Solitary fibrous tumor/hemangiopericytoma

Solitary fibrous tumor/hemangiopericytoma

Point

・NAB2-STAT6 fusionに伴うSTAT6の核内移行により，STAT6の免疫染色はSolitary fibrous tumor（SFT）/hemangiopericytoma（HPC）に高い感度を示し，両疾患の確定診断に使われる．

・Meningeal SFT/HPCは局所再発率や遠隔転移率が高く，再発・転移イベントは初回診断から10〜20年経過しても発生することが多い．

・組織所見における高いmitotic rateおよび壊死所見は予後不良の有意な因子である．NAB2-STAT6 fusion typeと予後には有意な関連はないが，高いmitotic rateやHPC phenotypeといった組織学的表現型には関連がある．

・局所コントロールにおいて，手術＋術後放射線治療が手術単独よりも予後を改善させるという報告が多い．一方で化学療法のエビデンスレベルは高くなく，主な薬剤としてはアントラサイクリン系薬剤が使用されている．

　Solitary fibrous tumor（SFT）/hemangiopericytoma（HPC）is a rare mesenchymal tumor with propensity for recurrence and metastasis. Although SFT and HPC were initially considered to be distinct entities, the identification of NAB2-STAT6 fusion as a definitive molecular alteration in both tumors has led to their integration into one disease entity, for both meningeal and non-meningeal lesions. This fusion leads to a nuclear relocation of the STAT6 protein and is detectable with immunohistochemistry. STAT6 immunohistochemistry has been shown to have excellent sensitivity and specificity for histological diagnosis. Although these discoveries have improved the diagnosis of SFT/HPC, the association of the NAB2-STAT6 fusion status with phenotype and prognosis remains unclear, and accurate prognostic factors have not been established. This comprehensive review provides current knowledge on the clinical, histological, and molecular characteristics of SFT/HPC.