2019 Volume 28 Issue 6 Pages 359-364
Spinal extradural arachnoid cysts are caused owing to the flow of cerebrospinal fluid (CSF) through a dural defect that connects the subarachnoid space to a cyst cavity. Symptomatic cases should be treated by repairing the dural defect and removing the cyst cavity. Here we report a case of an extradural arachnoid cyst with a dural defect that was detected preoperatively on three-dimensional (3D) turbo spin-echo (TSE) magnetic resonance imaging (MRI).
The patient, a 72-year-old woman, presented with tingling in her left buttocks and bilateral thigh, which had persisted for three months. MRI revealed imaging characteristic of an arachnoid cyst from Th12 to L3 external to the dura mater, with a signal intensity similar to that of CSF. The diagnosis made was that of an extradural arachnoid cyst.
Preoperative two-dimensional T2-weighted TSE MR images showed no findings characteristic of a dural defect ; however, 3D T2-weighted TSE images (with a variable flip angle) showed a linear hypointense signal that extended laterally at the L1 level from the subarachnoid space to a cyst cavity on the left as a flow void. We suspected that the connection between the flow void in the dura mater and cyst cavity was a dural defect and planned a Th12-L2 laminectomy. After the laminectomy, we found the dural defect at the location expected preoperatively, sutured it, and incised the cyst wall. After the surgery, the patient’s symptoms gradually improved, and postoperative MRI showed no residual or recurrence of the lesion.
This case demonstrates the utility of 3D TSE MR imaging for preoperatively detecting a dural defect of the spinal extradural arachnoid cyst in a noninvasive manner.
