Clinicopathological findings in female-to-male gender-affirming breast surgery

Effect of testosterone therapy on breast tissue composition and mammographic breast density in trans masculine individuals

BACKGROUND

The effect of gender-affirming testosterone therapy (TT) on breast cancer risk is unclear. This study investigated the association between TT and breast tissue composition and breast tissue density in trans masculine individuals (TMIs).

METHODS

Of the 444 TMIs who underwent chest-contouring surgeries between 2013 and 2019, breast tissue composition was assessed in 425 TMIs by the pathologists (categories of lobular atrophy and stromal composition) and using our automated deep-learning algorithm (% epithelium, % fibrous stroma, and % fat). Forty-two out of 444 TMIs had mammography prior to surgery and their breast tissue density was read by a radiologist. Mammography digital files, available for 25/42 TMIs, were analyzed using the LIBRA software to obtain percent density, absolute dense area, and absolute non-dense area. Linear regression was used to describe the associations between duration of TT use and breast tissue composition or breast tissue density measures, while adjusting for potential confounders. Analyses stratified by body mass index were also conducted.

RESULTS

Longer duration of TT use was associated with increasing degrees of lobular atrophy (p < 0.001) but not fibrous content (p = 0.82). Every 6 months of TT was associated with decreasing amounts of epithelium (exp(β) = 0.97, 95% CI 0.95,0.98, adj p = 0.005) and fibrous stroma (exp(β) = 0.99, 95% CI 0.98,1.00, adj p = 0.05), but not fat (exp(β) = 1.01, 95%CI 0.98,1.05, adj p = 0.39). The effect of TT on breast epithelium was attenuated in overweight/obese TMIs (exp(β) = 0.98, 95% CI 0.95,1.01, adj p = 0.14). When comparing TT users versus non-users, TT users had 28% less epithelium (exp(β) = 0.72, 95% CI 0.58,0.90, adj p = 0.003). There was no association between TT and radiologist's breast density assessment (p = 0.58) or LIBRA measurements (p > 0.05).

CONCLUSIONS

TT decreases breast epithelium, but this effect is attenuated in overweight/obese TMIs. TT has the potential to affect the breast cancer risk of TMIs. Further studies are warranted to elucidate the effect of TT on breast density and breast cancer risk.

The Impact of a Breast Cancer Risk Assessment on the Decision for Gender-Affirming Chest Masculinization Surgery in Transgender and Gender-Diverse Individuals: A Pilot Single-Arm Educational Intervention Trial

BACKGROUND

Persons assigned female or intersex at birth and identify as transgender and/or gender-diverse (TGD) may undergo gender-affirming chest masculinization surgery (GACMS); however, GACMS is not considered equivalent to risk-reducing mastectomies (RRM). This study aimed to estimate the prevalence of elevated breast cancer (BC) risk in TGD persons, compare self-perceived versus calculated risk, and determine how risk impacts the decision for GACMS versus RRM.

METHODS

A prospective single-arm pilot educational intervention trial was conducted in individuals assigned female or intersex at birth, age ≥ 18 years, considering GACMS, without a BC history or a known pathogenic variant. BC risk was calculated using the Tyrer-Cuzik (all) and Gail models (age ≥ 35 years). Elevated risk was defined as ≥ 17%.

RESULTS

Twenty-five (N = 25) participants were enrolled with a median age of 24.0 years (interquartile range, IQR 20.0-30.0 years). All were assigned female sex at birth, most (84%) were Non-Hispanic (NH)-White, 48% identified as transgender and 40% as nonbinary, and 52% had a first- and/or second-degree family member with BC. Thirteen (52%) had elevated risk (prevalence 95% confidence interval (CI) 31.3-72.2%). Median self-perceived risk was 12% versus 17.5% calculated risk (p = 0.60). Of the 13 with elevated risk, 5 (38.5%) underwent/are scheduled to undergo GACMS, 3 (23%) of whom underwent/are undergoing RRM.

