PMC7749947_01
(a) Computed tomography (CT) scan, sagittal view, bone window showing the clival cyst (b) CT scan, sagittal view showing the clival cyst communicating with subarachnoid space (c) CT scan, bone window showing the clival cyst (arrow) (d) CT scan, bone window showing the clival cyst communicating with arachnoid space (e) magnetic resonance imaging (MRI), T2 sequence, axial cut (f) MRI, T1 sequence, axial view with contrast. (G) MRI, T1 sequence, sagittal view with contrast (h) MRI, T1 sequence, sagittal view (i) MRI, diffusion-weighted imaging sequence, axial view showing no restriction (j) MRI, T2 sequence, axial cut showing the clival cyst (k) MRI, T2 sequence, axial cut showing the cyst communicating with subarachnoid space (l) MRI, T2 sequence, sagittal cut showing the clival cyst communicating with subarachnoid space (m and n) Postoperative imaging post cyst drainage and cystic wall resection, the cystic cavity filled with fat graft (o) Intraoperative view of the endoscopic transnasal approach showing the cystic cavity in the clival cyst after anterior wall opening (p) Intraoperative view showing the cystic wall.
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F1
The brain magnetic resonance imaging (MRI) [Figure 1 a-n] showed a well-defined mildly expansile bone lesion in the clivus with low T1 and high T2 signal intensity with nearly complete suppression of signal intensity on fluid attenuated inversion recovery. The superior margin of the clival lesion was identified by neuronavigation, and then trepination of the anterior portion of the clivus was performed using a high-speed drill [Figure 1 o-p].
The cyst wall consisted of thick fibrous tissue with scattered foci of hemosiderin deposition (arrow, H and E, magnification power x100).
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F2
Microscopy [Figure 2] confirmed fragments of bone with focal degeneration and fragments of fibrous tissue with foci hemosiderin deposition (indicates old hemorrhage).