Bilateral lower extremity weakness and metastatic prostate cancer. As on the prior examination, the T12 vertebral body is considered to be the last rib-bearing vertebra. There are 6 nonrib-bearing lumbar-type vertebrae. Mild degenerative grade 1 retrolistheses of L3 on L4 and L4 on L5 are demonstrated. The vertebral body heights are maintained. There is diffuse abnormal bone marrow signal throughout the imaged osseous structures related to metastatic disease. There is epidural extension of tumor throughout the lumbar spine and in the visualized portion of the lower thoracic spine on sagittal images. This results in moderate spinal canal stenosis at the L3 and L4 levels. There is severe spinal canal stenosis at the L5 and L6 levels. There are also multilevel degenerative changes, which have also progressed since the prior examination. The degenerative changes contribute to varying degrees of spinal canal and neural foraminal stenoses. There is moderate to severe spinal canal stenosis related to a posterior disc protrusion and extrusion with mild caudal migration at L4-5 and a central disc protrusion with facet arthropathy at L5-6. There is moderate bilateral neural foraminal narrowing at the L4-5 level as well as moderate right and severe left neural foraminal narrowing at the L5-6 level. There is multilevel disc desiccation and intervertebral disc height loss, which is severe at L4-5. The visualized portion of the distal spinal cord and conus medullaris appear normal in signal and morphology on sagittal images only. There is redundancy of the cauda equina nerve roots above the levels of stenosis at L4-5 and L5-6. At L2 and L3 levels, there is again CSF signal intensity displacing the nerve roots to the left and anteriorly.
1. Abnormal bone marrow signal throughout the imaged axial skeleton has progressed from the prior examination and is compatible with diffuse osseous metastatic disease. Multiple levels of epidural extension contribute to varying degrees of spinal canal and neural foraminal stenosis. The most pronounced degree of spinal canal stenosis is at the L4-5 and L5-6 levels.2. Interval progression of lumbar degenerative disease of the lumbar spine contributing to spinal canal and neuroforaminal stenosis, as described above. 3. Possible arachnoid cyst versus altered cerebrospinal fluid dynamics at the L2 to L3 levels. 