CONCLUSIONS

Over half of the cohort had elevated risk, and most of those who moved forward with surgery chose to undergo RRM. A BC risk assessment should be performed for TGD persons considering GACMS. Future work is needed to examine BC incidence and collect patient-reported outcomes. Trial Registration Number ClinicalTrials.gov (No. NCT06239766).

Aspects to consider regarding breast cancer risk in trans men: A systematic review and risk management approach

BACKGROUND

The risk of breast cancer in trans men is currently a poorly understood subject and trans men likely carries a different level of risk from that of cis women.

AIM

This review aims to review several aspects that affects breast cancer risk in trans men and to apply the Swiss cheese model to highlight these risks. The study takes its cue from a systematic review of all described breast cancer cases in trans men following medical or surgical intervention because of gender dysphoria.

METHODS

PubMed was systematically searched on the 14th of March 2023 to find all published cases of breast cancer following chest contouring surgery in trans men. Included articles had to involve trans men, the diagnosis of breast cancer had to be preceded by either a medical or surgical intervention related to gender dysphoria, and cases needed to involve invasive breast cancer or ductal carcinoma in situ. Articles were excluded if gender identity in the case subject was unclear and/or a full English version of the report was unavailable. Quality and risk of bias was evaluated using the GRADE protocol. A literature review of specific risk altering aspects in this population followed. The Swiss cheese model was employed to present a risk analysis and to propose ways of managing this risk.

RESULTS

28 cases of breast cancer in trans men have been published. The Swiss cheese model identified several weaknesses associated with methods of preventing breast cancer in trans men.

CLINICAL IMPLICATIONS

This study may highlight the difficulties with managing risk factors concerning breast cancer in trans men to clinicians not encountering this patient group frequently.

CONCLUSION

This review finds that evidence for most aspects concerning breast cancer in trans men are inadequate, which supports the establishment of a risk-management approach to breast cancer in trans men.

Effect of testosterone therapy on breast tissue composition and mammographic breast density in trans masculine individuals

Objective

Determine the association between TT and breast tissue composition and breast tissue density in trans masculine individuals (TMIs).

Design

This is a cross-sectional study.

Setting

TMIs (n=444) underwent chest-contouring surgeries to treat their gender dysphoria between 2013 and 2019 at an urban medical center.

Participants

Of the 444 TMIs, 425 had pathology images analyzed by our deep-learning algorithm to extract breast tissue composition. A subset of 42/444 TMIs had mammography prior to surgery; mammography files were available for 25/42 TMIs and analyzed using a breast density software, LIBRA.

Main Outcomes and Measures

The first outcome was the association of duration of TT and breast tissue composition assessed by pathologists (categories of lobular atrophy and stromal composition) or by our algorithm (% epithelium, % fibrous stroma, and % fat). The second outcome is the association of TT and breast density as assessed by a radiologist (categorical variable) or by LIBRA (percent density, absolute dense area, and absolute non-dense area).

Results

Length of TT was associated with increasing degrees of lobular atrophy ( p <0.001) but not fibrous content ( p =0.821) when assessed by the pathologists. Every six months of TT was associated with decreased amounts of both epithelium (exp(β)=0.97, 95% CI 0.95-0.98, adj p =0.005) and stroma (exp(β)=0.99, 95% CI 0.98-1.00, adj p =0.051), but not fat (exp(β)=1.01, 95%CI 0.98-1.05, p =0.394) in fully adjusted models. There was no association between TT and radiologist's breast density assessment ( p =0.575) or LIBRA measurements ( p >0.05).

Conclusions

TT decreases breast epithelium and fibrous stroma, thus potentially reducing the breast cancer risk of TMIs. Further studies are warranted to elucidate the effect of TT on breast density and breast cancer risk.

Summary Box

Very little is known about the effect of gender-affirming testosterone therapy on cancer risks, such as breast cancer.Epidemiological studies had different conclusions about the association between testosterone and breast cancer in cisgender women (positive association) and trans masculine individuals (inverse association).More laboratory-based research are needed to understand the effect of testosterone on breast cancer risk in the understudied trans masculine population.Our study provides quantitative histological evidence to support prior epidemiological reports that testosterone may reduce breast cancer risk in trans masculine individuals.

