PMC6911675_01
Preoperative magnetic resonance (MR) images: (a) T1-weighted image (T1WI) showing cyst contents as hypointense, (b and c) axial and sagittal T2-weighted images (T2WI) showing a hyperintense cyst in the pons, (d) contrast-enhanced T1WI showing a mural nodule in the cyst, (e and f) subsequent magnetic resonance images (after 1 month) showing cyst enlargement in axial and sagittal T2WI.
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F1
The cystic component appeared as hypointense on the T1-weighted images, hyperintense on the T2-weighted images, and isointense on the diffusion- weighted images [Figure 1a-c]. Although gadolinium administration showed no enhancement of the cyst contents, a small enhancing nodule was visualized [Figure 1d-f].
Intraoperative imaging. (a) Intraoperative images through the microscope showing bilateral cerebellar hemispheres retraction exposing the intact fourth ventricle floor, (b and c) intraoperative images showing the presence of cyst containing milky white viscous fluid and mural nodule. (d) Histopathological examination of the cyst wall showed columnar epithelium containing ciliated cells.
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F2
The floor of the fourth ventricle was covered with the ependymal layer that appeared normal [Figure 2a]. The yellowish-white cyst was detected through the supracollicular safe zone [Figure 2b]. After removing the cyst component by aspiration, the cyst wall and mural nodule were partially removed [Figure 2c]. Therefore, we diagnosed a neurenteric cyst [Figure 2d].
Postoperative imaging after 5 years. (a-c) Magnetic resonance imaging showing small residual cyst in the brainstem on T1WI and T2WI.
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F3
At the last follow-up (5 years after surgery), she was asymptomatic, and there was no evidence of recurrence on follow-up MRI [Figure 3].