PATH-34. IT NEVER RAINS BUT IT POURS - DIAGNOSING ANAPLASTIC PLEOMORPHIC XANTHASTROCYTOMA TWICE IN A FORTNIGHT - OUR EXPERIENCE IN A RESOURCE CONSTRAINED SETTING
Bibliographic record
Abstract
Abstract Grade 3 Pleomorphic Xanthastrocytoma is a rare tumour (less than 1% of all astrocytic glial neoplasms). Present most commonly with seizures. Surgery and Radiation remain the mainstay of treatment with no clear role for traditional systemic chemotherapies; BRAF inhibitors show some benefit. We report two cases who were diagnosed within a month of each other - one was initially diagnosed in 2017- presented with altered smell, headache and diplopia. Found to have a well-defined lobulated heterogeneously enhancing suprasellar parasellar lesion. After Gross Total Resection, was diagnosed from various centers as Anaplastic Ependymoma WHO Grade III; Gllioblastoma WHO Grade IV; Anaplastic Pleomorphic Xanthastrocytoma WHO Grade III. Based on immunohistochemistry, was considered Anaplastic Ependymoma WHO Grade III. Spine screening was negative; received adjuvant Radiation 60Gy in 30 fractions. After a disease free interval of 6 years, developed a recurrence at the post op site. He underwent repeat decompression and the histopathology showed Grade 3 Pleomorphic Xanthastrocytoma. Immunohistochemistry- OLIG2: diffuse positive; R132H p.IDH1: negative; ATRX: intact nuclear expression; Mismatch repair proteins (MSH2, MSH6, MLH1, PMS2); intact nuclear expression; MIB-1 labelling index: 10-12%; H3 p.K27M: negative; GFAP: variable positivity; Podoplanin and p53 shows focal positivity; EMA, CD 34 are negative. He competed Reirradiation in January 2024. He is asymptomatic and on follow up. The second case -15 year old boy presented with episodes of absence seizures. Imaging showed a predominantly extraaxial lesion at tentorial apex. He underwent decompression and histopathology showed Grade 3 Pleomorphic Xanthastrocytoma. Immunohistochemistry - cells positive for S100 and variably positive for GFAP, OLIG2 and vimentin; ATRX: Retained expression, IDH1p.R132H, EMA, Synaptophysin, Neu N: Negative, p53: Focally positive, CD34: Positive in few tumour cells, Ki-67: 14-16 %.V600 mutation detected in the BRAF gene. Had Adjuvant RT 60 Gy in 30 fractions -completed in March 2024. MRI at 1 month - no significant change in overall tumour burden compared to post operative MRI. Was offered Dabrafenib with Trametinib.
Stored with the screening record, where it is evidence for the labels above.
How this classification was reachedexpand
The three-model screen
all 5,600 screened works →All three models called this out of scope.
Neuro-oncology case report of two brain tumor diagnoses.
This reports clinical case experiences involving a rare brain tumor, not research practice.
Clinical case reports of rare brain tumours and their diagnosis/treatment.
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 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.012 | 0.005 |
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".