PMC3420471_01
Axial (a) and sagittal (b) T1-weighted MRI with gadolinium and axial (c) T2-weighted MRI before surgery revealing a large cystic lesion of left CPA with enhancement of lower portion of the lesion and severe compression of forth ventricle and brainstem.
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fig1
Magnetic resonance imaging (MRI) revealed a large cystic lesion of CPA, hypointense on T1-weighted image, and hyperintense on T2-weighted image, extending to the left parapontine, with partial enhancement of the capsule after intravenous administration of gadolinium (Figure 1).
Axial (a) T1-weighted MRI with gadolinium and coronal; (b) T2-weighted MRI after the first surgery showing growth of the heterogeneous lesion with predominant enhancement and invading the surrounding structures.
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fig2
MRI demonstrated a large heterogeneous mass isointense on T1-weighted image, hyperintense on T2-weighted image, strongly enhanced after gadolinium, extending to the upper medulla oblongata with hydrocephalus and unusual edema (Figure 2).
Malignant squamous cell carcinoma arising from the epidermal cyst, with mitotic activity and cellular atypia (hematoxylin and eosin, original magnification x400).
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fig3
These areas of typical epidermal cyst were juxtaposed with zones that displayed marked nuclear irregularity with mitotic activity and an infiltrative growth pattern (Figure 3).