Some CNS sarcomas seen: A 22-year series.

Aims: Central nervous system (CNS) and spine are seldom impacted by primary or metastatic sarcomas. We reviewed our 22-year experience with metastatic versus primary mesenchymal sarcomas in adults versus pediatric patients, additionally asking how many might today undergo nomenclature changes using CNS World Health Organization, 5^th edition criteria.

Materials and methods: Case identification via text word search of pathology databases from our adult and pediatric referral hospitals, 2000 to August 2022, with exclusion of peripheral nervous system and primary chondro-osseous and notochordal tumors. Demographic, immunohistochemical, fluorescence in situ hybridization (FISH), and fusion results performed at the time of original diagnosis were acquired from reports.

Results: 57 cases were identified, with a 16 : 15 primary and 19 : 7 metastatic ratio in adult versus pediatric patients. Ewing sarcoma was the most frequent type (n = 18, 7 adult, 11 pediatric), with a rare primary PEComa, 2 alveolar soft part sarcomas, and metastatic angiosarcoma in the cohort. Only 3 cases, an intracranial sarcoma, DICER-1 mutant formerly diagnosed as rhabdomyosarcoma, an intracranial mesenchymal tumor, FET::CREB fusion-positive formerly diagnosed as angiomatoid fibrous histiocytoma, and a CIC-rearranged sarcoma required nomenclature updating by CNS WHO5 criteria.

Conclusions: Few primary or metastatic, adult or pediatric, CNS/spinal sarcomas required nomenclature updates; almost all had been satisfactorily classified at the time of diagnosis, using immunohistochemistry, FISH, or fusion results.