高齢者の大脳半球に発生したpilocytic astrocytomaの1例

Pilocytic Astrocytoma of the Cerebrum Presenting in an Elderly Patient: A Case Report

Ⅰ．はじめに

　毛様性星細胞腫（pilocytic astrocytoma）は一般的には20歳以下の若年者に発症し，境界の明瞭な囊胞性腫瘤を形成する増殖の緩徐な星細胞系腫瘍である¹⁰⁾．小脳，視床下部，視神経などに好発し，大脳半球に発生することは稀である．今回われわれは，本腫瘍が高齢者の大脳半球に発症した極めて稀な1例を経験したので，文献的考察を加え報告する．

　We report a case of pilocytic astrocytoma of the cerebrum presenting in an elderly patient.

　A 76-year-old man was admitted to our department due to the development of dysarthria. MRI showed a cystic mass with an enhanced small mural nodule in the left frontal lobe. At surgery, the cyst contents were aspirated, and the mural nodule was excised. Histological examination showed a pattern that is usually seen in pilocytic astrocytoma of the cerebellum, including loose and compact areas composed of pilocytic and stellate cells, a few eosinophilic granular bodies, but not Rosenthal fibers.

　Pilocytic astrocytoma is a common type of pediatric brain tumor that can arise within either the cerebellum or the hypothalamic/chiasmatic region,but rarely seen in the cerebral hemisphere at an advanced age. To our knowledge,only 45 cases of pilocytic astrocytoma of the cerebrum developing in an adult are reported. In those cases,the symptoms of the disease developed during the third decade of life. The onset at a most advanced age as in the present case is thought to be extremely rare.