Does BRCA (Breast Cancer Gene) mutation cause gynecomastia?

BRCA Mutations and Gynecomastia

BRCA mutations do not cause gynecomastia. While BRCA mutations significantly increase the risk of various cancers, there is no established link between BRCA mutations and the development of gynecomastia in males.

BRCA Mutations and Their Known Cancer Risks

BRCA mutations are primarily associated with increased cancer risks:

• Female BRCA1 mutation carriers have an estimated 48.3% cumulative risk of ovarian cancer by age 70, while BRCA2 mutation carriers have a 20.0% cumulative risk 1
• Male carriers of BRCA1 mutations have a 1.2% lifetime risk of breast cancer 1
• Male carriers of BRCA2 mutations have a significantly higher risk (5-10%) of developing breast cancer compared to BRCA1 carriers 2
• BRCA2 mutations in particular are associated with increased risk of prostate cancer, with a cumulative lifetime risk of 60% (compared to 29% for BRCA1 carriers) 1
• Additional cancer risks include pancreatic cancer (up to 2%), stomach, and head and neck cancers 1

Male Breast Cancer vs. Gynecomastia

It's important to distinguish between male breast cancer and gynecomastia:

• Gynecomastia is benign enlargement of male breast tissue, typically bilateral, and is the most common abnormality of the male breast 3
• Male breast cancer is rare, accounting for <1% of all male cancers 4
• While BRCA mutations (especially BRCA2) increase the risk of male breast cancer, they have not been documented to cause gynecomastia 2

Common Causes of Gynecomastia

Gynecomastia typically results from:

• Physiological causes: can occur in newborns, during puberty, and in men over age 65 3
• Medical conditions that alter the estrogen-testosterone balance 3
• Medications: many drugs are known to cause gynecomastia 3, 4
• In a study of 36 male patients with unilateral breast masses, 83% had gynecomastia, and 60% of these patients had a history of medical conditions or medications known to cause gynecomastia 4

Clinical Implications for BRCA Carriers

For individuals with BRCA mutations, clinical management focuses on cancer surveillance and risk reduction:

• Male BRCA carriers should undergo appropriate cancer screening, particularly for breast and prostate cancers 2
• The National Comprehensive Cancer Network provides guidelines for surveillance in BRCA mutation carriers, including breast imaging surveillance beginning at age 25 for women 5
• Risk-reducing strategies, including surgical and pharmacological approaches, should be considered for BRCA mutation carriers 5

Important Considerations

• When evaluating male breast enlargement, clinicians should consider the full differential diagnosis, including gynecomastia (most common), lipomas, and breast cancer 4
• For unilateral male breast masses, the risk of breast cancer is low but should not be dismissed, especially in BRCA2 carriers 4
• Basic diagnostic evaluation of breast enlargement in males includes thorough history, physical examination, breast and testicular sonography, and laboratory testing for hormonal imbalances 3

In conclusion, while BRCA mutations significantly increase the risk of various cancers including male breast cancer (particularly BRCA2), there is no evidence that BRCA mutations directly cause gynecomastia.