PMC6744820_01
(a) Axial computed tomography showing erosion in the right hypoglossal canal. (b and c) Axial T1- and T2-weighted images showed cystic lesion. (d-f) Gd-diethylenetriaminepentaacetic acid enhanced images showed mild contrast effect.
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F1
Computed tomography (CT) revealed skull base erosion from the right hypoglossal canal to the anterior part of the foramen magnum [Figure 1a]. Magnetic resonance imaging (MRI) revealed a cystic mass lesion in the right hypoglossal canal with high intensity on T2-weighted and FLAIR images, and iso-low intensity on T1-weighted and diffusion-weighted images [Figure 1b and c]. Gd-diethylenetriaminepentaacetate-enhanced images showed irregular high intensity at the lesion periphery [Figure 1d-f].
(a and b) Hematoxylin and eosin staining showing mature hyaline cartilage with well-differentiated chondrocytes.
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F2
Microscopic examination revealed a cartilaginous hyaline matrix and well-differentiated regular shaped cells with a clear cytoplasmic halo [Figure 2a], and no mitotic or pleomorphic cells existed [Figure 2b].