Neural tube defects (NTD) are perhaps the most frequently occurring congenital anomalies. The incidence is 1:1000 births, but variable throughout the world. They usually occur during 3rd - 4th gestational weeks. Embryologically, a failure of or defective neural tube formation results in NTD. They may occur focally or at multiple points [3
Spina bifida is a term used to describe the NTD occurring in the spine. It is classified as occulta and cystica/aperta. Spina bifida occulta is a skin covered defect of the vertebral arches without neuronal involvement. Very often found in the lumbo-sacral region and accounts for 10% of otherwise normal individuals. The associated neurological dysfunction is absent or negligible. It can be identified as a tuft of hair, a hemangioma, a sinus etc. at lower back. Spina bifida cystic/aperta is a severe form of NTD and characterized by a defect of vertebral arches through which meninges and the neuronal tissue protrudes into a sac. They often associated with neurological deficits. Meningomyelocele is usually associated with Arnold-chiari malformations and hydrocephalus in more than 90% of cases [3
]. Myelomeningocele is the frequently occurring spina bifida whereas terminal myelocystocele accounts for 4-8% of all cases of spinal dysraphism. Antenatal detection of the myelocystocele remained challenging as to its differential diagnosis [3
MRI, both fetal and after birth, is an important diagnostic tool for the index condition. It can delineate a cystic mass with septation in a coronal view. In sagittal view it can show the continuation between central canal of the spinal cord and the inner cyst. The communication of the outer cyst with subarachnoid space can also be visualized. The other spinal and cord anomalies like tethered cord, diastematomyelia, Arnold-chiari malformations, syringocele etc. can also be detected with this tool. Antenatal ultrasonography in expert hands can delineate spinal dysraphism but it is very difficult to diagnose myelocystocele with accuracy even if performed after birth [4
Myelocystocele have been reported in cervical, thoracic and lumbosacral regions. Cervical myelocystocele is infrequently associated with neurological deficit whereas terminal myelocystocele is considered to have more neurological problems [6
]. Our case was an isolated myelocystocele with no neurological problem.
To summarize, myelocystocele is a rare spinal dysraphism and rarer still is an isolated terminal myelocystocele with very negligible neurological deficit. MRI can diagnose the condition in-utero as well as postnatally. Excellent outcome can be achieved by an early repair of the defect.