Fig. 10

Hypertrophic olivary degeneration. A 69-year-old man with history of hypertension presenting with new onset palatal myoclonus, hoarse voice, and ataxia. Axial T2 (a) and susceptibility-weighted (b) MR images reveal a lesion at the left parasagittal pontomedullary junction at the level of the facial colliculus demonstrating bubbly high T2 signal internally surrounded by a rim of low T2 signal intensity (arrow) and associated blooming (solid arrowhead), compatible with a cavernous malformation. Thin section axial T2 image (c) reveals hyperintensity and expansion of the left inferior olivary nucleus (dashed arrowhead), consistent with hypertrophic olivary degeneration. Lesions involving the dento-rubro-olivary tract (such as this cavernous malformation) can lead to hypertrophic olivary degeneration