Metachronous Brain Tumors: Supratentorial Ependymoma Following Polymorphous Low-Grade Neuroepithelial Tumor of the Young
Bibliographic record
Abstract
A previously healthy 41-year-old man with a first generalized tonic-clonic seizure underwent a head CT that disclosed a peripherally located, partially calcified mass in the right frontal lobe (Fig. 1a).Neurological examination was unremarkable.MRI showed a T1-mixed intensity and T2-hyperintense mass with central cystic changes, mild heterogeneous enhancement, no significant perilesional edema and no restricted diffusion (Fig. 1b-f).Gross total resection and pathological examination confirmed a polymorphous low-grade neuroepithelial tumor of the young (PLNTY).Postoperative seizures were well-controlled on antiepileptic drugs, and there was no evidence of recurrence on MR surveillance.However, 11-months post-resection, he presented with worsening headaches and right facial weakness.Repeat MRI revealed a new T1-hypointense and T2-hyperintense heterogeneously enhancing mass in the left frontal centrum semiovale with different MR imaging characteristics from the original tumor, including mild restricted diffusion, internal necrosis and minimal edema (Fig. 2a-e).MR spectroscopy demonstrated increased choline and decreased NAA peaks within the lesion (Fig. 2f) suggesting high cellular turnover.Biopsy confirmed a ZFTA::RELA fusion-positive anaplastic ependymoma.Despite receiving radiation treatment and two resections, the patient ultimately passed away.PLNTY is a rare tumor first described in 2017 that frequently presents with seizures and refractory epilepsy.1 While most common in pediatric populations, cases have been reported in adults. 2 Imaging findings include intralesional calcifications, cystic components and well-defined margins.MRI signal characteristics include T1-iso/hypointensity and T2-iso/hyperintensity, mild heterogeneous enhancement, minimal perilesional edema and no diffusion restriction. 3The differential diagnosis includes oligodendroglioma due to imaging similarities and calcification, and ganglioglioma due to its epileptogenic nature.2,4 Histopathology and molecular analysis are required to diagnose PLNTY, with characteristic CD34 immunoreactivity and distinct genetic mutations.5
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.004 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".