延髄原発melanocytomaの1例

Primary intramedullary melanocytoma of medulla oblongata:a case report

I．はじめに

　頸蓋内原発melanomaは比較的稀な疾患であり，その多くはmalignant melanomaである^13,16）．今回，われわれは延髄原発melanocytomaの1例を経験した．頭蓋内原発melanocytomaに関して渉猟した範囲では髄内に局在するmelanocytomaに関してはLimasらの1例を除き過去に報告は見られなかった^11,25）．また頭蓋内原発melanocytomaに関するMRI所見及び電顕的検索の報告も少ないので若干の考察を加えて報告する．

A case of intramedullary melanocytoma of the medulla oblongata, which has not been hitherto re-ported, is presented. The tumor ran on a slow progres-sive course. The patient died of pneumonia seven months after the operation. MRI findings did not spe-cify this tumor as they were not distinct from those of malignant melanoma. The tumor was totally black and was not attached to the dura. Microscopically, the neo-plastic cells were uniform in size and possessed abun-dant melanin granules in their cytoplasm. Mitosis was very rare. The ultrastructure of the tumor cells showed many melanosomes at varying stages of maturation.The melanocytoma in the eloquent region has an un-favorable outcome.