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Background: Myxoid glioneuronal tumor (MGT) is a benign glioneuronal neoplasm recently introduced in the World Health Organization (WHO) classification of the central nervous system (CNS) tumors. MGTs are typically located in the septum pellucidum, foramen of Monro 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 DNT. Despite that, MGTs have been 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/Iso). This genetic variation has never been described in any other CNS tumor. Materials and methods: 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. Results: 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. Conclusion: MGT represent a rare but distinct group of neoplasm with a typical molecular profiling, a characteristic localization, and a relative indolent clinical course.

Platelet activating factor (PAF) is a lipid mediator of inflammation released by a variety of stimulated inflammatory cells. It may be involved in immune glomerulonephritis. Thus, its measurement in urine could give information on the mechanism of this disease. We present here a method to measure PAF in mouse urine, using gas-liquid chromatography-mass spectrometry (GLC-MS) in the selected ion recording (SIR) mode. Before instrumental analysis, the extracted and purified samples were hydrolyzed and derivatized with pentafluorobenzoyl chloride. Different experimental conditions are presented and discussed to corroborate the analytical findings. PAF levels in mouse urine were 2.08 +/- 0.46 ng/24 h. This procedure might represent a new experimental tool to establish the possible role of PAF as mediator of tissue damage in renal disease.