急速に囊胞が拡大して出血発症した成人Astroblastomaの1例

Astroblastoma with Rapid Cyst Expansion and Hemorrhage in an Adult: A Case Report

Astroblastomaは小児から若年成人を中心に全年齢層に発症する稀な原発性脳腫瘍で，その自然経過は不明である。手術摘出が重要で，それ以外の治療法は確立されていない。今回，偶然に小さな腫瘍として発見され，3カ月後に囊胞増大と出血により意識障害をきたした症例を経験した。手術にて肉眼的に全摘出し，BRAF^V600Eの陽性を確認した。低悪性度の診断で経過観察の方針としたが，1年後に局所再発して再手術，高悪性度の診断で放射線治療を施行した。分子遺伝学的な視点を含め文献的考察を加え報告する。

Abstract

Astroblastoma is an extremely rare primary brain tumor accounting for 0.45 to 2.8% of all neuroglial tumors and usually occurs in pediatrics and young adults. The natural history of astroblastoma still remains unknown. In the World Health Organization (WHO) classification of tumors of the central nervous system, astroblastoma is classified as other neuroepithelial tumors and standard treatment other than surgery has not been established. As molecular and genetic diagnosis becomes more important in the latest WHO classification of brain tumors, the development of therapeutic options based on the information of molecular genetics are expected. Here we report a case of astroblastoma in a 49-year-old male. Small tumor was discovered by coincidence during his check-up following traffic accident, but three months later, tumor bleeding with cystic enlargement resulted in disturbance of consciousness. Initial diagnosis of low grade astroblastoma with BRAF^V600E mutation was made. After 1 year, local tumor recurrence was observed. The histological diagnosis at recurrence was high grade astroblastoma. We here, discuss about diagnosis, treatment and the possibility of usefulness of molecular genetic analysis for astroblastoma with some literature review.

(Received 10 August, 2021; Accepted 15 December, 2021; Published 1 April, 2022)