Presentation
Severe headache and giddiness.
Patient Data
Gradient images (GRE) shows a well-defined area of blooming artifact involving the dorsal pons on the right side, which is seen extending across the midline. This area of blooming appears hyperintense on T2W with a hypointense rim and no significant mass effect.
Hypertrophy of the right olivary nucleus with T2W and FLAIR hyperintense signal within.
Case Discussion
Hypertrophic olivary degeneration occurs after a loss of inhibitory synaptic input from afferent fibers, within the dentato-rubro-olivary tract, and represents deafferentation syndrome 1. Since the input fibers from the dentate nucleus are inhibitory (GABAergic), transneuronal degeneration results in enlargement rather than atrophy2.
Pontine cavernoma has typical MRI findings and generally shows a well-defined popcorn/reticulated appearance.