Myxoid glioneuronal tumor: Histopathologic, neuroradiologic, and molecular features in a single center series

Background: Myxoid glioneuronal tumor (MGT) is a benign glioneuronal neoplasm recently introduced in the World Health Organization (WHO) classification ot the central ne vous system (CNS) tumors. MGT. me typitally located in the septum pellucidum, foramen of :donro or periventricular white matter of the lateral ventricle. They were previously diagnosed as dysembryoplastic neuroepithelial tumors (DNT), showing histological features almost indistinguishable from classical cortical LNT. Despite that, MGTs have 'wen associated with a specific dinucleotide substitution at codon 385 in the platelet-derived growth factor receptor alpha (PDGFRA) gene, replacing a lysine residue with either leucine or isoleucine (p. LysK385Leu/lso). This genetic variation has never been descri iota ed in any other CN tumor. Wee-rims iota s and me hods: Thirty-one consecutive tumors previously diagnosed as DNTs at the Meyer Children's Hospital IRCCS between January 2010 and June 2021 were collected for a comprehensive study of their clinical, imaging, pathological features, and molecular profile. Resuls: In six out of the thirty-one tumors we had previously diagnosed as DNTs, we identified the recurrent dinucleotide mutation in the PDGFRA. All six tumors were typically located within the periventricular white matter of the lateral ventricle and in the septum pellucidum. We then renamed these lesions as MGT, according to the latest WHO CNS classification. In all patients we observed an indolent clinical course, without recurrence. t:onclusion: MGT represent a rare but distinct group of neoplasm with a typical molecular profiling, a characteristic localization, and a relative indolent clinical course.

Automated summary

The study introduces a benign tumor called Myxoid glioneuronal tumor (MGT), which has recently been included in the World Health Organization (WHO) classification of central nervous system (CNS) tumors. MGT is typically located in specific areas within the brain. The researchers identified a recurrent dinucleotide mutation in the PDGFRA gene in six out of 31 tumors previously diagnosed as DNTs, leading to the renaming of these tumors as MGT. Patients with MGT had an indolent clinical course without recurrence.