Anatomy, etiology, and graphic imaging findings of hypertrophic olivary degeneration – description of 10 cases
Authors:
D. Bondar 1*; H. Zítek 1*; D. Ospalík 2; R. Bartoš 1,3; M. Sameš 1; J. Klener 4; V. Němcová 3; M. Derner 5; J. Vymazal 6
Authors‘ workplace:
Neurochirurgická klinika Univerzity J. E. Purkyně, Masarykova nemocnice, KZ a. s., Ústí nad Labem
1; Neurologické oddělení, Masarykova nemocnice, KZ a. s., Ústí nad Labem
2; Anatomický ústav 1. LF UK, Praha
3; Neurochirurgické oddělení, FNMH –Homolka, Praha
4; Radiodiagnostická klinika Univerzity J. E. Purkyně, Masarykova nemocnice, KZ a. s., Ústí nad Labem
5; Radiodiagnostické oddělení, FNMH –Homolka, Praha
6
Published in:
Cesk Slov Neurol N 2026; 89(5): 320-326
Category:
Original Paper
doi:
https://doi.org/10.48095/cccsnn2026320
Overview
Aim: Hypertrophic olivary degeneration (HOD) is a rare form of transsynaptic degeneration resulting from damage to the dentato-rubro-olivary pathway, also known as the Guillain--Mollaret triangle (GMT). This study aims to describe the anatomical relationships, etiology, clinical manifestations, and evolution of MRI findings in patients with HOD. Patients and methods: We retrospectively analyzed 10 patients with MRI findings of HOD from two neurosurgical centers. The etiology and location of the primary GMT lesion, laterality of degeneration, clinical manifestations, and evolution of morphological and signal intensity changes in the inferior olivary nucleus on follow-up MRI were evaluated. Results: Hemorrhage was the most common cause of HOD (7 cases; 70 %), followed by surgical injury to GMT structures and a probable ischemic pontine lesion. HOD was ipsilateral to the primary lesion in 6 patients, contralateral in 2, and bilateral in 2. Typical clinical manifestations were observed in only 3 patients (30 %), including palatal tremor in one patient and ocular myoclonus in two. Follow-up MRI demonstrated regression of signal abnormalities or development of inferior olivary atrophy in 7 patients (70 %). Conclusions: HOD is a characteristic radiological consequence of GMT injury and frequently occurs without typical clinical symptoms. Knowledge of the anatomy of the dentato-rubro-olivary circuit enables the correct interpretation of lesion laterality and differentiation of HOD from neoplastic, ischemic, demyelinating, or inflammatory lesions. Recognition of HOD and its temporal evolution is important for accurate diagnosis and neurosurgical planning in the brainstem and cerebellar regions.
Keywords:
brain MRI – cavernoma – hypertrophic olivary degeneration – Guillain-Mollaret triangle – palatal myoclonus – pontine lesion
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Paediatric neurology Neurosurgery NeurologyArticle was published in
Czech and Slovak Neurology and Neurosurgery
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