Olivary Hypertrophy in a Case with Palatal Myoclonus:Light‐ and Electron‐microscopic Study

Abstract

This is a report on the ultrastructural finding of the olivary hypertrophy in a case with palatal myoclonus. By light microscopy two types of neuronal changes were observed in the inferior olivary nucleus, i.e. the central chromatolysis and cytoplasmic vacuolation. Both types were also recognized by electron microscopy and the cytoplasmic vascuolation was identified as the vesiculated endoplasmic reticulum. In the reactive astrocytes, mitochondria were strikingly proliferated.

Hypertrophic olivary degeneration in children: four new cases and a review of the literature with an emphasis on the MRI findings

“…Pathological studies of HOD have demonstrated vacuolar degeneration, neuronal enlargement, astrocyte hypertrophy and gliosis [3]. Ultrastructural electron microscopic studies have shown that increased neuronal size could be attributed to neurofilamentous proliferation and cytoplasmic vacuolisation to the formation of rough endocytoplasmic reticulum vesicles [11]. A striking proliferation of mitochondria in the glial cells can be related to the increased metabolic activity shown by PET in the early stages of HOD [12].…”

Hypertrophic olivary degeneration and palatal myoclonus from a Streptococcus intermedius infection of the brain: illustrative case

“… 1 Histopathological and radiological studies have demonstrated neuronal enlargement in the setting of vacuolization of neurons with associated astrocytic hypertrophy and gliosis with astrocytic mitochondrial proliferation in the setting of hyperperfusion. 1 , 8 , 9 The natural history of the HOD includes initial degeneration of the olivary amiculum at 7 days followed by mild olivary enlargement, with neuronal hypertrophy at 3 weeks without glial reaction and subsequent hypertrophy of neurons and astrocytes at 8 months. 1 These neuropathological findings are concordant with radiological findings wherein the initial presentation of HOD was 1 month after the inciting lesion with T2 fluid-attenuated inversion recovery hyperintensity observed in the inferior olivary nucleus, followed by olivary hypertrophy at 6 months and resolution between 3 and 4 years.…”

“… 1 These neuropathological findings are concordant with radiological findings wherein the initial presentation of HOD was 1 month after the inciting lesion with T2 fluid-attenuated inversion recovery hyperintensity observed in the inferior olivary nucleus, followed by olivary hypertrophy at 6 months and resolution between 3 and 4 years. 9 , 10…”