PMC9699842_01
T2 FLAIR Axial MRI - Preoperative image of a fourth ventricular epidermoid cyst.
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F1
A 33-year-old woman underwent a redoresection for a fourth ventricular epidermoid cyst which had previously been operated on 4 years prior [Figure 1].
Postoperative computed tomography head 2-months after resection - (a) enlarging pseudomeningocele and (b and c) development of ventriculomegaly.
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F2
A repeat CT showed development of moderate hydrocephalus and the progressive enlargement of the suboccipital pseudomeningocele [Figure 2].
Magnetic resonance imaging brain w/wo contrast - (a and b) leptomeningeal enhancement concerning for meningitis and (c) progression of enhancement.
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F3
An magnetic resonance imaging (MRI) brain with contrast was also obtained and demonstrated leptomeningeal enhancement concerning for meningitis [Figure 3].
Magnetic resonance imaging (MRI) brain w/wo contrast - images obtained at time of most recent admission (a) axial T2 MRI w/o contrast, (b) axial T1 MRI w/contrast, and (c) axial T1 MRI w/contrast. Demonstrate a persistent pseudomeningocele with new parenchymal involvement and progression of leptomeningeal enhancement.
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F4
MRI brain with contrast showed increased nodular leptomeningeal enhancement, and the interval development of multiple peripherally enhancing lesions throughout the brain parenchyma, the largest of which measured 1.4 cm within the left caudate [Figure 4].
Histopathological findings - (a) cyst lined by squamous epithelium with granular layer containing laminated keratin, consistent with epidermoid cyst. (b) Adjacent relatively uninvolved cerebellar parenchyma. (c) Necrosis with inflammation, granulation tissue, and giant cells. (d) Degenerating keratinocytes with inflammation and histiocytic reaction.
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F5
Tissue obtained shows cerebellar parenchyma with epidermoid cyst, chronic inflammation, necrosis, granulation tissue, and foreign body reaction with degenerating keratin debris [Figure 5].
Postoperative magnetic resonance imaging brain axial T2 - (a and b) vasogenic edema throughout posterior fossa and brainstem. Decreased ventricular caliber.
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F6
A postoperative MRI brain was obtained which demonstrated worsening vasogenic edema within the posterior fossa and brainstem [Figure 6].