Left lower back pain/buttock pain. Additional history includes known renal cell carcinoma metastases. Five lumbar type vertebral bodies are present. There is diffuse enhancement and edema in the left sacral ala, which has increased in extent since 7/28/2016. Although there is some linear signal abnormality in the anterior aspect of the left sacroiliac, the degree of increased edema and enhancement is suggestive of underlying increasing tumor infiltration. Edema and enhancement surrounds the extraforaminal left L5 nerve root as well as left sacral foraminal nerve roots, without evidence of significant compression.There is redemonstration of a large mass involving the right aspect of the sacrum centered at the right S2 level. Decreased central enhancement of the lesion and now predominantly peripheral enhancement suggests necrosis. The tumor surrounds the right S2 nerve root and to a lesser degree S3 and S1 roots. The previously demonstrated epidural extension is no longer evident. Small enhancing lesions at the anterior superior aspect of the L2 vertebral body is slightly increased, measuring 9 mm on today's examination. A smaller lesion in the posterior aspect of the L2 vertebral body is slightly smaller. The enhancing lesion in the right articular process of L4 has minimally increased in size. The small T12 spinous process enhancing lesion appears grossly stable. Enhancing lesions in both iliac bones were better assessed on prior MR of the pelvis. Elsewhere in the lumbar spine, no large lesions are evident. Vertebral body heights are within normal limits. There is trace anterolisthesis of L5 on S1. Alignment is otherwise within normal limits. The conus medullaris is normal in position.Multilevel degenerative changes are seen, as described below:L1-L2: There is mild disc bulge, ligamentum flavum thickening, and bilateral facet arthropathy. There is no significant spinal canal stenosis. No significant neural foraminal stenosis.L2-L3: There is mild disc bulge, ligamentum flavum thickening, and bilateral facet arthropathy. There is no significant spinal canal stenosis. No significant neural foraminal stenosis.L3-L4: There is mild disc bulge, ligamentum flavum thickening, and bilateral facet arthropathy. There is no significant spinal canal stenosis. There is minimal bilateral neural foraminal narrowing.L4-L5: There is loss of disc height, disc bulge, ligamentum flavum thickening, and advanced bilateral facet arthropathy. There is resulting moderate to severe spinal canal stenosis. There is moderate bilateral neural foraminal narrowing, worse on the left.L5-S1: Grade 1 anterolisthesis with disc uncovering. There is advanced bilateral facet arthropathy. There is partial effacement of the lateral recesses. No significant central canal stenosis. There is minimal right and mild to moderate left neural foraminal stenosis.A large left renal cortical cyst is visualized.
1. Decreased central enhancement and epidural spread of the large right sacral metastatic lesion is compatible with interval treatment changes.2. Increasing edema and enhancement in the left sacral wing with small linear signal changes in the anterior portion suggest developing stress fracture with findings suspicious for underlying infiltrating tumor. Enhancement and edema surrounding the L5 and sacral nerve roots on the left without significant compression.3. Additional small lesions in the lumbosacral spine overall appear relatively stable with some lesions slightly smaller and some slightly larger. No large new lesion in the lumbar spine or evidence of new epidural tumor extension.4. Redemonstrated multilevel degenerative changes in the lumbar spine with moderate to severe spinal canal stenosis at the L4-L5 level, without significant change since 2/22/2016. Additional details as above.