原発性頭蓋内悪性黒色腫の1例

Primary Intracranial Melanoma: A case report

I．はじめに

　黒色腫はneural crest由来のmelanocyteを発生母地とする腫瘍である．melanocyteは皮膚や粘膜に多く存在するが，中枢神経系では脳軟膜や脳内血管鞘に存在しており，脳底部や脳表に発生することがあり得るが，その頻度は極めて稀である．最近著者らは，脳軟膜に原発したと考えられる悪性黒色腫の1例を経験したので，文献的考察を加え報告する．

A rare case of primary intracranial melanoma is pre-sented in a 34-year-old man with initial symptoms of per-sistent headache. In magnetic resonance imaging (MRI), this case had all the characteristic findings of intracranial melanoma which had been reported previously.

In ¹²³I-iodoamphetamine-single photon emission CT (¹²³I-IMP-SPECT), abnormal accumulation of ¹²³-IMP was recognized in early and late phase imaging, which was very specific to the lesion. This is the first report of ¹²³-IMP-SPECT performed on a primary intracranial melanoma. Tumor mass originated from pia mater was surgically resected, but the dissemination of tumor cells was recognized macroscopically. Pathological examina-tion of the specimen showed very little malignant changes of melanoma cells, which was in contrast to the previous reports. Although, no standard chemotherapy of the primary intracranial melanoma has been estab-lished, DAV therapy to the dissemination of tumor cells into the subarachnoid space, and intravenous administra-tion of interferon-13 were performed in this case. Methods of differential diagnosis and treatments of primary in-tracranial melanoma are reviewed and discussed.