Solitary Fibrous Tumors and Hemangiopericytomas of the Meninges: Overlapping Pathological Features and Common Prognostic Factors Suggest the Same Spectrum of Tumors

Abstract

Meningeal solitary fibrous tumors (SFTs) and hemangiopericytomas (HPCs) are distinct entities in the World Health Organization (WHO) classification of central nervous system (CNS) tumors while they belong to the same spectrum of tumors in other locations. Well-defined histological prognostic factors are also lacking for these tumors. In order to clarify the relationship between SFT and HPC and to find histological and immunohistochemical prognostic factors, we carried out a retrospective study in 89 patients. The following histological parameters were recorded: hypercellularity, collagenic areas, cytonuclear atypias, necrosis, mitotic count per 10 high-power fields, vasculo-nervous adherences defined by engulfment of vessel or nerve by the tumor, brain infiltration. We found overlapping histological and immunohistochemical features between SFT and HPC. The most relevant histological prognostic factors in the whole cohort for both progression-free survival (PFS) and overall survival (OS) in univariate analysis were hypercellularity, high mitotic count (>5 per 10 high-power fields) and necrosis. On the basis of these results, we propose a new grading scheme for these tumors which was of pronostic value for both PFS and OS in uni- and multivariate analysis. As extent of surgery was also a prognostic factor for both PFS and OS in univariate analysis, we propose that management of SFT/HPC might be based both on quality of removal and histological grade.

Clinicopathological differences between variants of the NAB2–STAT6 fusion gene in solitary fibrous tumors of the meninges and extra-central nervous system

“…Bouvier et al proposed a new grading scheme of meningeal SFT/HPC with three grades using three pathological features; cellularity, mitotic count (5 or more mitoses per 10 high-power fields), and necrosis, which correlated with prognosis [8]. Figure 1a-e shows representative cases of the histology of SFT/HPC with each grade.…”

Intramedullary Solitary Fibrous Tumor—A Benign Form of Hemangiopericytoma? Case Report and Review of the Literature

“…Nevertheless, recurrence is known and malignant behavior of SFT involving the central nervous system has been reported in a few cases (5,6,8,11,13,14,30,31,38,39).…”

“…Although there are some recurrent cases even after complete resection (3,4,11,21,27,38), SFTs of the central nervous system are principally benign tumors that can be treated by surgery alone, as they seem to be insensitive to chemotherapy or radiotherapy (5,6,28,31). However, the histological findings of SFT show many similarities to the more malignant hemangiopericytoma (HPC), which is also rare in the central nervous system (5,10,36,38).…”

“…However, the histological findings of SFT show many similarities to the more malignant hemangiopericytoma (HPC), which is also rare in the central nervous system (5,10,36,38). In the past decade more and more pathologists assume a common spectrum of these tumors (5,28).…”

Role of Pathologist in Driver of Treatment of CNS Tumors

“…It is very difficult to establish a panel series comprising each possibility in this topic. The panels which may be used according to localization have been provided below only as recommendation [26][27][28].…”