Sacral Nerve Hemangiopericytoma: A Rare Case and Review of the Literature
Bibliographic record
Abstract
Introduction: Hemangiopericytomas usually occur in the soft tissue and skeletal system. They rarely present in the spinal canal as a primary tumor. There are several case reports describing primary spinal hemangiopericytomas of the cervical and thoracic spine; however, there are only 3 reports of sacral hemangioperictyomas (Liu, 2013; McMaster, 1975; Zhao, 2007). We report an extremely rare presentation of a primary spinal hemangiopericytoma arising from the S2 nerve root with local bony destruction of the sacrum. Case Report: A 52 year-old male presented with low back pain and left lower extremity numbness and tingling. MRI showed a 5.2 cm x 5.7 cm sacral mass, and CT showed local bony destruction of the sacrum. He complained of left S2 pain. The patient was taken for resection of the tumor. A gross total resection was achieved from a posterior midline approach. A corridor lateral to the sacral nerves allows resection of the ventral portion of the tumor. A gross total resection was achieved with a small residual adherent to the left S2 nerve root. Pathology confirmed the tumor to be a grade II hemangiopericytoma. Adjuvant radiotherapy was recommended due to the residual.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
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 teacher head, 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".