Cytomorphologic findings of cervical Pap smears from female-to-male transgender patients on testosterone therapy.

Background: The cervical cancer screening recommendation for transgender female-to-male (FTM) patients is the same as that for cisgender females. A lack of literature on testosterone-induced changes in cervical cytology in these patients may result in interpretation errors, especially without a proper clinical history. The aim of this study was to delineate the Papanicolaou (Pap) test findings in this patient population.

Methods: A pathology laboratory information system was used to obtain a cohort of FTM transgender patients on testosterone therapy (2009-2019). A cohort of age-matched, atrophic, control cisgender female patients (postpartum or menopausal) was selected. A retrospective review of the cytomorphologic findings on cervical Pap smears, pertinent follow-up, and human papillomavirus (HPV) test results was performed.

Results: Fourteen transgender patients (age range, 21-64 years; mean age, 42.5 years) receiving testosterone therapy with 17 Pap smears were identified. One of the 5 available HPV tests was positive for HPV, and 4 were negative. A Pap smear review revealed the following: negative for intraepithelial lesion (NILM; 82.4%), unsatisfactory (5.9%), atypical squamous cells of undetermined significance (ASCUS; 5.9%), and low-grade squamous intraepithelial lesion (5.9%). The Pap smears of the atrophic cisgender cohort (102 patients) revealed the following: NILM (92.5%), unsatisfactory (0.9%), ASCUS (5.6%), and high-grade squamous intraepithelial lesion (0.9%). The difference between the rates of epithelial cell abnormality in the 2 cohorts was not statistically significant. Although atrophy was noted in both groups, cytomorphologic findings of transitional cell metaplasia (TCM; 88.2%) and "small cells" (82.4%) were characteristic of the testosterone-treated transgender cohort. Histologic correlates of TCM and small cells were noted in hysterectomy specimens from 6 patients.

Conclusions: Small cells and TCM are common cytomorphologic findings in Pap smears of testosterone-treated transgender (FTM) patients. On the basis of histologic follow-up, small cells most likely represent atrophic parabasal cells of cervical-vaginal epithelium.