Benign proliferation of glandular breast tissue in males from altered estrogen-to-androgen ratio.
Also known as: gynecomastia, male breast enlargement, pubertal gynecomastia
Overview
Benign enlargement of the male breast from proliferation of glandular ductal and stromal tissue, distinguished from pseudogynecomastia (lipomastia), which is adipose accumulation without true glandular tissue. Defined clinically by a palpable, concentric, rubbery or firm subareolar mound of tissue ≥0.5 cm in diameter.
Epidemiology
Trimodal distribution: neonatal (transient, from maternal estrogen, 60-90%), pubertal (peak at 13-14 years, resolves within 1-2 years in most), and older adult (incidence rises after age 50, prevalence up to 65% over age 70). Pathologic causes account for a minority of cases but must be excluded.
Try two board-style Gynecomastia questions
Real questions from the FirstPassPA bank, with the full explanation. Pick an answer — no signup, no email.
Question 1ReproductiveMedium
A 15-year-old boy is brought in by his mother for a unilateral right breast lump and intermittent bloody nipple discharge over the past 2 months. He denies medication or supplement use, including anabolic steroids. Exam shows a firm, eccentric 2 cm mass beneath the right nipple, tender to palpation, with serosanguinous discharge expressible from the nipple; the contralateral breast is normal and Tanner stage is 4. There is no axillary lymphadenopathy and the testes are normal. Which of the following is the most appropriate next step in evaluation?
ASerum beta-hCG and testosterone
BCore needle biopsy of the mass
CMammography
DBreast ultrasound
EReassurance and reevaluation in 6 months
Reveal answer & full explanation
Correct answer: D — Breast ultrasound
ASerum beta-hCG and testosterone
BCore needle biopsy of the mass
CMammography
DBreast ultrasound✓
EReassurance and reevaluation in 6 months
Why Breast ultrasound is correct
Pubertal gynecomastia is common but is typically bilateral or asymmetric, rubbery, concentric, and non-bloody
Unilateral, eccentric, firm, or rapidly enlarging masses, and especially bloody nipple discharge, are red flags that mandate imaging to rule out a discrete lesion such as fibroadenoma, intraductal papilloma, or, rarely, a malignancy
In a male younger than 25, breast cancer is exceedingly rare and ultrasound is the preferred first study: the ACR Appropriateness Criteria rate it the initial study for an indeterminate breast mass below age 25 and rate it appropriate at any age when nipple discharge or another suspicious finding is present, and it characterizes the lesion without radiation
Why the others are wrong
Reassurance and reevaluation in 6 months — appropriate for typical bilateral pubertal gynecomastia but not when red flags such as bloody discharge are present
Serum beta-hCG and testosterone — part of the workup for true bilateral gynecomastia to evaluate hCG-secreting germ cell tumors or hypogonadism, but imaging takes priority for a focal mass with bloody discharge
Mammography — the initial study for an indeterminate breast mass in men 25 and older; ACR also rates it appropriate at any age when the exam is suspicious for cancer, but in a 15-year-old, in whom breast cancer is exceedingly rare, ultrasound comes first and mammography is added if the ultrasound findings are suspicious
Core needle biopsy of the mass — tempting because a firm, eccentric mass with bloody discharge raises concern for a discrete lesion, but tissue sampling follows imaging rather than replacing it; ultrasound first characterizes the mass without radiation and determines whether and where a biopsy is needed.
Additional high-yield points
Bloody nipple discharge in any patient, male or female, is never physiologic and always requires imaging
Question 2EndocrineEasy
A 14-year-old boy is brought in by his mother for bilateral breast tenderness and swelling that he first noticed about 3 months ago. He reports the area is sensitive when his shirt rubs against it and he is self-conscious in the locker room. He takes no medications and uses no supplements, alcohol, or marijuana. On exam, BMI is 21 kg/m2. Palpation of each breast with a pinch test from the lateral edge inward reveals a concentric, rubbery, mobile disc of tissue about 2 cm in diameter centered beneath each areola, rising above the surrounding chest wall fat. There is no skin retraction, nipple discharge, or axillary lymphadenopathy. Testicular exam shows normal-sized, symmetric testes without masses. Which of the following is the most likely diagnosis?
ALipomastia of the chest
BLipoma of the chest wall
CGynecomastia of hypogonadism
DGynecomastia of hyperthyroidism
EGynecomastia of puberty
Reveal answer & full explanation
Correct answer: E — Gynecomastia of puberty
ALipomastia of the chest
BLipoma of the chest wall
CGynecomastia of hypogonadism
DGynecomastia of hyperthyroidism
EGynecomastia of puberty✓
Why Gynecomastia of puberty is correct
Gynecomastia is benign proliferation of glandular ductal and stromal tissue, felt as a concentric, rubbery or firm, mobile subareolar disc at least 0.5 cm in diameter that rises above the surrounding fat on the pinch test.
