Knowing that this patient had a previous haemorrhagic lesion on the area of the right cerebellar dentate nucleus, what is the most likely diagnosis for the hypersignal on T2/FLAIR at the left anterolateral aspect of the pons?
Hypertrophic olivary degeneration.
What are the three corners of the triangle of Guillain and Mollaret?
1) red nucleus 2) inferior olivary nucleus 3) contralateral dentate nucleus
What is the cause for hypertrophic olivary degeneration?
Interruption of either of the connections between the dentate nucleus and contralateral red nucleus (dentatorubral tract, superior cerebellar peduncle) or the connection between the red nucleus and ipsilateral inferior olivary nucleus (central tegmental tract) leads to changes in the olive.
Rounded T2/FLAIR hyperintensity in the left inferior pons. This is consistent with hypertrophic olivary degeneration related to a contralateral dentate nucleus lesion.