Andrew P Sciallis

Patterns of SATB2 and p16 reactivity aid in the distinction of atypical polypoid adenomyoma from myoinvasive endometrioid carcinoma and benign adenomyomatous polyp on endometrial sampling

AimsAtypical polypoid adenomyoma (APAM) is an uncommon uterine lesion composed of complex endometrioid glands with frequent squamous morular metaplasia and fibromuscular stroma. On endometrial curettage, biopsy or polypectomy specimens, the admixture of endometrioid glands and smooth muscle raises the differential diagnosis of myoinvasive endometrioid carcinoma. Reproductive‐age APAM patients may opt for fertility preservation, whereas myoinvasive carcinoma is treated surgically. One previous study reported an incidental finding that the stroma of APAM, in contrast to that of other polypoid lesions, was SATB2‐positive. APAM has also been reported to show increased stromal p16 staining. We aimed to assess whether SATB2 and p16 are useful stains for the distinction of APAM from myoinvasive carcinoma and benign adenomyomatous polyps.Methods and resultsCases of ‘atypical polypoid adenomyoma’ (n = 32), ‘adenomyomatous polyp’ (n = 39) and ‘myoinvasive endometrioid carcinoma’ (n = 30) were identified. Morphological features were assessed, along with the intensity and extent of SATB2 and p16 staining in the stromal component of each lesion. SATB2 expression was seen in the stromal components of 30 of 32 (94%) APAMs, versus none of 39 (0%) benign adenomyomatous polyps and five of 30 (17%) myoinvasive endometrioid carcinomas. Stromal p16 expression was seen in 31 of 31 (100%) APAMs, versus 20 of 39 (51%) benign adenomyomatous polyps and 12 of 30 (40%) myoinvasive endometrioid carcinomas.ConclusionsPatchy to diffuse SATB2 and block‐type p16 staining of fibromuscular stroma separating atypical endometrioid glands is more consistent with APAM than with myoinvasive endometrioid carcinoma. These stains are potentially useful adjuncts to careful morphological evaluation of endometrial biopsies/curettings.

Surface prostatic metaplasia, transitional cell metaplasia and superficial clusters of small basophilic cells in the uterine cervix: prevalence in gender‐affirming hysterectomies and comparison with benign hysterectomies from cisgender women

AimsAs gender‐affirming surgery is becoming more common, it is important for pathologists to recognize potential benign findings to avoid misinterpretation. Cervical transitional cell metaplasia and superficial clusters of small basophilic cells have been described in the context of gender‐affirming testosterone therapy; these findings may be misdiagnosed as high‐grade squamous intraepithelial lesions or endometrial cells on Pap smears. Prostatic metaplasia has been reported in the surface squamous epithelium of the vagina and the uterine cervix in individuals undergoing gender‐affirming androgen therapy; this finding is often associated with NKX3.1‐positive basal keratinocytes. The aim of this study was to assess the morphological and immunohistochemical features of the uterine cervix in gender‐affirming hysterectomies in comparison with benign hysterectomies from cisgender women.Methods and resultsWe assessed the morphological and immunohistochemical features of the uterine cervix in 49 gender‐affirming hysterectomies as compared with 57 hysterectomies from cisgender patients to establish the relative prevalences of surface prostatic metaplasia, NKX3.1‐positive basal keratinocytes, transitional cell metaplasia, and small basophilic cells in the cervical squamous epithelium. The cervical tissue from the gender‐affirming therapy cohort showed significantly higher prevalences of NKX3.1‐positive basal keratinocytes (86% versus 1.8%), transitional cell metaplasia (80% versus 3.5%), superficial clusters of small basophilic cells (67% versus 7%), and surface prostatic metaplasia (43% versus 3.5%).ConclusionNKX3.1‐positive basal keratinocytes, transitional cell metaplasia, small basophilic cells and surface prostatic metaplasia are all more prevalent in the cervices of individuals receiving gender‐affirming testosterone therapy; awareness of this fact allows pathologists to avoid the overdiagnosis of dysplasia or the recommendation of unnecessary follow‐up procedures.