What are the next steps for a male with a unilateral breast mass and unremarkable mammogram (magnetic resonance imaging) and ultrasound findings?

Next Steps for Male with Unilateral Breast Mass and Unremarkable Imaging

For a male patient with a unilateral breast mass and unremarkable mammogram and ultrasound findings, tissue biopsy is the recommended next step to definitively rule out malignancy.

Diagnostic Algorithm for Male Breast Mass

Understanding the Clinical Context

• Male breast cancer accounts for <1% of all male cancers but must always be excluded when physical examination findings are suspicious or inconclusive 1
• The most common cause of male breast masses is gynecomastia (83%), with breast cancer being relatively rare (3%) 2
• However, unremarkable imaging does not completely exclude malignancy

Imaging Findings Interpretation

• Mammography has high sensitivity (92-100%) and specificity (90-96%) with negative predictive values of 99-100% 3
• Ultrasound typically complements mammography with sensitivity of 88.9-100% and specificity of 74-95.3% 3
• When combined, mammography and ultrasound have a negative predictive value of 99.8% 3
• Despite these high values, false negatives can occur, particularly with complex masses 3

Next Steps After Unremarkable Imaging

1. Tissue Biopsy:

   • Core needle biopsy is preferred for definitive tissue diagnosis
   • Ultrasound-guided biopsy is recommended for palpable masses even with normal imaging
   • Fine-needle aspiration cytology can be considered as an alternative

2. Clinical Correlation Factors to Consider:

   • Age: Men >25 years have higher risk (median age of male breast cancer is 63 years) 3
   • Mass characteristics: Hard, fixed, eccentric to nipple masses are more concerning
   • Skin changes: Nipple retraction, skin dimpling, or axillary lymphadenopathy warrant biopsy
   • Duration: Recent onset masses are more concerning than long-standing ones

Important Considerations

Pitfalls to Avoid

• Do not dismiss a palpable mass based on normal imaging alone: Unlike in women, relatively benign imaging findings in men should be considered suspicious 3
• Do not rely solely on symptoms: Lack of pain is not helpful in differentiating gynecomastia from breast cancer 2
• Avoid assuming bilateral disease: Male breast cancer is typically unilateral, while gynecomastia is bilateral in approximately 45% of cases 4

Special Circumstances

• If the patient is <25 years old with typical gynecomastia features, close clinical follow-up may be considered instead of immediate biopsy 3
• If the patient has known risk factors for male breast cancer (BRCA mutations, Klinefelter syndrome, family history), biopsy should be strongly considered regardless of imaging

The high negative predictive value of combined mammography and ultrasound (99.8%) is reassuring, but given the palpable finding and potential consequences of missed malignancy, tissue diagnosis remains the gold standard approach for definitive evaluation.