatic lesions.3.Diffuse bone marrow treatment response with conversion to red marrow.