Masculinizing hormone therapy effect on breast tissue: Changes in estrogen and androgen receptors in transgender female-to-male mastectomies

PURPOSE

Almost two percent of individuals in the United States identify as gender non-conforming. In the female-to-male (FTM) transgender population, masculinizing hormone therapy with testosterone is commonly prescribed in gender transition. To date, the effects of exogenous androgens on breast tissue and its roles in altering breast cancer risk are poorly understood. This study examines the histopathologic findings in gender affirming mastectomy (GAM) in transgender FTM patients and the effects of exogenous androgens on estrogen receptors (ER) and androgen receptors (AR).

METHODS

A retrospective review of pathology specimens obtained between 2017 and 2020 was performed comparing androgen exposed breast tissue with breast tissue without androgen exposure. Breast specimens were obtained from patients who underwent FTM GAM with recorded exogenous androgen exposure. Control breast specimens were obtained from reduction mammoplasty (RM) procedures in cisgender women which were aged matched to the GAM cohort, as well as postmenopausal women with benign/prophylactic mastectomy procedures; all controls were without androgen exposure. The histopathologic findings were assessed. Immunohistochemistry for AR and ER was performed and the score interpreted by digital image analysis.

RESULTS

Androgen-exposed breast tissue revealed dense fibrotic stroma, lobular atrophy, thickened lobular basement membranes, and gynecomastoid changes. Longer duration of androgen exposure resulted in a more pronounced effect. The incidence of atypia or cancer was lower in GAM than RM cohort. ER and AR expression was highest in transgender male breast tissue with intermediate duration of exogenous androgen exposure.

CONCLUSION

Increased androgen exposure is associated with lobular atrophy and gynecomastoid changes in breast parenchyma. Overall, ER and AR are expressed strongly in lobular epithelium in patients with prolonged androgen exposure. Exogenous testosterone does not appear to increase risk for breast cancer. Additional studies are needed to investigate the mechanism responsible for these changes at a cellular level and its role in cancer development.

Preoperative breast imaging and histopathological findings in chest contouring surgery on transmen

BACKGROUND

Chest contouring is the most common surgical procedure transmen receive. Only a few articles discuss the importance of preoperative imaging and postoperative histopathological analysis of excised breast tissue. We studied the findings of preoperative breast imaging and the results of postoperative histopathological analysis in a clinical setting.

MATERIALS AND METHODS

Data from 220 patients were collected retrospectively from 2005 to 2018. Preoperative imaging modalities and their findings were recorded and classified according to the American College of Radiology Breast Imaging Reporting and Data System. The histopathological findings in breast specimens were categorized based on the World Health Organization Classification of Breast Tumors (5th edition).

RESULTS

Preoperative imaging was performed in 133 (60.5%) patients. Patients in the ultrasound-only group were younger (mean age 22.8) than the other groups (mammogram (MGR) 37 years and MGR+US 35.5 years). Preoperative imaging results were normal in 131 (98.5%) patients. Two patients needed further evaluation. Histopathological results were available on 206 (93.6%) patients. The most common histopathological findings were fibrosis (67.5%), atrophy (34.3%), and chronic mastopathy (14.5%). There were no high-risk or malignant findings.

CONCLUSIONS

The need for further examinations based on routine preoperative imaging was low (1.5%). Therefore, more individualized patient selection for preoperative imaging is justified. There were no high-risk or malignant findings in histopathological analysis, and the occurrence of benign findings was similar to that reported in previous studies. Despite our findings, based on current knowledge, histopathological examination of excised breast tissue can still be recommended. Therefore, future studies are needed to define clear guidelines.

Caring for transgender populations: A primer for the dermatopathologist

With increasing access to electronic health records, patients may encounter dermatopathology reports more readily. Dermatopathologists should consider their impact and interactions with transgender patients, who may face specific health and healthcare inequities. Rendering accurate diagnosis for skin diseases requires accurate information about patient's sex assigned at birth and gender identity. Understanding how sex and gender identity data flow between electronic health records, laboratory information systems, insurance billing systems, and patients will be important to avoid patient misgendering, to render accurate diagnoses, to maintain consistency in dermatopathology reports, and to avoid insurance billing denials. Dermatopathologists have important roles to build patient trust in the healthcare system and to help dermatologists diagnose, treat, and characterize skin diseases in transgender populations.

