Neuropediatrics 2013; 44 - PS21_1137
DOI: 10.1055/s-0033-1337866

Hypertrophic olivary degeneration: a differential diagnosis to consider following surgical intervention in the posterior cranial fossa: review and two case reports

S Walsh 1, J Schallner 1, L Freudenberg 1, M Smitka 1, M von der Hagen 1, M Warmuth-Metz 2, G Hahn 3
  • 1TU Dresden, Abteilung Neuropädiatrie, Dresden, Germany
  • 2Universitätsklinikum Würzburg, Abteilung Neuroradiologie, Würzburg, Germany
  • 3TU Dresden, Klinik und Poliklinik für Radiologie, Dresden, Germany

Objective: Hypertrophic olivary degeneration (HOD) is a rare trans-synaptic degeneration that follows lesioning of the dentatorubral olivary pathway in the myoclonic (Guillain-Mollaret) triangle. It is characterized by variable enlargement of the olivary nucleus, and often occurs about 3 weeks after lesioning caused, for example, by cerebral bleeding, infarction, tumor, or neurosurgical intervention, especially in the posterior cranial fossa. In the MRI, an intense area in T2 in the lower olivary nucleus can be observed. We report on two juvenile female patients (P1, P2) with typical MRI changes following surgical intervention in the posterior cranial fossa.

Case Reports: P1 is a 10-year-old girl who was diagnosed with a medulloblastoma (WHO grade IV). Seven months after partial tumor resection, radiation, and the start of chemotherapy, the MRI showed in T2 a hyperintense area in the left medulla oblongata with contrast-medium enhancement, consistent with HOD.

P2 is a 12-year-old girl who was admitted following right hemiparesis and double vision. The MRI showed a bleeding cavernoma in the brainstem, including the pons and left mesencephalon. Because of progressive bulbar symptoms, the patient needed a neurosurgical intervention. Nine months later, a hyperintense lesion in T2 was found in the area of the lower olivary nucleus, with minor contrast medium enhancement.

Discussion: To date, there have been few reports on HOD following surgical intervention in the posterior cranial fossa. Most of the time, HOD is only seen on one side and there is no description of contrast-medium enhancement. It is important to be able to differentiate a rare disease such as HOD from other, more common ones, such as metastasis, other neoplasias, inflammation or infection, ischemia, or toxic effects after radiation. Importantly, contrast-medium enhancement, as described in the above cases, should not exclude the possible diagnosis of HOD.