CS-10 POLYMORPHOUS LOW-GRADE NEUROEPITHELIAL TUMOR OF THE YOUNG: OUR CASE AND REVIEW OF THE LITERATURE


 Polymorphous low-grade neuroepithelial tumor of the young (PLNTY) is a new tumor that was officially listed in the WHO 5th edition in 2021. It is clinically and pathologically oligodendroglioma-like, but can be distinguished by CD34 positivity. Although this case was initially thought to be an oligodendroglioma-like low grade glioma, it was clinically and pathologically considered to be a typical case, so we report it here.14 year old female. No special notes, including growth and development. The patient suddenly developed a generalized tonic convulsion and was taken to the emergency room. A CT scan revealed a lesion with strong calcification in her left temporal lobe, and she was referred to our department. She had no neurological findings and underwent total resection under awake surgery. She was difficult to diagnose with intraoperative frozen section. diagnosis.The pathological findings are medium-sized oval to oblong nuclei, diffuse proliferation of tumor cells with delicate cell projections, and oligodendroglioma-like areas with perinuclear halos. A very large number of fine calcifications are observed, but necrosis and microvascular hyperplasia are not observed. GFAP, olig2, and nestin were positive, and synaptophysin, Nf, Hu C/D, MAP2, and chromograninA were negative. MIB-1 was less than 5%. The sequence was IDH1/2, TERTwild, and the BRAF-V600E mutation was recognized. Tumor cells were CD34-positive, leading to a final diagnosis of PLNTY. PLNTY is a new concept of tumor and accumulation is still small. Although this case has typical clinical and pathological features, preoperative diagnosis was difficult because it is a rare tumor. Intraoperative diagnosis is also difficult, suggesting the difficulty of diagnosing this tumor. Based on past cases, we report preoperative diagnostic imaging, intraoperative findings, and histopathological findings, including literature considerations.