Brainstem Radionecrosis in a Patient with Nasopharyngeal Carcinoma
Bibliographic record
Abstract
A 28-year-old female was admitted with a progressive gait disturbance, difficulty in swallowing, diplopia, and dysphonia.The neurological examination showed severe spastic paraparesis, pyramidal signs on the upper limbs, hoarseness, paresis of the left VI and VII, and bilateral impairment of all the lower cranial nerves.During examination of her medical history, she reported diabetes as well as nasopharyngeal carcinoma, for which she had undergone radiotherapy 1.5 years ago.She received a total dose of 63 Gy in 2-Gy fractions in three phases, which lasted for a period of 7 weeks.MRI revealed an extended lesion to the brainstem from midbrain to the medulla oblongata, which was shown to be hypointense on T1 and hyperintense on T2.This lesion presented a marked homogenous enhancement (Figure 1).The results of her standard biochemical examination were found normal.She was treated with 1 gr of methylprednizolone for 5 days, followed by gradual reduction of the dose.After 2 months of corticosteroid treatment, a mild clinical improvement was observed Cerebral radionecrosis is one of the late complications of radiation therapy for head and neck tumors.Severe clinical deterioration is characteristic, which in some cases may have a fatal outcome.The exact prevalence of radionecrosis is rather unknown, although an incidence rate of 5-35% has been reported in patients treated for intracranial tumors.For patients receiving a total dose of 55 Gy, the incidence rate varies between 3 and 5%.Generally, it is observed 6 months to 2 years after completion of the radiation therapy, and it mainly affects the cerebral white matter.The most commonly affected parts of the brain are the cerebral hemispheres, with a predilection for the temporal lobes and the cerebellum, whereas the brainstem is a rather rare site of involvement.Brainstem lesions include a wide range of differential diagnoses.Based on our patient's imaging, we should take into consideration tumor recurrence, vascular diseases (e.g., stroke, vascular malformations), osmotic demyelination syndrome, infectious rhomboencephalitis associated with Listeria monocytogenes, Bickerstaff brainstem encephalitis, or even primary brainstem gliomas.In the case of our patient, the final diagnosis was based on the clinical and imaging findings and the previous history of radiotherapy, after excluding all other possible diagnoses.Normal serum sodium levels and negative Listeria antibodies excluded the possibility of osmotic demyelination syndrome and rhomboencephalitis, respectively.Bickerstaff brainstem encephalitis was rather unlikely due to the lack of headache, drowsiness, and flaccid paralysis, which are key features in its clinical presentation.Considering the previous history of radiotherapy, radionecrosis was the most possible scenario.Radiation necrosis can also produce variable and nonspecific clinical symptoms associated with a mass
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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 | 0.004 |
| Meta-epidemiology (narrow) | 0.002 | 0.001 |
| Meta-epidemiology (broad) | 0.002 | 0.001 |
| Bibliometrics | 0.003 | 0.003 |
| Science and technology studies | 0.003 | 0.002 |
| Scholarly communication | 0.001 | 0.002 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.005 | 0.004 |
| 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".