PMC5343612_01
The first brain magnetic resonance imaging performed for the patient revealed an extradural posterior fossa mass lesion that was hypointense in T1 (a) and hyperintense in T2, (b) increased signal intensity in diffusion-weighted imaging, (c) and decreased signal intensity in apparent diffusion coefficient map, (d) suggested the diagnosis of an epidermoid tumor
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F1
Craniocervical junction and upper cervical cord signal and thickness were normal [Figure 1].
(a and b) Intraosseous epidermoid cyst contains multiple layers of squamous cells with granular layer and keratinous material (H and E, x100, H and E, x400)
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F2
Microscopic examination showed interosseous epidermal inclusion cysts, filled with keratinous needle-like material [Figure 2].
Two months after previous surgery, brain computed tomography scan revealed a large heterogenous dense mass in the left occipital part of the scalp (a), associated with destruction of the occipital bone (b), brain magnetic resonance imaging showed a heterogenous lesion including cystic and solid components in the left side of posterior fossa (c)
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F3
The brain MRI revealed a heterogenous lesion including cystic and solid components in the left side of the posterior fossa [Figure 3].
(a and b) Squamous cell carcinoma characteristically contains cohesive nests of cells with vesicular nuclear pattern and prominent nucleoli, in addition to eosinophilic cytoplasm. Nuclear pleomorphism, mitotic figures, accessional squamous pearls, and perineural invasion are identifiable elsewhere within this tumor (H and E, x100, H and E, x400)
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F4
The microscopic examination revealed a moderately differentiated SCC [Figure 4].