Residual Oncological Risk After Chest Masculinization Surgery: Invasive Breast Cancer 2 Years After Surgery

Summary:

Chest masculinization surgery (gender-affirming mastectomy [GAM]) is increasingly performed to achieve a masculine chest contour. Unlike oncological mastectomy, GAM prioritizes aesthetic outcomes and may leave residual glandular tissue. Although breast cancer after GAM is uncommon, its occurrence raises important clinical considerations regarding residual risk and surveillance. We report a case of invasive ductal carcinoma arising 2 years after subcutaneous chest masculinization surgery in a transgender patient without testosterone exposure or known hereditary cancer predisposition. Clinical, imaging, pathological findings, and management were reviewed. A 44-year-old transgender man presented with a palpable left chest wall mass 2 years after GAM performed at an outside private clinic, where no preoperative imaging or pathological evaluation had been performed. He had no known hereditary cancer predisposition. Imaging demonstrated a 1.2-cm lesion beneath the nipple–areolar complex. Core biopsy confirmed hormone receptor–positive, HER2-negative invasive ductal carcinoma. Germline testing was negative. The patient underwent completion mastectomy with an axillary evaluation, which revealed stage IIA disease with nodal involvement. Adjuvant chemotherapy, radiotherapy, and endocrine therapy were administered. At 9-month follow-up, the patient remains disease-free. This case highlights that chest masculinization surgery reduces but does not eliminate breast cancer risk. Residual glandular tissue may represent a potential substrate for malignancy, although causation cannot be definitively established. Preoperative imaging should be considered in patients meeting standard breast cancer screening criteria. Excised tissue may warrant histopathological evaluation. Surgeons should provide appropriate counseling and maintain appropriate postoperative cancer surveillance.

Chest masculinization surgery (gender-affirming mastectomy [GAM]) is increasingly performed to create a masculine chest contour in transgender patients. Unlike oncological mastectomy, GAM prioritizes aesthetic outcomes and preservation of the nipple–areolar complex (NAC), which may leave residual fibroglandular tissue.¹ Although breast cancer after GAM is uncommon, residual tissue raises important clinical considerations.²

Most reported cases have been identified incidentally at surgery.^3–6 In contrast, clinically apparent malignancy after GAM remains less well characterized. Variability in real-world practice, including differences in preoperative imaging and specimen evaluation, may influence early detection.

We report invasive ductal carcinoma arising 2 years after GAM in a transgender patient without testosterone exposure or identifiable hereditary cancer predisposition, highlighting considerations in oncological risk, evaluation, and surveillance. This study was approved by the institutional review board of Chulabhorn Royal Academy (IRB 041/2568), and written informed consent for publication of this Case Report was obtained from the patient.

CASE PRESENTATION

A 44-year-old transgender patient presented with a palpable left chest wall mass for 1 month, 2 years after subcutaneous chest masculinization surgery performed at an outside private clinic. Operative records from the initial procedure were unavailable. No preoperative breast imaging had been performed, and the excised tissue was not submitted for histopathological evaluation. The patient had no family history of breast cancer, had never received testosterone therapy, and had not participated in routine breast cancer screening. The patient reported no palpable mass or asymmetrical fullness immediately after the initial surgery. A new palpable mass developed 2 years later.

Physical examination revealed a mobile, 1-cm mass near the previous surgical scar without skin changes (Fig. 1A). No axillary lymphadenopathy was palpable. Mammography and ultrasound screening demonstrated a 1.2-cm hypoechoic lesion beneath the NAC without radiological nodal involvement (Figs. 1B, C). Core biopsy confirmed hormone receptor–positive, HER2-negative invasive ductal carcinoma. Multigene germline testing, including BRCA1/2, was negative. Staging studies showed no distant metastasis.

Fig. 1.

Clinical, radiological, and histopathological findings of the left chest wall lesion. A, Clinical photograph showing a well-circumscribed, 1-cm mass located at the lower outer quadrant of the left chest wall (arrow), without ulceration or overlying skin changes. A previous circumareolar surgical scar is visible. B, Breast ultrasonography demonstrating a 1.2-cm lobulated hypoechoic mass (asterisk) with minimal vascularity in the left periareolar region. C, Mammogram showing a 1-cm mass (arrowhead) near the left nipple without associated microcalcifications or architectural distortion. D, Hematoxylin and eosin staining (original objective magnification, 40×) showing clusters and nests of polygonal cells with eosinophilic cytoplasm and enlarged vesicular nuclei with conspicuous nucleoli, moderate atypia, and frequent mitotic figures. L-CC, left craniocaudal view; R-CC, right craniocaudal view.

