A 63-year-old woman with a history of acute onset trigeminal neuralgia.
A
B
C
What is your diagnosis?
A. Petrosal apex tumor
B. Mucocele
C. Cholesterol granuloma
D. Petrous apex cephalocele
?
？
？
The answer is Petrous apex cephalocele
Petrous apex cephalocele is a rare lesion representing the protrusion of arachnoid or dura mater from Meckel’s cave into the petrous apex.
It is thought to be caused by increased intracranial pressure, and it is associated with an empty sella.
Axial FIESTA MRI shows bilateral extension of Meckel’s cave to the petrous apex (A, arrows).
The lesions are isointense to the CSF and appear more prominent on the right side.
Axial T2WI and sagittal T1WI show coexistent bilateral optic nerve sheath CSF space enlargement (B, arrows) and a partially empty sella (C, arrow) due to chronic intracranial hypertension.
中文版：
女性，63歲，突發三叉神經痛
診斷？
A. 巖尖腫瘤
B. 粘液囊腫
C. 膽固醇性肉芽腫
D. 巖尖腦膨出
診斷：巖尖腦膨出
顳骨巖尖腦膨出是指顱內蛛網膜或硬腦膜通過Meckel氏腔突入巖尖部，該病罕見。
病因被認為是顱內壓增高，常合併空蝶鞍。
橫斷位FIESTA序列表現為雙側Meckel氏腔延伸至巖尖部（A,箭頭）。
病變信號與腦脊液相似，右側更為顯著。
橫斷位T2WI與矢狀位T1WI可見雙側視神經鞘蛛網膜下腔增寬（B,箭頭）及部分空蝶鞍（C,箭頭），這主要與長期顱內壓增高有關。
From AJNR Classic Case