Patient Data
Initial scan performed for assessment of giant supra-sellar aneurysm. Patient had VP shunt (into corpus callosum!) for persistent hydrocephalus following hemorrhage.
On the follow-up scan, it is apparent that she has suffered hemorrhage into the pontine tegmentum. High signal and focal swelling is seen in the medulla (left > right).
- Note: This case has been tagged as "legacy" as it no longer meets image preparation and/or other case publication guidelines.
Case Discussion
Hypertrophic olivary degeneration is secondary to trans-synaptic injury along the dentato-rubral-olivary pathway (better known as the triangle of Guillain-Mollaret). It is an unusual type of degeneration because it is associated with enlargement, rather than atrophy, of the inferior olivary neurons. Pathologically, it corresponds to vacuolar degeneration of cytoplasm that results in enlargement.
It is important to recognize this pattern of injury so that the changes in the medulla are not ascribed to a more serious cause, e.g. tumor, demyelination or infarct. The most important clue to the correct diagnosis is the association of a remote lesion along the pathway.