脳ドックの指摘から14年後に手術に至った後期高齢者pilocytic astrocytomaの1例

An Elderly Patient with Pilocytic Astrocytoma Operated on 14 Years after Initial Detection:A Case Study

Ⅰ．はじめに

　毛様性星細胞腫（pilocytic astrocytoma：PA）は，小児から若年者の小脳半球に好発し，境界明瞭な囊胞性腫瘤を形成する星細胞系腫瘍である¹⁵⁾．今回，脳ドックで発見されたものの無症候性病変であったため経過観察となり，発見から約14年後に記銘力低下を来し，手術に至った後期高齢者PAの1例を経験したので報告する．

　Pilocytic astrocytomas are found predominantly in the pediatric population and are extremely rare in elderly patients. We describe a case of pilocytic astrocytoma in an elderly patient who presented with the symptoms of an enlarged tumoral cyst.

　A 70-year-old woman was found to have an asymptomatic small solid tumor with a cystic component in the right frontal lobe at “Ningen Dock（medical checkup）of the Brain”. She was hospitalized and underwent further examinations including cerebral angiography. At that time, she was opposed to undergoing an operation for tumor removal owing to lack of symptoms. Approximately fourteen years later, she presented with dizziness upon posture conversion and recent memory disturbance. Computed tomography scanning revealed an enlarged cyst in the frontal lobe and perifocal edematous changes. Gadolinium-enhanced magnetic resonance imaging partially revealed the solid tumor and cystic capsule. The solid tumor had not enlarged substantially. The cystic fluid was aspirated and the solid tumor was resected via a frontal transcortical approach. The histological diagnosis was pilocytic astrocytoma without malignant features. After surgery, the patient's symptoms improved and additional therapy was not provided. After a year of postoperative follow-up, the size of the cystic lesion has reduced, and no recurrence of the solid tumor has been observed.