PMC3589834_01
(a) Unenhanced cranial CT performed on admission. The mass is isodense with no visible bone destruction, (b) T1-weighted MRI performed on admission. The mass appears heterogeneously hyperintense, (c) T2-weighted MRI performed on admission. The mass appears more hyperintense than by T1-weighted MRI, (d) Diffusion-weighted images demonstrate that the mass has slightly restricted diffusion, (e) Gadolinium-enhanced axial T1-weighted MRI performed on admission showing no contrast enhancement, (f) Gadolinium-enhanced sagittal T1-weighted MRI performed on admission demonstrate a lesion in the retroclival prepontine location with no contrast enhancement
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F1
The lesion compressed the patient's pons and right abducens nerve [Figure 1].
Operative findings. (a) An image obtained before drilling the clival recess. The patient underwent ETSS, (b) After removing the mucosa of the sphenoid sinus, the clival bone was drilled to entirely expose the mass. The gelatinous and yellowish-brown mass mainly located in the extradural space, (c) The mass is partially located intradurally accompanied with a small dural defect, (d) An image obtained after removal of the mass. The mass is partially removed and decompression is performed. OCR = opticocarotid recess, CP = carotid protuberance, EP = ecchordosis physaliphora, BA = basilar artery
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F2
The intradural mass had compressed the arachnoid mater, which had a yellowish discoloration [Figure 2].
(a) Postoperative gadolinium-enhanced axial T1-weighted MRI obtained 1 week after surgery revealing a residual mass on the right Dorello's canal (arrow), (b) Gadolinium-enhanced axial T1-weighted MRI obtained 4 months after surgery does not reveal a residual mass (arrow head)
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F3
Postoperative MRI demonstrated partial removal of the mass, adequate for decompression [Figure 3]. No residual mass was revealed on MRI [Figure 3].
A pathological examination of the mass showing hypocellular physaliphorous cells with a lobular growth pattern and eosinophilic cytoplasm with vacuolated mucous droplets. Neither mitosis nor dyskaryosis is visible. (H and E, x200)
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F4
Neither mitosis nor dyskaryosis were visible [Figure 4].