MR imaging characteristics of a neurenteric cyst.

A 34-year-old man presented with a 2-year history of progressive bilateral leg weakness , paresthesias, and gait incoordination. Of later onset was nocturnal enuresis. On admission to the medical center, a cystometrogram revealed spastic neurogenic bladder. Physical examination demonstrated symmetrical patchy areas of decreased pinprick sensation below the T4 level. Four beats of clonus were elicited at the right ankle, and sustained clonus was noted on the left. There was a left Babinski sign , and the gait was broad and awkward. Metrizamide myelography performed via lateral cervical puncture revealed a ventral intradural extramedullary mass extending from the C6 to the T2 level (Fig. 1 A). The cervical spinal cord was displaced posteriorly and severely flattened . There was an incomplete block to the caudal flow of contrast at T2 . CT myelography of the cervicothoracic spine better defined the fusiform , hypodense, extramedullary soft-tissue mass (Fig. 1 B). MR imaging of the cervicothoracic spine was performed by using a 0.5-T superconductive imager' with a bore size of 100 cm. A flat-surface receiving coil was placed over the region of interest and spin-echo images were acquired at 530/30 (TR/TE) (Fig . 1 C) and at 2120/60,120 (Fig. 10). These revealed the lesion to be hypointense relative to spinal cord but slightly brighter than CSF on 530 T1-weighted images, and hyperintense relative to spinal cord and CSF on both 60 and 120 images at TR = 2120. The lesion was seen clearly to lie ventral to and separate from the cord. Surgery was performed via anterior approach. The C6-C7 and C7 T1 intervertebral disks along with the C7 vertebral body were removed. The dura was identified and incised longitudinally in the midline. Immediately, a large cystic mass deep to the dura and anterior to the spinal cord bulged forward. The cyst was punctured with a 25gauge needle, but attempts to aspirate the gelatinous fluid were unsuccessful. The cyst wall was then widely opened and a mucoidtype material exuded forth, resulting in rapid collapse of the cyst wall. The mid-posterior wall of the cyst was found to be attached to the ventral pia of the spinal cord. The exposed cord was flattened . The cyst wall was removed in its entirety and sent for pathologic study. Biochemical analysis was not performed on the mucoid aspirate .