Illustrate the clinico-radiologic correlation of palatal tremor and eight-and-a-half syndrome following a pontine cavernoma hemorrhage and resection, highlighting the role of the Guillain-Mollaret triangle in delayed-onset palatal myoclonus.  

We present a video case report of a 39-year-old woman with a family history of Cerebral Cavernous Malformations associated with CCM1 mutation, who was found to have several cavernomas located in the left parietal lobe and right dorsal pons. She experienced hemorrhage of the right pontine cavernoma complicated by edema, compression of the 4th ventricle, intractable nausea and vomiting, and left sided loss of sensation. She underwent surgical resection, after which the patient developed right abducens and right facial nerve palsies, and right internuclear ophthalmoplegia (INO). Three years post-resection the patient began noticing a clicking sound in her mouth at night.

The video shows the source of the patient's new symptom: delayed development of palatal myoclonus. Her examination also demonstrates limited adduction and abduction of the right eye with limited adduction and full abduction with associated nystagmus on left gaze consistent with right one-and-a-half syndrome; in combination with right CN VII palsy forming an eight-and-a-half syndrome. Additionally, she demonstrates left hemiataxia with ataxic gait. MRI images demonstrate a right pontine cavernoma with ipsilateral hypertrophic olivary degeneration due to lesion of the Guillan-Mollaret triangle.