The authors report a case of sacral pseudomeningocele discovered by ch
ance in a 29-year old male patient presenting with Marfan's disease. I
n this disease, such abnormalities are common and due to excessive fra
gility. of the dura mater. CT and MRI provide an accurate morphologica
l analysis and a complete evaluation of lumbosacral osteomeningeal abn
ormalities.