Imaging features of polymorphous low-grade neuroepithelial tumors of the young: a case series

This study reports three cases of pediatric patients with polymorphous low-grade neuroepithelial tumor (PLNTY), confirmed by surgical pathology at our medical center, and presents their clinical and imaging features. PLNTY is a newly defined subtype in the 2021 WHO Classification of Tumors of the Central Nervous System (5th edition), categorized under pediatric-type diffuse low-grade glioma, WHO grade 1. The patients included one male and two females, aged 6, 9, and 9 years, respectively. The tumors were located in the thalamus, temporal lobe, and frontal lobe. All cases showed calcifications on CT scans. Magnetic resonance imaging (MRI) revealed low signal on T1-weighted images (T1WI) and high signal on T2-weighted images (T2WI), with localized enhancement after contrast administration. Diffusion-weighted imaging (DWI) demonstrated high signal in two cases and low signal in one case. Positron emission tomography-computed tomography (PET-CT) showed increased metabolic activity in two cases, raising suspicion of high-grade malignant brain tumors preoperatively. Postoperatively, none of the patients experienced tumor recurrence during follow-up periods ranging from 1 month to 6 years. This study highlights the clinical and imaging characteristics of PLNTY in pediatric patients and underscores the diagnostic challenges as well as the generally favorable postoperative prognosis.