The Impact of Exogenous Testosterone on Breast Cancer Risk in Transmasculine Individuals

BACKGROUND

Exogenous testosterone is vital to gender-affirming therapy for transmasculine individuals. Testosterone may be implicated in breast cancer (BCa) because it can activate androgen and estrogen receptors. To further explore this risk, we performed a systematic review to investigate the impact of exogenous testosterone on BCa risk in transmasculine individuals.

METHODS

We searched PubMed/MEDLINE and Ovid/Embase for clinical and preclinical studies assessing BCa and testosterone therapy and screened 6125 articles independently. We ascertained level of evidence using a modified tool from Cook et al (Chest. 1992;102:305S-311S) and risk of bias using a modified Joanna Briggs Institute's Critical Appraisal Tool.

RESULTS

Seventy-six studies were included. Epidemiological data suggested that BCa incidence was higher in transmasculine individuals compared with cisgender men but lower compared with cisgender women. Histological studies of transmasculine breast tissue samples also demonstrated a low incidence of precancerous lesions. Interestingly, cases demonstrated that BCa occurred at a younger average age in transmasculine individuals and was predominantly hormone receptor positive. The mechanism for BCa in transmasculine individuals may be related to androgen receptor stimulation or conversion to estradiol. Serum studies reported varied estradiol levels associated with exogenous testosterone. Animal and in vitro studies demonstrated that testosterone was growth inhibitory but may induce proliferation at higher doses or with low estradiol levels.

CONCLUSIONS

Plastic surgeons play a critical role in providing gender-affirming care for transmasculine patients. The limited studies available suggest that this patient population has decreased risk for BCa when compared with cisgender women; however, any BCa that does occur may have different clinical presentations and underlying mechanisms compared with cisgender women and men. Overall, the limitations for clinical studies and discrepancies among preclinical studies warrant further investigation.

Histopathologic Features of Breast Tissue From Transgender Men and Their Associations With Androgen Therapy

OBJECTIVES

To assess the histopathologic features of breast tissue of transgender men (TM) undergoing gender-affirming bilateral mastectomies in relation to androgen therapy (AT).

METHODS

We reviewed 374 transgender bilateral mastectomy cases from 2017 to 2020. Of these, 314 (84.4%) patients received preoperative AT. We compared these with 127 cases of cisgender females undergoing elective breast reduction.

RESULTS

Breast specimens from TM on AT, compared with cisgender women, showed a median higher gross percentage of fibrous tissue (P < .001), reduced lobular density (P = .004), higher amount of lobular atrophy (P < .001), and lower incidence of cysts (P < .001), apocrine metaplasia (P < .001), calcifications (P < .001), columnar cell change (P = .002), and atypia (P = .003). Each additional month of AT was associated with a 2% decrease in the odds of having nonapocrine cysts (P = .02), a 5% decrease in the odds of having usual ductal hyperplasia (P = .007), and a 0.14% decrease in median lobular density (95% confidence interval, -0.18 to -0.05).

CONCLUSIONS

In this study, breast specimens from TM, particularly with a history of AT, had a higher proportion of fibrous tissue, fewer lobules, and a higher degree of lobular atrophy than cisgender females. Rare cases of atypia were not predicted by preoperative imaging or gross findings, supporting routine microscopic evaluation of these specimens.

Current Practices in the Pathologic Assessment of Breast Tissue in Transmasculine Chest Surgery

BACKGROUND

No guidelines exist regarding management of breast tissue for transmasculine and gender-nonconforming individuals. This study aims to investigate the experiences and practices regarding perioperative breast cancer risk management among the American Society of Plastic Surgery (ASPS) surgeons performing chest masculinization surgery.

METHODS

An anonymous online 19 question survey was sent to 2517 US-based ASPS members in October 2019.

