title: Hypertrophic olivary degeneration secondary to pontine haemorrhage.
abstract: We report a 58-year-old man who developed hyptertrophic olivary degeneration (HOD) after haemorrhage of a cavernous malformation in the pons. Lesions of the triangle of Guillain and Mollaret (the dentatorubro-olivary pathway) may lead to HOD, a secondary transsynaptic degeneration of the inferior olivary nucleus. HOD is considered unique because the degenerating olive initially becomes hypertrophic rather than atrophic. The primary lesion causing pathway interruption is often haemorrhage, either due to hypertension, trauma, surgery or, as in our patient, a vascular malformation such as a cavernoma. Ischaemia and demyelination can also occasionally be the inciting events. The classic clinical presentation of HOD is palatal myoclonus, although not all patients with HOD develop this symptom. The imaging features of HOD evolve through characteristic phases. The clue to the diagnosis of HOD is recognition of the distinct imaging stages and identification of a remote primary lesion in the triangle of Guillain and Mollaret. Familiarity with the classic imaging findings of this rare phenomenon is necessary in order to avoid misdiagnosis and prevent unnecessary intervention.
authors: Department of Radiology, First Floor, 1B Building, The Royal Melbourne Hospital, Grattan Street, Parkville, VIC 3050, Australia. Electronic address: sarawein@bigpond.com.
authors: Sara
authors: S
authors: Wein
authors: Department of Neurology, The Royal Melbourne Hospital, Parkville, VIC, Australia.
authors: Bernard
authors: B
authors: Yan
authors: Department of Radiology, First Floor, 1B Building, The Royal Melbourne Hospital, Grattan Street, Parkville, VIC 3050, Australia; Department of Radiology, The University of Melbourne, Parkville, VIC, Australia.
authors: Frank
authors: F
authors: Gaillard
mesh_terms: D020203:Brain Stem Hemorrhage, Traumatic / Q000150:complications* / Q000473:pathology*; D003951:Diagnostic Errors; D018450:Disease Progression; D020786:Hemangioma, Cavernous, Central Nervous System / Q000150:complications; D006801:Humans; D008297:Male; D008875:Middle Aged; D009207:Myoclonus / Q000175:diagnosis / Q000209:etiology; D009410:Nerve Degeneration / Q000209:etiology* / Q000473:pathology*; D009847:Olivary Nucleus / Q000473:pathology*; D011149:Pons / Q000473:pathology
keywords: Cavernoma; Hypertrophic olivary degeneration; MRI; Palatal myoclonus; Pontine haemorrhage