第3脳室後半部に発生した乳児脈絡叢乳頭腫の1例

Choroid Plexus Papilloma in the Posterior Third Ventricle in Infancy : a case report

I．はじめに

　脈絡叢乳頭腫は全脳腫瘍の約0.5％^14）を占める比較的稀な腫瘍である．また乳児においてはほとんどが側脳室に発生し，第3脳室に発生するものはきわめて稀である．

　本稿では生後4カ月に健康診断で発見され，全摘出術を施行した第3脳室後半部脈絡叢乳頭腫の乳児例を報告し，そのmagnetic resonance image（MRI）上の特徴を述べ考察する．

Choroid plexus papillomas represent approximately 0.5% of all intracranial tumors, but they are found inthe third ventricle only infrequently. We report a case of choroid plexus papilloma in the third ventriclewhich is difficult to differentiate from a pineal region tumor. A 4-month-old female presented with bulgingfontanelle and sunset phenomenon. A CT scan and MRI showed marked hydrocephalus caused by a tumorextending from the posterior third ventricle to the peneal body. Preoperatively, we diagnosed the lesion asa pineoblastoma. The tumor was totally removed through the occipital transtentorial approach. Pathologic-al examination of the tumor revealed a typical choroid plexus papilloma. The operation was uneventful,and she has grown normally without reccurrence of the tumor for three years since the operation. A sagit-tal gadolinium-enhanced MRI was useful in our case to differentiate a choroid plexus papilloma from apineal region tumor, because the former extended into the aqueduct forming the shape of the letter Vwhile the latter compressed the aqueduct downward.