The impact of histopathology and NAB2–STAT6 fusion subtype in classification and grading of meningeal solitary fibrous tumor/hemangiopericytoma

• DOI: 10.1007/s00401-018-1952-6
• Publication Date: 2018-12-24T02:48:07Z
• Authors: Karen Fritchie; Kassandra Jensch; Evgeny A. Moskalev; Alissa Caron; Sarah Jenkins; Michael Link; Paul D. Brown; Fausto J. Rodriguez; Andrew Guajardo; Daniel Brat; José E. Velázquez...; Arie Perry; Ashley Wu; David R. Raleigh; Sandro Santagata; David N. Louis; Priscilla K. Bras...; Alexander Kaplan; Brian M. Alexander; Sabrina Rossi; Fabio Ferrarese; Florian Haller; Caterina Giannini
• Keywords: Hemangiopericytoma; Solitary Fibrous Tumor; Histopathology; Grading (engineering)

Meningeal solitary fibrous tumor (SFT)/hemangiopericytoma (HPC) is a rare with propensity for recurrence and metastasis. Although multiple classification schemes have been proposed, optimal risk stratification remains unclear, the prognostic impact of fusion status uncertain. We compared 2016 WHO CNS grading scheme (CNS-G), three-tier system based on histopathologic phenotype mitotic count, to 2013 soft-tissue counterpart (ST-G), two-tier count alone, in cohort 133 patients [59 female, 74 male; mean age 54 years (range 20-87)] meningeal SFT/HPC. Tumors were pathologically confirmed through review first resection (n = 97), local 35), or distant metastasis 1). A STAT6 immunostain showed nuclear expression 132 cases. NAB2-STAT6 was detected 99 111 successfully tested tumors (89%) including single immunonegative tumor. classified by CNS-G as grade 1 43), 2 41), 3 49), ST-G SFT 84) malignant 49). Necrosis present 16 cases (12%). On follow-up, 42 had at least one subsequent (7 only, 33 both). Twenty-nine died. univariate analysis, necrosis (p 0.002), 0.01), 0.004) associated recurrence-free (RFS) but not overall survival (OS). type significantly RFS OS, phenotype. modified incorporating higher correlation 0.0006) remained significant 0.02) when considering only primary tumors. From our data, rate appear stratify this family most accurately could be incorporated future scheme.