下オリーブ核の仮性肥大，2核神経細胞，白質膠症を伴うOlivo-ponto-cerebellar atrophyの1例

OLIVO-PONTO-CEREBELLAR ATROPHY WITH OLIVARY HYPERTROPHY, BINUCLEATED NEURONS AND FIBROUS GLIOSIS IN THE CEREBRAL WHITE MATTER

I．はじめに

　Olivo-ponto-cerebellar atrophy （以下OPCAと略す）の剖検例は決して稀ではないが，下オリーブ核の仮性肥大，豊富な2核神経細胞，強い白質膠症など特異な病変がみられ，生前，防腐剤のAF−2との関連が疑われた例を経験したので報告する。

A 55-year-old female developed ataxic gait and speech disturbance progressively. Attacks of un-consciousness which lasted about half an hour without convulsion were rarely noticed. Neuro-logical examination at 4 years after the onset ofthe illness, disclosed trunchal ataxia, explosive speech, ataxic movement of tongue, salivation, dysphagia, hyperactive tendon reflex in bilateral extremities and mental deterioration. She died of aspiration pneumonia 8 years after the onset of the disease.

Autopsy revealed grossly severe atrophy of the brain stem and cerebellum. Histologically, loss of nerve cells and glial proliferation in the pontine nucleus, degradation of the ponto-cerebellar fibers and loss of Purkinje cells with preservation of the granular layer and dentate nucleus were equivalent to olivo-ponto-cerebellar atrophy, though following peculiar features were combined.

At first, there was marked pseudohypertrophy of the bilateral olivary nuclei of the medulla. Micro-scopically, there were proliferation of bizarre astrocytes, vacuolation of neuronal perikarya and conglomerates of argentophilic fibers. As any localized lesion was not found in the dentato-olivary pathway, pathogenesis of this bilateral hypertrophyof the olive was not known. Such a hypertrophy has not been reported in OPCA.

Second peculiar finding of this case was existence of binucleated nerve cells in the pontine nucleus, thalamus and cerebellar cortex, where many ectopic Purkinje cells in the molecular layer had two nuclei. As bi- or multi-nucleated neurons were reported in many diseases acquired post-natally, pathogenesis of this change might belong to secondary reaction or fusion of neurons in the affected areas. Ectopic Purkinje cells in the molecular layer of the cerebel-lum have been interpreted as the result of"over migration"in the embryonal stage. Two nuclei in these ectopic Purkinje cells are therefore contro-versial concerning times of each occurence.

Third finding of the case was marked fibrous gliosis in the cerebral white matter. Cerebral changes in OPCA must be rightly evaluated, as the most of cerebro-fugal nerve fibers ends in the pontine nucleus.