Precision in the verge: endoscopic submucosal dissection of squamous papilloma of the anal canal
Bibliographic record
Abstract
A 60-year-old female with a history of thyroid cancer, atrial fibrillation, and hypothyroidism was referred for further evaluation of a 1-cm rectal polyp identified during surveillance colonoscopy. The patient had no related symptoms or history of gastrointestinal malignancy. On endoscopic examination, the lesion (Figure 1A–C) was visualized at the anal verge arising from squamous mucosa. It exhibited papillary morphology characteristic of anal squamous papilloma. On magnification, prominent dilated intrapapillary capillary loops were visualized (Figure 1D). The decision was made to perform endoscopic submucosal dissection (ESD) for definitive diagnosis and treatment. Submucosal injection elevated the lesion and hybrid-snare tip ESD was employed to carefully resect the lesion en bloc. Histopathology revealed papillomatous squamous lesion with moderate squamous dysplasia (Figure 1E). Follow-up endoscopy at 6 months revealed no residual lesion or re-emergence (Figure 1F). Anal squamous papilloma resected via ESD: (A) White light of papillomatous lesion at anal verge; (B) linked-colour imaging; (C) blue light imaging; (D) BLI with magnification highlighting the vascular structure (E) Hematoxylin phloxine saffron stain: histology showing moderate squamous dysplasia and fibrovascular cores; (F) post-ESD 6-month follow-up image. Squamous papillomas of the anal canal are squamous epithelial neoplasms most commonly associated with human papillomavirus (HPV) infection.1 Although the lesions remain benign in the majority of cases, the potential for progression and malignant transformation (particularly in HPV subtypes 16 and 18) may warrant close endoscopic evaluation and management.2 ESD continues to emerge as an effective and safe modality to resect lesions in an array of locations in the gastrointestinal tract, including the anal canal.3,4 Through precise en bloc resection, it offers advantages in histopathological evaluation, ensuring clearer margins compared to fragmented resections. With appropriate training and case-by-case judgment, ESD may represent a reasonable resection option for suspicious premalignant and early malignant lesions in the anorectum. S.Y.-A.: wrote manuscript; D.H.: pathology image, editing manuscript; R.B.: project supervisor, endoscopic images, editing manuscript. None declared. R.B. is a consultant for Medtronic, Olympus, Pentax, Vantage, and Pendopharm. Conflict of interest disclosure forms (ICMJE) have been collected for all co-authors and can be accessed as supplementary material here. No new data were generated or analyzed in support of this research.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.002 | 0.002 |
| Insufficient payload (model declined to judge) | 0.001 | 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 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".