What is the likely cause of a single or bilateral enlarged nipple in a 13‑year‑old male and how should it be managed?

Enlarged Nipple in a 13-Year-Old Male

This is almost certainly physiologic pubertal gynecomastia, which is a normal finding in up to 50% of adolescent males at this age and requires no imaging or treatment—only reassurance. 1, 2

What This Likely Is

Pubertal gynecomastia is benign breast tissue enlargement that typically appears at ages 13-14 years due to temporary hormonal imbalances between estrogen and androgen during puberty. 2, 3 The condition presents as:

• A soft, rubbery, or firm mobile mass directly under the nipple 1
• Often tender or painful, especially in the first 6 months 1
• Bilateral in approximately 50% of cases (unilateral is also completely normal) 1
• Self-limited, resolving spontaneously in 75-90% of adolescents over 1-3 years 3, 4

No Imaging or Testing Needed

For a 13-year-old with clinical findings consistent with gynecomastia, no imaging is routinely recommended. 1 The American College of Radiology explicitly states that unnecessary imaging in clear cases of gynecomastia leads to additional unnecessary benign biopsies without improving outcomes. 1

Most adolescent males with breast symptoms can be diagnosed based on clinical findings alone without any imaging. 1

When to Consider Further Evaluation

Imaging (ultrasound for boys under 25) is only indicated if: 1

• The mass is hard, fixed, or eccentric (off to the side rather than directly under the nipple)
• There is bloody nipple discharge
• There is skin or nipple retraction
• The differentiation between benign disease and breast cancer cannot be made clinically

Important caveat: Male breast cancer is extremely rare in adolescents—the median age is 63 years. 1

Management Algorithm

Step 1: Reassurance (Standard of Care)

Reassurance remains the standard of care for physiologic gynecomastia in adolescents. 2 Explain that:

• This is a normal part of puberty affecting up to 50% of boys 2, 5
• It will likely resolve on its own within 1-3 years 3, 4
• No treatment is medically necessary 2

Step 2: Address Psychological Impact

Gynecomastia commonly causes significant psychological stress, embarrassment, and depression in adolescents. 3, 6 Assess the emotional impact and provide appropriate support. 2

Step 3: Observation Period

Monitor for spontaneous resolution over the next 1-3 years. 3 Up to 50% of cases with non-cyclical breast symptoms resolve spontaneously. 1

Step 4: Consider Medical Therapy (Only If Persistent Beyond 12 Months AND Causing Substantial Distress)

If gynecomastia persists beyond 12 months and causes substantial tenderness or embarrassment, pharmacological therapy may be considered: 3, 6

• Tamoxifen (a selective estrogen receptor modulator) is the most studied and effective medication, found to be safe with minimal side effects 6
• Pharmacological therapy is most effective when given early in the course and works best for small to moderate breast enlargement 3
• Important limitation: Neither tamoxifen nor other medications are universally FDA-approved for gynecomastia treatment because risks and benefits have not been completely studied 3

Step 5: Surgical Referral (Reserved for Severe Cases)

Surgery is reserved for severe cases causing significant psychological distress and is typically offered towards the end of puberty after allowing time for spontaneous resolution. 6

What to Rule Out (History Taking)

Ask specifically about: 2, 4

• Medications: Anabolic-androgenic steroids, spironolactone, ketoconazole, finasteride, or other drugs 7, 2
• Illicit substances: Cannabis use (especially chronic use started at young age) 7, 2
• Herbal products or supplements 2
• Testicular examination findings: Check for masses or abnormalities that might suggest hormone-secreting tumors 1

Common Pitfalls to Avoid

• Do not order imaging for typical pubertal gynecomastia—this leads to unnecessary biopsies and anxiety 1
• Do not confuse true gynecomastia with pseudogynecomastia (fatty tissue in overweight boys), though both are benign 1
• Do not rush to pharmacological treatment—most cases resolve spontaneously and medications lack full FDA approval for this indication 3, 6
• Do not dismiss the psychological impact—assess and address emotional distress even when reassuring about the benign nature 2, 3