Magnetic resonance imaging in myelocystoceles. Report of two cases.

Two cases of terminal myelocystocele, a rare localized cystic dilatation of the caudal spinal central canal, are reviewed. Magnetic resonance imaging is a useful diagnostic tool for its evaluation. Terminal myelocystocele consists of the following: a myelocystocele which contains a "trumpet-like" flaring of the distal spinal cord central canal and thus is partially lined by ependymal tissue; a meningocele or dilated subarachnoid space located around the myelocystocele, which bulges into the subcutaneous region; and fibrolipomatous tissue surrounding the two cysts. This condition is usually associated with abnormalities of the vertebral column and sacrum as well as compression of the spinal cord and meningocele by a fibrous band. There is a possible relationship of the myelocystocele to teratogens such as loperamide HCl and retinoic acid, although the exact etiology of this entity is not known.