Hypertrophic olivary degeneration in a 16-year-old girl after subtotal surgery of a brainstem pilocytic astrocytoma – a case report

Abstract

Purpose Hypertrophic olivary degeneration (HOD) is a unique neurological condition caused by interruption of the dentato-rubro-olivary pathway, also known as the triangle of Guillain and Mollaret. Magnetic resonance (MR) imaging is the best modality to diagnose both the degeneration of the inferior olivary nucleus and the underlying cause. Case report We describe a case of a unilateral HOD in a 16-year-old girl several months after a subtotal excision of a brainstem pilocytic astrocytoma. Taking into account the patient’s history, tumour recurrence must have been considered, but the typical location and MR morphology, as well as the time of occurrence after brainstem surgery, contributed to the diagnosis of HOD. The causative factor was the interruption of the central tegmental tract, which forms one arm of the Guillain and Mollaret triangle. Additionally, this is an interesting case of a child, who stayed in a coma for several months following brainstem surgery, but finally was discharged home with only minor neurological defects and returned to normal life. Conclusions Hypertrophic olivary degeneration is an infrequent neurological condition, especially in the paediatric population. Nevertheless, it should be considered when interpreting late postoperative scans of children with a history of a brain tumour.

Iron deposits in the red nucleus at long-term follow-up after hypertrophic olivary degeneration

“…During the third stage, olivary shrinkage becomes apparent on MRI, although increased T2 signal can persist. In previous studies (6), DWI was considered to show no restricted diffusion; however, in this case, DWI hyperintensity was observed in the left ION 6 months after cerebellar hemorrhage, but isointensity was observed at 11 months, 2 years, and 4 years, suggesting that signals on DTI allows the in vivo investigation of white matter fibers, which assists in analyzing and quantifying changes in DROP white matter fiber tracts in HOD patients. In this case study, the volume of the left CTT was decreased, which was consistent with previous studies (7).…”

Bilateral Hypertrophic Olivary Degeneration Following Brainstem Insult: A Retrospective Review and Examination of Causative Pathology

“…[1][2][3][4] The majority of literature surrounding this disease has been composed of case reports and small case series, the majority of which have highlighted the apparent predilection for the development of unilateral HOD. 8,11,12,17,18 Recently, authors from large tertiary referral centers have published retrospective series of all patients who were diagnosed with HOD; revealing a significant percentage of cases are actually bilateral. 9,10 Contrary to what would be expected given our current understanding of the pathogenesis of HOD, these studies showed that in 2 series of 102 and 95 patients, 76% and 59% of all cases showed bilateral findings, respectively.…”