Extracranial invasion of a recurrent, transformed anaplastic pleomorphic xanthoastrocytoma: a case report
Bibliographic record
Abstract
Pleomorphic xanthoastrocytoma (PXA) is a rare tumour comprising <1% of all primary central nervous system tumours and the majority (~98%) occur supratentorially. We report on a 40-year-old female with a past medical history of a rare posterior fossa/cerebellar PXA who presented with a right-sided neck mass, decreased shoulder power and longstanding right tongue deviation with right-sided hemi-atrophy. The patient had prior tumour debulking. Recent MRI demonstrated an enhancing posterior fossa mass extending to the skull base at the jugular foramen and another mass in the upper neck along the jugular bulb with displacement and encasement of the right common carotid artery down to C5. Resection of the neck mass reveals an anaplastic PXA. The tumour has close approximation with adjacent peripheral nerves and is positive in 2 lymph nodes. Comparison with the original tumour molecular and immunohistochemical profiles reveals a conserved BRAF V600E mutation but the transformed malignant glioma now expresses dot-like EMA positivity and ATRX is completely lost (mutated). Transformation of a PXA (WHO Grade II) into an anaplastic PXA (WHO Grade III) has been well documented, but extracranial extension is extraordinarily rare. We report herein the first documented case of a posterior fossa PXA that underwent malignant transformation and extracranial invasion to the parapharyngeal space.
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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 | 0.003 |
| Meta-epidemiology (narrow) | 0.003 | 0.002 |
| Meta-epidemiology (broad) | 0.002 | 0.002 |
| Bibliometrics | 0.003 | 0.002 |
| Science and technology studies | 0.003 | 0.002 |
| Scholarly communication | 0.003 | 0.003 |
| Open science | 0.002 | 0.002 |
| Research integrity | 0.006 | 0.004 |
| Insufficient payload (model declined to judge) | 0.002 | 0.002 |
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".