6年間の経過観察中に腫瘍径の増大したDysembryoplastic Neuroepithelial Tumorの1例

An Enlarging Dysembryoplastic Neuroepithelial Tumor during a 6-year period : a case report

I．はじめに

　若年者の難治性てんかんで画像上cystic lesionを示す疾患には，くも膜嚢胞，脳梗塞，poren-cephalyなどの非腫瘍性病変とlow-grade glioma，ganglioglioma，dysembryoplastic neuroepithelialtumor（DNT）などの腫瘍性病変がある^{2,7,9,13,15）}．一方，CT又はMRIのみの情報では必ずしもこれらの病変の鑑別が容易でない場合もある^7,10,11）．今回われわれは当初くも膜嚢胞および脳梗塞と診断され，6年の経過で腫瘍径の増大したDNTの1症例を経験したので報告する．

A 16-year-old boy who had been found at the age of 9 years to have complex partial seizures was refer-red to our department by a psychiatrist for evaluation for surgical treatment of epilepsy, in 1994. A diagno-sis of multiple cerebral infarction accompanied with arachnoid cyst was made when he was 11 years old,in 1988, by computed tomography (CT) and magnetic resonance imaging (MRI) findings. Results of aneurological examination on admission revealed marked mental and speech retardation. MRI and CT stu-dies demonstrated an enlarged Sylvian fissure and a mass lesion in the left frontal lobe which was en-larged, compared to the findings of MRI in 1988. A left fronto-temporal craniotomy with excision of thefrontal lesion was performed. I listological examination revealed cortical dysplasia, multi-nodular pattern,and glioneuronal components, whose findings coincide with criteria for diagnosing dysembryoplasticneuroepithelial tumors. MIBI antibody immunostaining study revealed no positivity, but immunostainingstudy for PCNA (proliferation of cell nuclear antigen) revealed from 0 to 6.5% positivity in each nodule.PCNA high positivity was observed in the nodules which were composed of packed oligodendrocyte-likecells. Enlargement in the size of the lesion in our case suggests increased cell proliferation activity during a6-year period.