This is a rare case of hypertrophic olivary degeneration (HOD) in a patient with previous history of pontine hemorrhagic infarct. 

HOD is a rare condition characterized by a unique pattern of trans-synaptic degeneration caused by damage dentato-rubro-olivary pathway. This disease process is different from all other types of neuronal degeneration in that the main pathophysiology is hypertrophy of neurons. 

Differential diagnosis:

• infarction
• neoplasms: primary or secondary
• demyelination
• infections