Article Figures & Data
Figures
- Fig 1.
C1-occipital JAC encroaching on the hypoglossal canal internal ostium of patient 1. The patient was a 56-year-old man with a 3-month history of tongue weakness. The T2-hyperintense JAC (large arrows) encroachment of the hypoglossal canal internal ostium (arrowhead) and lobular cyst projections (small arrows) from the C1-occipital joint are best seen on T2-weighted coronal (A) and sagittal (B) images. C, Postcontrast T1-weighted coronal image shows JAC thin rim enhancement (large arrow).
- Fig 2.
C1-occipital JAC extending into hypoglossal canal of patient 12. The patient was a 64-year-old man with a 9-month history of tongue weakness, dysarthria, and dysphagia. A, MR T2-weighted axial image shows an extradural hyperintense JAC with a thin hypointense rim extending through the hypoglossal canal (large arrows). B, Oblique T2-weighted image parallel to the hypoglossal canal shows the JAC extension through the hypoglossal canal (large arrow) and contiguity with the C1-occipital joint through a thin lobular extradural projection (arrowheads). C, Postcontrast T1-weighted coronal image shows cyst rim enhancement (large arrows). D, CT sagittal bone reconstruction at the hypoglossal canal external ostium shows secondary canal widening (arrows).
- Fig 3.
Retro-odontoid pseudotumor of patient 2. This patient was an 87-year-old woman with a 2-month history of dysphagia. MR imaging sagittal views show the retro-odontoid soft tissue mass (large arrows) to be T2 hypointense (A), and nonenhancing (B). C, Axial T1-weighted image shows isointense soft tissue eroding the skull base (large arrow) with encroachment of the hypoglossal canal (arrowhead). CT axial soft tissue (D) and coronal bone (E) reformations show hyperattenuated pseudotumor mass (D, large arrow) causing bone erosions (small arrows), with extension into the hypoglossal canal (E, arrowhead). F, For patient 8, axial enhanced T1-weighted image shows retro-odontoid mass heterogeneous enhancement (arrow), as seen in 3 of our 4 patients with ROFPs.
- Fig 4.
C1-occipital osteophyte of patient 7. This patient was a 77-year-old man with a 3-month history of tongue weakness and dysarthria. CT axial (A) and coronal (B) images show severe C1-occipital arthrosis with osteophyte encroachment at the hypoglossal canal external ostium (arrows).
