Primary Meningeal Pleomorphic Xanthoastrocytoma With Anaplastic Features: A Report of 2 Cases, One With BRAF(V600E) Mutation and Clinical Response to the BRAF Inhibitor Dabrafenib.
Primary meningeal gliomas are rare tumors composed of a heterogeneous group of neoplasms. We present 2 clinically aggressive cases of primary meningeal pleomorphic xanthoastrocytoma that clinically mimicked meningioma. One case presented in the posterior fossa of a 56-year-old woman; the other centered on the left operculum of a 35-year-old woman. These cases showed many of the classic features of pleomorphic xanthoastrocytoma, except that xanthomatous cells were rare and eosinophilic granular bodies were inconspicuous. Both cases exhibited high proliferative indices and superficially invaded the brain. One case harboring a BRAF mutation disseminated to the thecal sac and showed a clinical response to the targeted BRAF inhibitor dabrafenib. These cases seem to represent an unusual primarily extra-axial presentation of pleomorphic xanthoastrocytoma and may account for at least some of the previously reported cases of primary meningeal glioma and/or glial fibrillary acidic protein-immunoreactive meningioma variants. We suggest that BRAF mutation analysis be considered in all meningeal lesions showing atypical histologic or immunohistochemical profiles, particularly those exhibiting glial differentiation, as a diagnostic aid and possible indication for targeted therapy.
From the Departments of Pathology (AU, CRP, CAK, WZ, NLL), Anatomy (CRP), Neurosurgery (KH, MA), and Neuroscience (NLL), and Division of Neuro-oncology (VKP), The Ohio State University; and Department of Pathology and Laboratory Medicine, Nationwide Children's Hospital (CRP), Columbus Ohio; and Departments of Pathology (ONK, TGM, NLL) and Neurosurgery (JR), Henry Ford Hospital, Detroit, Michigan.
Aisulu
A
Usubalieva
Christopher R
CR
Pierson
Christina A
CA
Kavran
Kristin
K
Huntoon
Oleksandr N
ON
Kryvenko
Theodore G
TG
Mayer
Weiqiang
W
Zhao
Jack
J
Rock
Mario
M
Ammirati
Vinay K
VK
Puduvalli
Norman L
NL
Lehman
D000328:Adult; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D001254:Astrocytoma / Q000188:drug therapy / Q000235:genetics / Q000473:pathology*; D005260:Female; D006801:Humans; D007093:Imidazoles / Q000627:therapeutic use*; D007150:Immunohistochemistry; D008577:Meningeal Neoplasms / Q000188:drug therapy / Q000235:genetics / Q000473:pathology*; D008875:Middle Aged; D009154:Mutation; D010091:Oximes / Q000627:therapeutic use*; D048493:Proto-Oncogene Proteins B-raf / Q000235:genetics*
D000970:Antineoplastic Agents; D007093:Imidazoles; D010091:Oximes; C482119:BRAF protein, human; D048493:Proto-Oncogene Proteins B-raf; C561627:dabrafenib