The clinical and neuroradiological features of hypertrophic olivary degeneration following brainstem stroke.

OBJECTIVES

Hypertrophic olivary degeneration (HOD), a rare type of trans-synaptic degeneration of the central nervous system (CNS) caused by disruption of the dentato-rubro-olivary pathway (DROP), is mainly described in the form of case reports. Our aim in this study is to summarize the clinical and imaging characteristics of patients with HOD following brainstem stroke.

METHODS

A retrospective analysis was performed for all patients who were selected from electronic case databases between October 2019 and January 2024 in the Jiangxi Provincial People's Hospital and the Xinyu People's Hospital. The clinical data of included patients were summarized by our experienced neurologists. Besides, we analyzed the anatomical pathways between primary lesions in the brainstem and subsequent HOD.

RESULTS

A total of 11 patients, including 2 females and 9 males, were included in this retrospective study. HOD associated clinical presentations consisted of Holmes tremor (HT) (n = 6), palatal tremor (PT) (n = 4), cerebellar ataxia (n = 4), and nystagmus (n = 4). On initial MRI, pontine and midbrain lesions were found in 10 and 1 patients, respectively. Upon follow-up neuroradiological evaluation, unilateral and bilateral HOD appeared in 6 and 5 cases, respectively. Isolated mesencephalic lesion might lead to bilateral HOD, which was due to the involvement of the decussation of the superior cerebellar peduncle (SCP).

CONCLUSION

For HOD associated clinical presentations, HT and cerebellar ataxia were the commonest. Unilateral pontine lesions might give rise to both unilateral and bilateral HOD, whereas bilateral HOD caused by isolated mesencephalic lesion was extremely rare.