RESULTS

A total of 69 responses were analyzed. High volume surgeons were more likely from academic centers (OR 4.88 CI 1.67 - 15.22; p=0.005). Age ≥40 (85.5%, n=59) and family history of breast cancer in first-degree relatives (68.1%, n=47) or family with a diagnosis before age 40 (71.0%, n=49) were the most common indications for preoperative imaging. 27.5% (n=19) of the respondents routinely excise all macroscopic breast tissue, with 30.4% (n=21) routinely leaving breast tissue. 73.9% (n=51) of respondents routinely send specimens to pathology. There was no significant correlation between surgical volume or type of practice and odds of sending specimens to pathology. High patient costs and patient reluctance (39.1%, n=27, and 35.3%, n=24, respectively) were the most often cited barriers for sending specimens to pathology. 8.7% (n=6) of respondents have found malignant or premalignant lesions in masculinizing breast specimens.

CONCLUSION

Large variation was found among surgeons' perioperative management of chest masculinizing surgery patients regarding preoperative cancer screening, pathologic assessment of resected tissue, and postoperative cancer surveillance. Standardization of care and further studies are needed to document risk, incidence, and prevalence of breast cancer in the transmasculine population before and after surgery.

Reproductive Organ Pathology of Individuals Undergoing Gender-Affirming Surgery

As gender-affirming surgeries become more routine, it is increasingly important for pathologists to recognize the expected histologic changes seen in various tissues secondary to gender-affirming hormone therapy. For example, exogenous testosterone-related squamous atrophy or transitional cell metaplasia of the cervix may be confused for high-grade squamous intraepithelial lesion. In addition to distinguishing between benign and dysplastic/malignant features, pathologists should be mindful of the phrasing of their reports and aim to use objective, nongendered language.

Prostatic metaplasia and pilar differentiation in gender-affirming mastectomy specimens

With the increasing practice of gender-affirming mastectomy as a therapeutic procedure in the setting of gender dysphoria, there has come a profusion of literature on the pathologic findings within these specimens. Findings reported in over 1500 patients have not included either prostatic metaplasia or pilar metaplasia of breast epithelium. We encountered both of these findings in the course of routine surgical pathology practice and therefore aimed to analyze these index cases together with a retrospective cohort to determine the prevalence, anatomic distribution, pathologic features, and associated clinical findings of prostatic metaplasia and pilar metaplasia in the setting of gender-affirming mastectomy. In addition to the 2 index cases, 20 additional archival gender-affirming mastectomy specimens were studied. Before mastectomies, all but 1 patient received testosterone cypionate, 6/22 patients received norethindrone, and 21/22 practiced breast binding. Prostatic metaplasia, characterized by glandular proliferation along the basal layer of epithelium in breast ducts, and in one case, within lobules, was seen in 18/22 specimens; 4/22 showed pilar metaplasia, consisting of hair shafts located within breast ducts, associated with squamoid metaplasia resembling hair matriceal differentiation. By immunohistochemistry, prostatic metaplasia was positive for PSA in 16/20 cases and positive for NKX3.1 in 15/20 cases. Forty-three reduction mammoplasty control cases showed no pilar metaplasia and no definite prostatic metaplasia, with no PSA and NKX3.1 staining observed. We demonstrate that prostatic metaplasia and pilar metaplasia are strikingly common findings in specimens from female-assigned-at-birth transgender patients undergoing gender-affirming mastectomy. Awareness of these novel entities in the breast is important, to distinguish them from other breast epithelial proliferations and to facilitate accrual of follow-up data for better understanding their natural history.

