Abstract
BackgroundPrimary central nervous system (CNS) solitary fibrous tumour/hemangiopericytoma (SFT/HPC) is a rare neoplasm and its classification criteria have been redefined by the latest WHO Classification of CNS Tumours. Outcome can vary significantly among patients, thus reliable prognostic markers are warranted.MethodsPrimary CNS SFT/HPC diagnosed at the Pathology Unit of our Institution between 2006 and 2016 were retrospectively collected. Tumour grade along with immunohistochemistry for Ki67, STAT6, PHH3, CD34 and Bcl-2 were assessed. TERT promoter status was evaluated by Sanger sequencing.ResultsFifteen SFT/HPC were analysed: 9/15 (60%) female, median age at diagnosis 60 (range: 10–67). Six (40%) cases showed a SFT phenotype and mean H&E-mitotic count was 4.8/10 HPF. Tumour grade was I in 6, II in 4 and III in 5 cases. Mean PHH3-mitotic count was higher than H&E count (8.4 versus 4.8/10 HPF), but it would have determined a change in tumour grade in a sole case. Nuclear staining for STAT6 was present in 14/15 (93.3%). CD34 and Bcl-2 expression rates were lower in higher grade tumours. TERT promoter was mutated in two cases. Median follow up time was 2.4 years (6 months-7.4 years) and 5/15 (33%) patients developed local disease recurrence. Partial resection (p = 0.0185), higher WHO grade (p = 0.038), lower CD34 (p = 0.038) and Bcl-2 (p = 0.010) expressions were significantly associated with a poorer disease-free interval.ConclusionsWHO grade is the main prognostic tool in CNS SFT/HPC, but it could be integrated by other markers, like CD34 and Bcl-2, in the clinical practice. The relevance of TERT promoter mutations in this subset of CNS tumours needs further evaluation.
Highlights
Classification of primary central nervous system (CNS) solitary fibrous tumour/hemangiopericytoma (SFT/HPC) has been recently redefined by the latest World Health Organization (WHO) Classification of Tumours of the Central Nervous System (CNS)[1] by merging into a single category two previously separated diagnostic entities
Mean phosphorylated histone H3 (PHH3)-mitotic count was higher than H&E count (8.4 versus 4.8/10 high-power fields (HPF)), but it would have determined a change in tumour grade in a sole case
CD34 and B-cell lymphoma 2 (Bcl-2) expression rates were lower in higher grade tumours
Summary
Classification of primary CNS solitary fibrous tumour/hemangiopericytoma (SFT/HPC) has been recently redefined by the latest World Health Organization (WHO) Classification of Tumours of the Central Nervous System (CNS)[1] by merging into a single category two previously separated diagnostic entities (solitary fibrous tumour and hemangiopericytoma). This change mirrors what was already accepted for SFT/HPC of other sites (e.g. soft tissues and pleura) and is supported by a shared molecular hallmark: the chromosomal inversion at the 12q13 locus, fusing the NGFI-A-binding protein 2 (NAB2) and the signal transducer and activator of transcription 6 (STAT6) genes [2, 3]. Outcome can vary significantly among patients, reliable prognostic markers are warranted
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
