巨大なcystの後頭蓋窩への進展を伴ったpineocytoma

Pineocytoma Associated with a Cyst:Report of a case

I．はじめに

　Pineocytomaは全国脳腫瘍統計^4）で全原発性脳腫瘍の0.2％を占める稀な腫瘍で，CT，MRIなどの画像診断所見の報告も少ない．われわれは後頭蓋窩へ延びる巨大な嚢胞を伴ったpineocytomaの稀な1例を経験したので，文献的考察を加えて報告する．

We report a case of pineocytoma associated with an unusually large cyst. A 15-year-old boy was admitted with a complaint of intermittent headache. Neurological examination was normal except for bilateral papil-ledema. CT scan showed triventricular hydrocephalus and a large mass. A solid portion of the tumor in the pineal and retrothalamic areas was isodense, and con-tained massive calcification on CT. A huge cystic por-tion extended far into the infratentorial, supracellebellar area. On MR, the solid tumor showed isointensity on TI-WI and iso-to high intensity on T2-WI, and was en-hanced by Gd-DTPA.

After a ventriculo-peritoneal shunt, the tumor was partially removed through an occipital supratentorial approach. Histological examination revealed a pineocy-toma with neuronal and astrocytic differentiations. Re-viewing the literature, it is most unusual to find a pineocytoma associated with a huge cyst as was seen in this case.