PMC8247734_01
Pre-operative neuroimaging. (a) Axial computed tomography-head image showing mildly hyperdense large extraaxial mass at the upper aspect of the premedullary cistern extending mildly to the inferior left cerebellopontine angle with compression of the brainstem. (b) Axial magnetic resonance imaging (MRI)-brain T2- fluid-attenuated inversion recovery (FLAIR) image showing hyperintense left premedullary cistern and cerebellopontine angle mass. (c) Sagittal MRI-brain T1-FLAIR image showing isointense premedullary cistern mass. Arrow points to the left premedullary cistern mass later histopathologically confirmed to be a neurenteric cyst.
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F1
Computed tomography (CT) of the head without contrast showed a mildly hyperdense large extra-axial mass at the upper aspect of the premedullary cistern extending mildly to the inferior left cerebellopontine angle with compression of the brainstem [Figure 1a]. T2-fluid-attenuated inversion recovery (FLAIR), well-circumscribed, hyperintense mass in the left cerebellopontine angle and premedullary cistern [Figure 1b]. There was local mass effect on the brainstem without associated edema. The sagittal T1-FLAIR image showed isointense mass [Figure 1c].
Microscopic examination of the cyst lining reveals a pseudostratified ciliated columnar epithelium. (a) Low-magnification hematoxylin and eosin (H and E) staining showing fibromembranous tissue lined by columnar epithelium. Imaged at x4 magnification. (b) High-magnification H and E staining showing pseudostratified ciliated columnar epithelium and adjacent arachnoidal epithelium. Imaged at x40 magnification.
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F2
Post-operative neuroimaging. Computed tomography-head images, axial (a) and sagittal (b), showing empty spaces (arrows) at neurenteric cyst location after fenestration.
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F3
Postoperatively, the patient recovered well, and post-operative CT of the head without contrast showed no residual mass [Figure 3].