Sacral abnormalities in Marfan syndrome.

Five women with Marfan syndrome had abnormalities of the sacrum disclosed by computed tomography. Each had evidence of expansion of the central sacral spinal canal and enlargement of sacral foramina associated with extensive bony erosion. Three patients complained of low back pain, two were asymptomatic. Sacral meningoceles were demonstrated in three cases (including two of the three with symptoms). A fourth patient had a thoracic meningocele. The sacral abnormalities are attributed to defective collagen resulting in expansion of weakened dura which leads to pressure erosion of contiguous osseous structures.