case_images: PMC6744820_01
case_images: (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.
case_images: SNI-10-63-g001.jpg
case_images: PMC6744820_01_SNI-10-63-g001.jpg
case_images: F1
case_images: 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].
case_images: (a and b) Hematoxylin and eosin staining showing mature hyaline cartilage with well-differentiated chondrocytes.
case_images: SNI-10-63-g002.jpg
case_images: PMC6744820_01_SNI-10-63-g002.jpg
case_images: F2
case_images: 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].