Skin-analogue primary poroid neoplasms of the head and neck with YAP1/WWTR1::MAML2/NUTM1 fusions: clinicopathologic and genetic spectrum of a novel tumor family delineated in a series of 10 cases
Bibliographic record
Abstract
Porocarcinoma is a rare type of aggressive skin adnexal carcinoma with terminal sweat duct differentiation, representing the malignant counterpart of the more common benign eccrine poroma. Diagnosis is based on distinctive morphology, supplemented by immunohistochemistry. While all tumors display a squamous immunophenotype, porocarcinomas only infrequently show frankly squamous cell cytology (squamous variant). Most poromas and porocarcinomas harbor YAP1::MAML2/NUTM1 or, rarely, WWTR1::NUTM1 fusions. We herein describe 10 extra-cutaneous primary (8 salivary, 1 mandibular, 1 nasopharyngeal) poroid neoplasms affecting 6 males and 4 females, aged 17 to 71 years (median, 49). The salivary cases originated in the parotid (n = 6; 1 within intraparotid lymph node), lower lip minor salivary glands (1), and palate (1). All, but one case, were treated by excision with or without lymph node dissection (two received adjuvant chemoradiation). Immune chemotherapy was given to the nasopharyngeal case. Histologically, five cases were frankly malignant (porocarcinoma-like), two infiltrating low-grade and three bland-looking (poroma-like). Three bland tumors were predominantly cystic. Regional lymph nodes were positive in three of three sampled cases. Limited follow-up was available for six patients (1-43 months; median, 6). Five patients were disease-free and one was alive with disease at 16 months. Targeted RNA sequencing revealed YAP1 fusions in nine cases (fused to MAML2 in four and to NUTM1 in five cases) and a WWTR1::NUTM1 fusion in one case. This series introduces skin-analogue poroid neoplasms as a distinct extra-cutaneous head and neck entity, originating mostly from major and minor salivary glands and recapitulating/spanning the spectrum of cutaneous poroid tumors with some cases showing bland poroma-like morphology, while others are high-grade porocarcinoma-like malignancies. This tumor type should be distinguished from the many primary and metastatic salivary neoplasms with squamous immunophenotype. In particular, the NUTM1-rearranged (NUTM1-immunopositive) cases should be distinguished from the more aggressive NUT carcinoma, as both share overlapping anatomic sites and squamous cell phenotype and express NUTM1. Moreover, MAML2-fused cases might be confused with variant or high-grade mucoepidermoid carcinomas, as they share squamous phenotype and MAML2 rearrangements. The biology of bland cases and their nosology (benign vs low-grade malignant) remain to be further characterized.
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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) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".