Nephrogenic Adenoma: A Pitfall on Frozen Section of Urethral Strictures
Bibliographic record
Abstract
Urethral strictures are a common cause of urinary obstruction which can be treated with surgical resection. Frozen sections are rare and pose a diagnostic challenge to pathologists due to the presence of benign lesions such as nephrogenic adenoma. We retrospectively examined all specimens of urethral stricture resections submitted to pathology at our institution from 2012 to 2022 (n = 258). Final pathology reports were searched to identify patients with dysplasia, carcinoma, or nephrogenic adenoma. When available, frozen section reports were also examined and compared to the final report, and additional clinical history and microscopic images were collected for patients with nephrogenic adenoma. Nephrogenic adenoma was identified in 3.8% (10/258) of urethral stricture resections. Dysplasia was identified in one patient who underwent two separate resections, and squamous cell carcinoma was found in one resection. Intraoperative frozen section was requested in 3.4% of resections (9/258). In two resections, an initial diagnosis of squamous cell carcinoma was initially favoured, however when reviewed with a genitourinary pathologist the diagnosis was changed to "reactive process" with a final diagnosis of nephrogenic adenoma. Nephrogenic adenoma can be challenging on frozen section due to variable architectural patterns, inflammation, and reactive changes. While urethral strictures are relatively common, their assessment by frozen section is rare and pathologists may lack familiarity with the variable morphology of benign entities that can be seen on frozen section resulting in their misinterpretation. We highlight this potential diagnostic pitfall and demonstrate the value of a second opinion prior to definitive frozen section diagnosis of malignancy.
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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 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 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".