PMC9699848_01
Preoperative magnetic resonance imaging (MRI) T1 + c - coronal (upper left) and axial (upper right) view - demonstrating hypointense T1 right cerebellopontine angle lesion, with a small enhanced area on the medial side of the lesion. Preoperative MRI T2 demonstrating hyperintensity on T2-weighted image with focal areas of hypointensities in the periphery (lower left), correlating with keratin. Restricted diffusion is seen on diffusion-weighted image (lower right).
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F1
A small enhancing region was present on the medial side of the lesion [Figure 1].
Demonstrating areas of a simple squamous epithelial cyst with mounds of layered keratin, typical of an epidermoid cyst (H&E stained, x50).
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F2
The first specimen demonstrated areas of simple squamous epithelial cyst with mounds of layered keratin, typical of EC [Figure 2].
Demonstrating areas of proliferating squamous epithelium with thick projections (upper; H&E stained, x50); and areas of MT demonstrating dyskeratotic cells, few mitotic figures (red circled), and necrosis (lower; H&E stained, x100).
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F3
The other specimen contained thickened, proliferating squamous epithelium creating finger-like projections, and containing dyskeratotic and acantholytic cells and foci of necrosis, compatible with SCC [Figure 3].
Magnetic resonance imaging (MRI) T1 + c - axial view - postoperative MRI 11 months following surgical resection demonstrating local massive recurrence (left); and MRI 2 months following radiation therapy (right) demonstrating a decrease in the size of the lesion.
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F4
Eleven months following surgical resection, a follow-up MRI showed a local massive recurrence of the enhancing lesion [Figure 4]. An MRI scan done 2 months after radiation therapy showed a decrease in the size of the recurring lesion [Figure 4].