Pathological Evaluation of Breast Specimens in Transgender Chest Masculinization: Incidental Findings and Effect of Prior Chest Binding and Androgen Therapy in 74 Consecutive Patients

Background: The rate of masculinizing chest surgery for gender affirmation continues to increase. With a paucity of literature on pathological evaluation of breast specimens in this patient population, there is a need for these data and for protocols on the handling of these specimens. Methods: A retrospective chart review was performed between 2015 and 2020 on all patients who underwent chest masculinization surgery for gender dysphoria by the senior author (J.D.K.). Inclusion criteria were any patient with sex assigned female at birth who underwent removal of breast and/or nipple areolar complex tissue for gender affirmation. Patient demographics were recorded. Bilateral breast tissue was sent for routine pathology in all cases and findings were recorded. A p-value of <0.05 was considered significant. Results: Seventy-four consecutive patients and 148 breast specimen reports were identified from a database and included in the study. The mean age was 26 years (15-49). Thirty-nine patients had a known history of chest wall binding and 60 patients had undergone preoperative androgen therapy. There was no invasive or in situ carcinoma found in any breast tissue specimens. Thirty-four patients had a benign lesion in one or both breast specimens. Atypical lobular hyperplasia was found in one patient's specimen. A history of chest wall binding was not correlated with any benign lesions (p=0.79) or stromal fibrosis (p=0.94). A history of testosterone use was not correlated with any benign lesions (p=0.35) or stromal fibrosis (p=0.20). Conclusions: The prevalence (1.4%) of significant breast pathology and of benign findings (46%) in our study closely correlates with the rates in the literature. We found no correlation between significant breast pathology or benign lesions and a history of chest wall binding or preoperative androgen therapy. We recommend all breast specimens removed during chest masculinization surgery be sent for pathological evaluation.

Histologic Findings in Surgical Pathology Specimens From Individuals Taking Masculinizing Hormone Therapy for the Purpose of Gender Transition: A Systematic Scoping Review

CONTEXT.—

Transgender men and transmasculine persons experience a discordance between the female sex they were assigned at birth and their gender. They may choose to take hormone therapy and/or undergo surgery to masculinize the body. Understanding the common (and less common) histologic changes present in patients taking masculinizing hormones will empower pathologists to better serve this unique patient population.

OBJECTIVE.—

To summarize histologic findings in surgical pathology specimens from persons taking masculinizing hormones as a part of gender transition.

DATA SOURCES.—

A systematic review of the OVID Medline and PubMed databases was performed to identify all studies describing histologic findings in surgical pathology specimens from transgender men from January 1946 to January 2021.

CONCLUSIONS.—

Publication in this area has markedly increased in the last 2 decades. However, most of the studies identified were descriptive and case reports describing changes seen in specimens removed as a part of masculinizing surgical procedures. Benign histologic findings include stromal hyalinization and epithelial atrophy in the breast, polycystic ovarian syndrome-like changes in the ovary, and transitional cell metaplasia in the cervix. The most commonly reported neoplastic finding was adenocarcinoma of the breast, with rare cases of ovarian, endometrial, cervical, vaginal, pituitary, pancreatic, and cardiovascular neoplasia also reported. Ongoing research in this area is needed to better characterize the histologic findings in persons taking masculinizing hormones to provide a deeper understanding of the effect of these treatments on different tissues and facilitate better patient management.

Incidence of Cancer and Premalignant Lesions in Surgical Specimens of Transgender Patients

BACKGROUND

Gender-affirming surgery is becoming increasingly more common. Procedures including chest masculinization, breast augmentation, vaginoplasty, metoidioplasty, and phalloplasty routinely generate discarded tissue. The incidence of finding an occult malignancy or premalignant lesion in specimens from gender-affirming surgery is unknown. The authors therefore conducted a retrospective review of all transgender patients at their institution who underwent gender-affirming surgery to determine the incidence of precancerous and malignant lesions found incidentally.

METHODS

A retrospective review of transgender patients who underwent gender-affirming surgery at the authors' institution between 2017 and 2018 performed by a single plastic surgeon and a single reconstructive urologic surgeon was conducted. Only transgender patients who underwent gender-affirming surgery that led to routine pathologic review of discarded tissue (mastectomy, vaginoplasty, vaginectomy as part of phalloplasty) were included. Charts were reviewed and patient demographics, duration of hormonal therapy, medical comorbidities, genetic risk factors for cancer, medications (including steroids or other immunosuppressants), pathology reports, and cancer management were recorded.

