Female, 67 years old, with metastatic melanoma to the left sacrum. Evaluate for extent of disease. A 3 x 3 x 2 cm enhancing mass is evident within the left sacral ala. The lesion encroaches slightly upon the left S1 neural foramen. A majority of the lesion is intraosseous, though there is a small extraosseous component tracking inferiorly and anteriorly along the S1 nerve root as it exits the foramen.No definite evidence of any additional metastatic lesion is seen. There are scattered areas of marrow inhomogeneity, for example anteriorly within the L4 vertebral body. However, these areas do not enhance and as there is no correlating bony destruction on the prior CT myelogram, they are favored to be benign. Vertebral body heights are maintained. Spinal alignment is anatomic.The visualized distal spinal cord, conus and nerve roots of the cauda equina are within normal limits. No pathologic spinal cord or leptomeningeal enhancement is seen. No epidural abnormalities are suspected.L1-2: Unremarkable. L2-3: Mild facet arthropathy. Prominently lateral disc bulging. No spinal canal stenosis. Mild bilateral foraminal narrowing. L3-4: Mild facet arthropathy. Mild disc bulging. No spinal canal stenosis. Mild bilateral foraminal narrowing. L4-5: Facet arthropathy and ligamentum flavum thickening. Disc bulging with a superimposed central protrusion. Mild spinal canal stenosis. Mild bilateral foraminal narrowing. L5-S1: Advanced facet arthropathy. No spinal canal or foraminal stenosis.
A metastatic lesion is evident within the left sacral ala. The lesion encroaches mildly upon the left S1 neural foramen. The lesion is predominantly intraosseous, though there is a small extraosseous component which tracks inferiorly and anteriorly along the exiting S1 nerve root.