The patient underwent completion left mastectomy with sentinel lymph node biopsy. Metastatic involvement was identified, prompting completion axillary lymph node dissection. Final pathology demonstrated a 1.4-cm, grade 2 invasive ductal carcinoma with 2 axillary lymph nodes positive for macrometastasis and extranodal extension (stage IIA) (Fig. 1D). Adjuvant chemotherapy, radiotherapy, and endocrine therapy were administered according to multidisciplinary tumor board recommendations. At 9-month follow-up, the patient remains disease-free and continues tamoxifen therapy without reported complications.

DISCUSSION

Chest masculinization surgery is designed for aesthetic contour rather than oncological risk reduction. Residual glandular tissue may persist, particularly in the subareolar and peripheral regions, where complete excision may compromise vascularity and contour.^1,2 Although this tissue may represent a potential substrate for malignancy, causation cannot be definitively established. Alternative explanations, including occult disease at the time of initial surgery or de novo tumor development, must be considered. Residual glandular tissue varies by surgical technique.^1,7 Although complete operative details were unavailable in this case, the circumareolar incision pattern appeared most consistent with NAC-preserving subcutaneous chest masculinization surgery. Although the tumor was located adjacent to the NAC, its precise origin within the residual glandular tissue (subareolar tissue versus peripheral chest flap) could not be determined. Subcutaneous mastectomy with NAC preservation may leave more subareolar tissue, whereas double-incision techniques with free nipple grafting may allow more extensive removal. Although residual risk persists, GAM may reduce breast cancer risk through partial glandular tissue removal, conceptually similar to breast reduction rather than oncological mastectomy.^1,2 However, the oncological implications of technique-specific differences remain unclear.

Although breast cancer after GAM has been previously reported, it remains uncommon but clinically relevant.^3–6,8,9 Most reported cases are detected incidentally at surgery, whereas this case represents clinically apparent malignancy 2 years postoperatively.^3,4,6 This occurred without testosterone exposure or genetic predisposition. However, without preoperative imaging and histopathological evaluation, it cannot be determined whether the malignancy was occult at the initial surgery, arose from residual glandular tissue, or developed de novo. Evidence regarding testosterone therapy and breast cancer risk remains limited and conflicting.^9,10

A key limitation is the absence of preoperative imaging and histopathological evaluation, preventing distinction between interval cancer and previously unrecognized disease. This case also reflects variability in real-world practice, particularly in procedures performed outside standardized oncological pathways. Postoperative surveillance remains poorly defined.^1,2,7 Mammography may be feasible in selected patients with sufficient residual tissue, although its use may be limited by altered anatomy; therefore, symptom-driven evaluation is critical.² Patients should be educated to perform self-examination and seek prompt evaluation for new palpable abnormalities. Clinicians should maintain a low threshold for imaging, including ultrasonography or breast magnetic resonance imaging when clinically indicated. No standardized screening guidelines currently exist for this population.^1,2,7,9 Patients with hereditary cancer predisposition, prior high-risk breast lesions, or indications for standard breast cancer screening may warrant closer oncological assessment before and after GAM.^1,2,7

Clinically, this case emphasizes that GAM does not eliminate cancer risk. Patients should be counseled that GAM is intended for aesthetic contouring rather than oncological risk reduction, and that residual breast cancer risk, although reduced, is not eliminated.^1,7,9 Preoperative imaging should be considered in patients meeting standard breast cancer screening criteria. Excised tissue may warrant histopathological evaluation, and patients should be counseled regarding ongoing vigilance.^1,2,7 Management follows standard oncological principles; however, delayed diagnosis may occur if prior surgery is assumed to be risk-eliminating. Potential implications of tamoxifen therapy for gender congruence were discussed through shared decision-making. The patient prioritized oncological treatment and proceeded with adjuvant tamoxifen therapy. Longer-term follow-up remains necessary because hormone receptor–positive breast cancer carries a risk of late recurrence. Further studies are needed to guide surveillance.

CONCLUSIONS

Breast cancer can occur after chest masculinization surgery, even without testosterone exposure or hereditary cancer predisposition. Because GAM is not an oncological resection, residual glandular tissue may persist. Although causation cannot be definitively established, this case highlights the gaps in preoperative evaluation and postoperative surveillance. Plastic surgeons should counsel patients that risk is reduced but not eliminated, consider appropriate preoperative imaging, and maintain vigilance for new chest wall abnormalities. Further studies are needed to establish surveillance strategies.

DISCLOSURE

The authors have no financial interests to declare in relation to the content of this article.