title: Hypertrophic Olivary Degeneration: A Neurosurgical Point of View.
abstract: Hypertrophic olivary degeneration (HOD) is a rare form of transsynaptic degeneration characterized by hypertrophy of the inferior olivary nucleus situated in the olivary body, part of the medulla oblongata, representing a major source of input to the cerebellum. HOD typically results from focal lesions interrupting connections from the inferior olive within the dentato-rubro-olivary pathway, a region also known as the triangle of Guillain-Mollaret (TGM) (red nucleus, inferior olivary nucleus, and contralateral dentate nucleus). Clinically, HOD presents classically as palatal tremor and can include dentatorubral tremor and/or ocular myoclonus. The pathologic changes associated with HOD feature radiologic changes with the inferior olivary nucleus appearing larger and increasing its T2-weighted signal intensity on magnetic resonance images. HOD is commonly managed with pharmacotherapy but may require surgical intervention in extreme cases. HOD has been found to develop as a consequence of any injury that disrupts the TGM pathways (e.g., pontine cavernoma).These findings highlight the critical importance of a thorough knowledge of TGM anatomy to avoid secondary HOD. We present a patient who developed HOD secondary to resection of a tectal plate cavernous malformation and review the literature with an emphasis on the current knowledge of this disorder.
authors.affiliation: Department of Neurosurgery, Schwarzwald-Baar Klinik, Academic University Hospital of Freiburg, Villingen, Germany.
authors.forename: Carlos Henrique
authors.initials: CH
authors.lastname: Carvalho
authors.affiliation: Department of Neurology, Schwarzwald-Baar Klinik, Academic University Hospital of Freiburg, Villingen, Germany.
authors.forename: Hubert
authors.initials: H
authors.lastname: Kimmig
authors.affiliation: Department of Functional Neurosurgery, University of São Paulo, São Paulo, Brazil.
authors.forename: William Omar Contreras
authors.initials: WO
authors.lastname: Lopez
authors.affiliation: Department of Neurosurgery, Schwarzwald-Baar Klinik, Academic University Hospital of Freiburg, Villingen, Germany.
authors.forename: Manfred
authors.initials: M
authors.lastname: Lange
authors.affiliation: Department of Neurosurgery, Schwarzwald-Baar Klinik, Academic University Hospital of Freiburg, Villingen, Germany.
authors.forename: Reinhard
authors.initials: R
authors.lastname: Oeckler
mesh_terms: D005260:Female; D020233:Gait Disorders, Neurologic / Q000209:etiology / Q000601:surgery; D020786:Hemangioma, Cavernous, Central Nervous System / Q000150:complications / Q000601:surgery; D006801:Humans; D006984:Hypertrophy; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D019636:Neurodegenerative Diseases / Q000473:pathology / Q000601:surgery; D019635:Neurosurgical Procedures / Q000379:methods*; D009847:Olivary Nucleus / Q000473:pathology* / Q000601:surgery*; D011183:Postoperative Complications / Q000473:pathology