Hypertrophic Olivary Degeneration and Holmes' Tremor Secondary to Bleeding of Cavernous Malformation in the Midbrain
Background: Hypertrophic olivary degeneration (HOD) is a rare phenomenon, probably related to transsynaptic degeneration of the inferior olivary nucleus. It usually occurs as a response to primary injury of dento‐rubro‐olivary pathways.
Case report: A young man developed Holmes' tremor 7 months after a cavernous malformation bleed in the midbrain. Typical findings of HOD were observed in the magnetic resonance images: bilateral and asymmetric hypertrophy of the olivary nucleus with slight hypersignal in T2‐weighted images. Because of the striking disability related to drug‐resistant tremor, the patient underwent stereotactic thalamotomy (nucleus ventralis intermedius of the thalamus/zona incerta) with pronounced functional improvement over time.
Discussion: Disruption of circuits in the Guillain–Mollaret triangle classically results in palatal myoclonus, however midbrain (Holmes') tremor can also occur, as we now describe.