In a male patient with a mobile subareolar mass under the left nipple present for about a year, now enlarging and without nipple discharge, what is the appropriate diagnostic and management approach?

Diagnostic Approach to a Mobile Subareolar Mass in a Male Patient

Initial Clinical Assessment

In a male patient with a mobile subareolar mass that has been present for one year and is now enlarging without nipple discharge, you must proceed directly to diagnostic imaging with mammography and ultrasound, as male breast masses carry a 23-57% malignancy risk and require the same rigorous evaluation as females. 1

The key clinical features to document are:

• Mobility and location: A mobile subareolar mass suggests either gynecomastia or a discrete lesion (papilloma, carcinoma) 1
• Duration and growth: One year duration with recent enlargement is concerning—gynecomastia typically stabilizes, while malignancy progressively enlarges 1
• Absence of discharge: While reassuring, this does NOT exclude malignancy, as only a subset of male breast cancers present with nipple discharge 1

Mandatory Diagnostic Imaging

First-Line: Diagnostic Mammography PLUS Ultrasound

Order diagnostic mammography (or digital breast tomosynthesis) with targeted ultrasound of both breasts, focusing on the subareolar region. 1, 2

• Mammography will differentiate between:

  • Gynecomastia patterns (nodular, dendritic, or diffuse glandular) 1
  • Suspicious features: mass with irregular margins, architectural distortion, or microcalcifications 1
  • Pseudogynecomastia (fatty tissue only) 1

• Ultrasound is critical because:

  • It has higher sensitivity than mammography for detecting masses in dense tissue 1
  • It can characterize solid versus cystic lesions and guide biopsy 1
  • Male breast tissue is often dense, limiting mammographic sensitivity 1

Common Pitfall to Avoid

Do NOT assume this is benign gynecomastia based on clinical examination alone, even if it feels soft and mobile. Approximately 50% of men with breast cancer have coexisting gynecomastia, and the two conditions can be indistinguishable on palpation. 1

Management Based on Imaging Results

If BI-RADS 4 or 5 (Suspicious or Highly Suggestive of Malignancy)

Proceed immediately to image-guided core needle biopsy (ultrasound-guided preferred if a discrete mass is identified). 1, 2

• Core needle biopsy is superior to fine needle aspiration for accurate histologic diagnosis and grading 1
• Place a marker clip at the biopsy site for surgical planning if malignancy is confirmed 3

If BI-RADS 1-3 (Negative, Benign, or Probably Benign) BUT Mass is Enlarging

This scenario requires heightened vigilance. Even with reassuring imaging:

• Short-interval follow-up at 3-6 months with repeat clinical examination and imaging is mandatory 1, 2
• If the mass continues to enlarge on follow-up, tissue sampling is required regardless of benign imaging appearance 1
• Consider excisional biopsy if the patient or clinician remains concerned, as a negative mammogram does NOT reliably exclude malignancy in males 1

If Imaging Shows Classic Gynecomastia Pattern

Even with typical gynecomastia findings:

• Document the pattern (nodular, dendritic, or diffuse) and measure the size 1
• Investigate underlying causes: medications (antihypertensives, psychoactive drugs, opiates), hormonal imbalances, chronic liver disease, or testicular tumors 1
• Close surveillance is still warranted given the one-year duration with recent growth—consider 6-month follow-up imaging to confirm stability 1

Age-Specific Considerations

While this patient's exact age is not specified, the approach differs slightly by age:

• Under 25 years: Ultrasound may be the initial modality, with mammography added if ultrasound is indeterminate 1
• 25 years and older: Diagnostic mammography is the first-line study, supplemented by ultrasound 1, 4

Given the one-year duration and growth, this patient is likely older, making mammography essential.

Critical Red Flags That Mandate Biopsy

Regardless of imaging appearance, proceed directly to tissue diagnosis if any of these features are present:

• Skin or nipple retraction 1
• Fixed or hard mass on examination 1
• Palpable axillary lymphadenopathy 1
• Bloody or spontaneous nipple discharge (though absent here) 1, 2

Why Male Breast Masses Require Aggressive Workup

Male breast cancer is rare (<1% of all breast cancers) but presents at advanced stages with larger tumors and higher rates of nodal metastases. 1 The median age is 63 years, but 6% occur in men under 40. 1 The exceptionally high malignancy rate in males with breast symptoms (23-57% with nipple discharge, and significant risk with palpable masses) justifies the same rigorous imaging protocol used in females. 1, 4

Summary Algorithm

1. Obtain diagnostic mammography + ultrasound of both breasts (subareolar focus) 1, 2
2. If BI-RADS 4-5: Image-guided core needle biopsy 1
3. If BI-RADS 1-3 but enlarging: Short-interval follow-up (3-6 months) with repeat imaging; biopsy if growth continues 1, 2
4. If classic gynecomastia: Investigate underlying causes and ensure close surveillance 1
5. Never dismiss a growing mass in a male patient without tissue diagnosis or documented stability over time 1