Desmoplastic infantile
astrocytoma/
ganglioglioma (
DIA/DIG) are rare primary glioneuronal
tumors that comprise 0.5% to 1.0% of all intracranial
tumors. While BRAF mutation is found in up to 50% of pediatric
gangliogliomas, data for
DIA/DIGs is limited. This study was carried out to evaluate the frequency of BRAF V600E mutation in
DIA/DIG. All cases of
DIA/DIGs diagnosed over 7 years (2010-2016) were reviewed retrospectively. The clinical, radiological and histopathological characteristics of these patients were evaluated along with immunohistochemical analysis for glial and neuronal markers. We evaluated presence of BRAF V600E mutation by Sanger sequencing and immunohistochemistry using
monoclonal antibody against clone VE1. Eight cases of desmoplastic infantile
astrocytoma/
ganglioglioma (6 DIGs and 2 DIAs) were evaluated. Four cases were of infantile type (age 10 months-2 years) and 4 cases of non-infantile type (age 10-14 years). BRAF VE1 immunohistochemistry (IHC) was positive in four cases (two DIG and two
DIA). All these four cases also showed heterozygous BRAF V600E mutation (T replaced by A at
nucleotide position 1799). Sequencing didn't detect BRAF mutation in any additional case. All four cases harboring this mutation were non-infantile (10-14 years). Cases with infantile presentation didn't carry this mutation. None of the cases showed recurrence on follow-up. Thus BRAF V600E mutation is common in desmoplastic non-infantile
astrocytoma/
ganglioglioma, but does not affect the prognosis. Identification of BRAF status opens the possibility of targeted
therapies for the subset of cases that clinically progress post-resection.