PMC4553637_01
Case 1. (a) Preoperative T1-weighted, sagittal plane image: The cyst (arrows) determines biventricular hydrocephalus developing over the third ventricle that is downward displaced (circle); note also the compression of both pituitary gland and its stalk (circle). (b) The postoperative corresponding magnetic resonance image shows the shrinkage of the cyst (arrows), re-expansion of the third ventricle, patency of the foramen of Monro as well as the decompression of pituitary complex (circle)
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F1
In each, computed tomography (CT) scan and magnetic resonance imaging (MRI) showed a giant (diameters in the three-dimensions over 4 cm, the biggest of them over 7 cm), supratentorial cyst of the midline determining biventricular hydrocephalus: In case 1 the third ventricle and brain-stem were downward displaced [Figure 1a]; in case 2 [Figure 2a] the cyst extended to the infratentorial compartment compressing the brain-stem posteriorly.
Case 2. (a) Preoperative magnetic resonance imaging (MRI): The sagittal plane T2-weighted image shows the enormous cyst (arrows) displacing the corpus callosum (CC) and the brain-stem. (b) The corresponding postoperative MRI: After treatment the deflated cyst wall is visible (arrows) and the CC with internal cerebral veins as well as the brain-stem appear decompressed
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F2
In each, computed tomography (CT) scan and magnetic resonance imaging (MRI) showed a giant (diameters in the three-dimensions over 4 cm, the biggest of them over 7 cm), supratentorial cyst of the midline determining biventricular hydrocephalus: In case 1 the third ventricle and brain-stem were downward displaced [Figure 1a]; in case 2 [Figure 2a] the cyst extended to the infratentorial compartment compressing the brain-stem posteriorly.
Endoscopic images during surgery. (a) Step by step the thick capsule (asterisk) is coagulated and fenestrated. (b and c) At the end of the procedure the cyst is clearly reduced and the surrounding anatomical structures, altered by the chronic compression, are visualized: The anterior cerebral and communicating arteries (black arrow), the absence of the septum pellucidum and the fornix of each side (bold arrows). The opened cyst wall and its adherences to the surrounding ependyma (arrows) are visible: Some of them hide dangerous veins (bold arrow)
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F3
At surgery, through a right precoronal burr hole, the frontal horn of the ventricle was entered with a Storz-Decq rigid endoscope (30  angled): Fenestration of the cyst was made and the shrinkage was facilitated by monopolar coagulation of the capsule [Figure 3a and b].