RESULTS

Between 2017 and 2018, 295 transgender patients underwent gender-affirming surgery that generated discarded tissue sent for pathologic evaluation. During this period, 193 bilateral mastectomies, 94 vaginoplasties with orchiectomies, and eight vaginectomies were performed; 6.4 percent of all patients had an atypical lesion found on routine pathologic evaluation.

CONCLUSIONS

Gender-affirming surgery is increasingly more common given the increase in access to care. The authors' review of routine pathologic specimens generated from gender-affirming surgery yielded a 6.4 percent rate of finding atypical lesions requiring further evaluation. The authors advocate that all specimens be sent for pathologic evaluation.

Apocrine ductal carcinoma in situ associated with testosterone therapy in a transgender individual

We report the first case of apocrine ductal carcinoma in situ (DCIS) in a female-to-male transgender individual on testosterone therapy (TT). The gender confirmation total mastectomy revealed 2 cm DCIS with apocrine cytology, high nuclear grade with associated calcification, and necrosis. Immunohistochemistry revealed the DCIS was negative for ER, positive for AR with HER2/neu overexpression (3+). This patient with negative screening mammography developed apocrine DCIS on TT, suggesting that gender-affirming hormone therapy may have advanced malignant transformation of atypical apocrine cells. This may have implications for increased surveillance within the transgender population.

Testosterone therapy and breast histopathological features in transgender individuals

Testosterone therapy (TT) is administered to enhance masculinization in transgender individuals. The long-term effect of exogenous testosterone on breast tissues remains unclear. Our study evaluated the modulation of breast morphology by TT in transgender individuals with special attention to duration of TT. We reviewed 447 breast surgical specimens from gender affirming chest-contouring surgery, and compared histopathological findings including degree of lobular atrophy, and atypical and non-atypical proliferations between subjects who did (n = 367) and did not (n = 79) receive TT. TT for one patient was unknown. TT for >12 months was associated with seven histopathological features. Longer duration of TT was significantly associated with higher degrees of lobular atrophy (p < 0.001). This relationship remained significant after accounting for age at surgery, ethnicity, body mass index, and presurgical oophorectomy (adjusted p < 0.001). Four types of lesions were more likely to be absent in breast tissues exposed to longer durations of TT: cysts (median = 16.2 months; p < 0.01; adjusted p = 0.01), fibroadenoma (median = 14.8 months; p = 0.02; adjusted p = 0.07), pseudoangiomatous stromal hyperplasia (median = 17.0 months; p < 0.001; adjusted p < 0.001), and papillomas (median = 14.7 months; p = 0.04; adjusted p = 0.20). Columnar cell change and mild inflammation were also less likely to occur in subjects receiving TT (p < 0.05), but were not linked to the duration of TT. Atypia and ductal carcinoma in situ were detected in 11 subjects (2.5%) all of whom received TT ranging from 10.1 to 64.1 months. The incidental findings of high-risk lesions and carcinoma as well as the risk of cancer in residual breast tissue after chest-contouring surgery warrant the consideration of culturally sensitive routine breast cancer screening protocols for transgender men and masculine-centered gender nonconforming individuals. Long-term follow-up studies and molecular investigations are needed to understand the breast cancer risk of transgender individuals who receive TT.

Pathologic Evaluation of Breast Tissue From Transmasculine Individuals Undergoing Gender-Affirming Chest Masculinization

Context.—

Bilateral mastectomy for chest masculinization is one of the gender-affirming procedures for transmasculine individuals.

Objective.—

To optimize gross handling protocols and assess histopathologic findings in transmasculine breast tissue specimens.

Design.—

We identified all gender-affirming mastectomies from 2015 to 2018. We sequentially identified reduction mammoplasty (RM) cases for macromastia from the same period as control. Significant findings were defined as atypical ductal or lobular hyperplasia (ADH, ALH), ductal or lobular carcinoma in situ (DCIS, LCIS), or invasive carcinoma.

