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Examination of breast tissue recommended after gender-confirming mastectomy

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May 15, 2018

An unexpected case of breast cancer in a transgender man undergoing gender-confirming mastectomy highlights the importance of histopathological examination of mastectomy specimens, according to researchers of an article published in British Journal of Surgery.

“Transmale breast tissue is still a rare specimen in surgical pathology, and there are no well-defined guidelines regarding its examination,” Mieke R. Van Bockstal, MD, PhD, of the department of pathology at Ghent University Hospital in Belgium, and colleagues wrote. “As Ghent University Hospital has gradually become a referral center for patients with gender dysphoria, the number of bilateral mastectomies in transmen has increased there in the last decade. Routine histopathological analysis of transmale mastectomy specimens is questioned.”

Because detailed knowledge of breast histopathology from transgender men is limited, researchers evaluated breast tissue from 344 transgender men who received gender-confirming mastectomies at Ghent University Hospital from Jan. 1, 2005, to July 12, 2017.

Van Bockstal and colleagues recorded the number of benign and malignant breast lesions and calculated the number of terminal duct-lobule units per 10 low-power fields. For select patients, the researchers reviewed data on hormone therapy and morphometry.

The mean age was 25.8 years at the time of surgery; however, researchers noted age at surgery decreased over the study period, from 39 years in 2007 to 23 years in 2017 (P < .001).

Researchers evaluated a mean of five (range, 2-17) tissue blocks per patient. The number of lesions researchers found in histopathological examination increased significantly with the collection of more tissue blocks (P < .001).

The mean number of terminal duct-lobule units per 10 low-power fields was 40 (range, 0 -184). The number of terminal duct-lobule units per 10 low-power fields appeared significantly associated with mean breast weight (P = .006), where heavier breasts tended to have fewer terminal duct-lobule units per 10 low-power fields.

However, the number of terminal duct-lobule units per 10 low-power fields did not vary by age.

Nearly half (48.3%; n = 166) of patients had breast lesions. Of these, two patients (0.6%) had invasive breast cancer. One of these tumors was an “unexpected finding” in a 31-year-old patient who had no family history of breast or ovarian cancer, Van Bockstal and colleagues wrote. The other patient had a family history of breast and endometrial cancer.

Older patients showed significantly more breast lesions than younger patients. The mean age of 178 patients without breast lesions was 23 years (range, 16-46), whereas the mean age of the 166 patients with one or more breast lesions was 29 years (range, 16-61).


These findings prompted researchers to recommend that clinicians use age and breast weight to determine the number of necessary tissue blocks that should be evaluated per patient.

“The discovery of benign breast lesions will not change a patient’s treatment, but the detection of an unexpected breast cancer will,” Van Bockstal said in a press release. “For some of these patients with breast cancer, chemotherapy and axillary lymph node examination will be necessary. In this way, histopathologists provide essential information for both the patient and his physicians.” – by Andy Polhamus

Disclosures: The authors report no relevant financial disclosures.