Case 17: Hypertrophic Olivary Degeneration Secondary to Pontine Hemorrhage

Bilateral hypertrophic olivary nucleus degeneration on magnetic resonance imaging in children with Leigh and Leigh-like syndrome

“…[3][4][5][6][7] A variety of insults can lead to hypertrophic olivary degeneration, of which the most commonly reported are haemorrhage, infarct, trauma, surgery or tumour. [8][9][10][11][12][13] The lesions result in loss of synaptic input to the inferior olivary nucleus and in trans-synaptic neuronal degeneration. 5 This has been considered a unique morphological form of trans-synaptic degeneration because it is associated with hypertrophy rather than atrophy of the affected structure.…”

“…14 Histopathologically, it is characterized by neuronal enlargement of the olivary neurons, neuronal loss, vacuolation, demyelination and marked astrogliosis. 3,5,7 It is most often unilateral when it is secondary to a structural lesion, although bilateral changes are recognized 8,15 and may occur if both the superior cerebellar peduncle and the central tegmental tracts are involved. 16,17 Bilateral hypertrophic olivary degeneration has been reported in a few metabolic, genetic, neurodegenerative and toxic disorders.…”

Hypertrophic Olivary Degeneration after Gamma-knife Radiosurgery for Pontine Metastasis

“…In addition to the location of the irradiatedˆeld, a signiˆcant clue to diagnosis will be a lack of contrast enhancement within the enlarged ION. 12 Because many kinds of malignant brain tumors demonstrate good contrast enhancement, Gd-enhanced T 1 -weighted imaging may be useful for distinguishing recurrent tumors from HOD.…”

Palatal Myoclonus (syn. Palatal Tremor)

“…In all pathologically studied cases of symptomatic PM it has involved the dentate nuclei of the cerebellum, the central tegmental tract, and the inferior olivary nucleus [18] on the opposite side. The inferior olivary nucleus shows marked hypertrophy [19, 20], usually after a delay of 1–6 months; palatal tremor may appear within days or after a delay of up to 30 months after an acute vascular lesion [21]. However, there are recorded instances of comparable olivary hypertrophy not accompanied by PM [21].…”