Results.—

Significant findings were present in 6 of 211 gender-affirming mastectomies (2.8%) as follows: ADH (n = 5) and LCIS together with ALH (n = 1). By comparison, 19 of 273 RM specimens (7%) yielded significant findings as follows: ALH (n = 11), ADH (n = 4), LCIS (n = 2), DCIS (n = 1), and invasive lobular carcinoma (n = 1). In the gender-affirming group, 142 transmen underwent androgen therapy before surgery, of whom 2 had significant pathologic findings. Thirty and 41 individuals had a family history of breast cancer in the gender-affirming and RM group, of whom 1 and 3 individuals had significant pathologic findings, respectively.

Conclusions.—

Our study demonstrates that we handle transmasculine mastectomy specimens by examining 2.8 times more slides on average than for RMs, with a 2.5 times lower rate of significant pathologic findings. Prior family history of breast cancer or the use of androgen therapy before surgery in gender-affirming individuals did not increase the risk of identifying significant breast lesions. We recommend submitting 4 tissue blocks per mastectomy for individuals undergoing gender-affirming breast surgery.

Histopathologic findings in breast surgical specimens from patients undergoing female-to-male gender reassignment surgery

Breast reduction surgery or mastectomy following administration of androgen therapy is part of the female-to-male gender reassignment process. Details regarding the histopathologic findings in breast tissue from patients undergoing female-to-male gender reassignment surgery are limited. We reviewed hematoxylin and eosin-stained sections of breast tissue from 148 patients who underwent breast reduction surgery or mastectomy as part of the female-to-male gender reassignment process at our institution between January 2014 and May 2017. The spectrum of histologic features in each case was catalogued. The median patient age was 27 years (range 18-60 years). Lobular atrophy was seen to some degree in 73% of cases and was prominent in 42%. A predominantly fibrotic stroma was seen in 45% of cases and areas resembling the fibrous stage of gynecomastia were seen in 41%. Other features included variably ectatic ducts in 96% of cases, cysts in 42%, apocrine metaplasia in 32%, fibroadenomatous change in 27%, usual ductal hyperplasia in 26%, and pseudoangiomatous stromal hyperplasia in 19%. Five cases (3%) demonstrated atypical hyperplasia (atypical ductal hyperplasia in 2; atypical lobular hyperplasia in 2; both atypical ductal hyperplasia and atypical lobular hyperplasia in 1). One case demonstrated high grade ductal carcinoma in situ. No invasive carcinomas were identified. In conclusion, the majority of breast specimens from patients undergoing female-to-male gender reassignment demonstrate at least some degree of lobular atrophy as well as ectatic ducts, fibrous stroma, and areas resembling the fibrous stage of gynecomastia. Only rare cases showed atypical lesions; the clinical significance of these lesions in this setting is uncertain.

Routine histopathological examination after female-to-male gender-confirming mastectomy

Background

The number of transmen seeking gender-confirming surgery has risen steadily throughout the last decade. Pathologists are increasingly confronted with transmale mastectomy specimens. It is not clear whether routine histopathological examination is useful. This study explored the possible benefit of routine investigation through detailed description of lesions encountered in mastectomy specimens after female-to-male gender-confirming surgery.

Methods

Breast tissue from a cohort of transmen was reviewed. The presence of benign and malignant breast lesions was recorded. The number of terminal duct–lobule units (TDLUs) per ten low-power fields (LPFs) was quantified. Information on hormone therapy and morphometry was retrieved for selected patients.

Results

The cohort included 344 subjects with a mean age of 25·8 (range 16–61) years at the time of surgery; the age at surgery decreased significantly over time. Older individuals presented with a significantly higher number of breast lesions. The number of TDLUs per LPF was lower in heavier breasts, but did not correlate with age. Breast lesions, either benign or malignant, were present in 166 individuals (48·3 per cent). Invasive breast cancer was found in two (0·6 per cent); one tumour was an unexpected finding. The number of breast lesions encountered on histopathological examination increased significantly when more tissue blocks were taken.

Conclusion

The discovery of an unexpected breast cancer in a 31-year-old transman emphasizes the importance of thorough routine histopathological examination of mastectomy specimens. The number of tissue blocks taken should be based on age and breast weight.