INTRAMEDULLARY NEURENTERIC CYST WITHOUT ANY ASSOCIATED MALFORMATION -ONE CASE EVALUATED BY RMI AND ELECTRON-MICROSCOPIC STUDY

A 46 years old woman presented with several years history of low back pain. For five years she suffered from weakness of the left lower limb and three years later she experienced an episode of righ foot weaknes s. She suffered too from occasionnal urinary urgency. The examination showed decreased power and diminished sensory perception in the left l eg. On myelography, a block at L2 level was observed. RMI evaluation s howed an intramedullary cyst in the anterior part of the spinal cord w ithout any enhancement of its wall by the Gadolinium. At operation a t hin-wall cyst was found containing clear fluid. After a biopsy of the wall, a cystosubarachnoid shunt was performed. Histological examinatio n of the surgical sample showed a simple cuboidal epithelium lying on collagen fibrills. Electron microscopic studies showed ciliated cells with a clearly-visible basement membrane. The diagnosis of neurenteric cyst was confirmed. In the postoperative course the patient complaine d about sensory loss of the legs and the perineal area. Six months lat er, she exhibited a sensory disturbance of the feet and the right sacr al area, a motor deficit of the distal left leg without urinary distur bance. Neurenteric cysts are dysraphic lesions which can be observed w ithout other abnormalities. They are usually extramedullary and the in tramedullary forms are very rare: among 5 cases reported in the litera ture, one has been evaluated by RMI. in the absence of enhancement by the Gadolinium, the other possible diagnosis seems an ependymal cyst. Contrary to extramedullary forms the postoperative course of intramedu llary neurenteric cysts are not always eventfull. Because the cyst wal l cannot be removed, repeated RMI are desirable in the follow-up.