Background:

Spinal dysraphism is characterized by failure of fusion at dorsal midline structures through the embryonic developmental stages. A terminal myelocystocele consists of a skin-covered lumbosacral spina bifida and meningocele that directly continuous with the spinal subarachnoid space.

Observation:

A 43-year-old woman who was diagnosed at birth with myelocystocele in the lower segments of the lumbar spine. She was not operated in the early stages of life. At the 43th years of her old, during 9-months, the sac began to progressively increase in size. In our initial examination before surgery, an extremely large skin-covered myelocystocele sac was observed in the thoracolumbar with a diameter of approximately 60 * 70 * 40 cm. patient operated and sac repaired. More than 20 liter of cerebrospinal fluid drainaged from cyst during surgery.

Lessons:

The mechanism of cyst enlargement is not well understood. Progressive and severe increase in size of unrepaired myelocystocele sac is possible in old ages even without cerebral hydrocephalus.