This case is the textbook pubertal presentation: a 13-14 year old boy with tender, bilateral subareolar glandular tissue of recent onset (proliferative phase, first 6 months) and a normal testicular exam, with no medication, substance, or systemic cause. Most pubertal cases resolve spontaneously within 1-2 years, so observation and reassurance are appropriate.
Reassuring features that argue against malignancy: bilateral (about 75% of gynecomastia), concentric and central rather than eccentric, mobile rather than fixed, and no skin retraction, nipple discharge, or lymphadenopathy.
Why the others are wrong
Lipoma of the chest wall - a soft, mobile mass that is not centered under the areola and lacks a glandular component on ultrasound. The concentric subareolar location and rubbery glandular texture here point to gynecomastia, not a lipoma.
Gynecomastia of hypogonadism - testicular failure (Klinefelter syndrome is the classic adolescent example) lowers testosterone, raises the estrogen-to-androgen ratio, and does produce bilateral glandular gynecomastia, but it comes with small, firm or atrophic testes and, when primary, low testosterone with high LH and FSH; this boy's testes are normal-sized and symmetric, so a hypogonadal cause is not supported.
Lipomastia of the chest - pseudogynecomastia, adipose accumulation without true glandular tissue; it feels uniformly soft and diffuse with no discrete subareolar mound, and is seen in higher-BMI patients. This patient has a normal BMI and a discrete rubbery glandular disc on the pinch test.
Gynecomastia of hyperthyroidism - hyperthyroidism raises SHBG and peripheral aromatization of androgens to estrogens and is a recognized systemic cause of gynecomastia, but it would be expected to bring symptoms such as weight loss, palpitations, tremor, or heat intolerance, none of which he reports; tender bilateral subareolar discs at 14 years with normal testes fit the far more common physiologic pubertal type.
That's 2. Get 7,700+ more.
Unlock the full FirstPassPA bank: 7,700+ board-style questions, flashcards, and an AI tutor that explains every answer. Your 7-day free trial includes everything, and there's no credit card required.
You've read your 2 free diagnosis previews. Create your free account to unlock the full Gynecomastia outline — plus all 514 diagnoses, 7,700+ board-style questions, flashcards, and an AI tutor. Your 7-day free trial includes everything, and there's no credit card required.
Imbalance between stimulatory estrogen action and inhibitory androgen action on breast tissue drives ductal epithelial proliferation, periductal stromal edema, and glandular hyperplasia. The ratio shifts when estrogen rises (exogenous, tumor, peripheral aromatization), when androgens fall (hypogonadism, anti-androgens), or when binding proteins shift free hormone fractions (SHBG changes in cirrhosis or hyperthyroidism). Long-standing gynecomastia (>12 months) progresses to fibrosis and is unlikely to regress with medical therapy.
Clinical presentation
Symptoms
Bilateral or unilateral breast enlargement, often tender in the proliferative phase (first 6 months)
Sensitivity to clothing pressure
Cosmetic and psychological distress, particularly in adolescents
Symptoms of an underlying cause: testicular pain or mass, weight changes, virilization loss, alcohol use, medication exposure
Signs / physical exam
Concentric, rubbery or firm, mobile subareolar disc of tissue at least 0.5 cm in diameter — pinch test from the lateral edge inward identifies the firm edge of glandular tissue rising above surrounding fat
Bilateral in approximately 75% of cases; unilateral findings warrant heightened scrutiny for tumor or cancer
Testicular examination is mandatory — look for atrophy (Klinefelter, hypogonadism), mass (germ cell tumor), or asymmetry
Evidence of liver disease, thyroid disease, or hypogonadism (gynoid fat distribution, loss of body hair, small testes)
Classic findings
Concentric firm rubbery subareolar tissue rising above surrounding chest wall fat; pubertal gynecomastia is typically tender and bilateral with spontaneous regression.
Differential diagnosis
Pseudogynecomastia (lipomastia) — Soft, diffuse adipose tissue without a discrete subareolar mound; no symmetric concentric tissue under areola; weight loss reduces it
Male breast cancer — Unilateral, eccentric, hard, fixed mass, often with skin retraction, nipple discharge or inversion, or axillary lymphadenopathy; mammography and biopsy
Lipoma — Soft, mobile, non-tender mass not centered under the areola; ultrasound shows fatty tissue without glandular component
Neurofibroma or sebaceous cyst — Superficial, well-circumscribed, may have characteristic stigmata of neurofibromatosis; not subareolar glandular
Mastitis or breast abscess — Erythema, warmth, tenderness, fever; usually unilateral; antibiotics and drainage
Diagnostic workup
Diagnostic criteria
Clinical diagnosis: palpable concentric glandular tissue ≥0.5 cm beneath the areola. Adolescent with typical bilateral, tender pubertal gynecomastia and normal testes: no labs or imaging; reassure and re-examine in 3-6 months. Evaluate further if rapidly enlarging, >5 cm, unilateral or atypical, persisting beyond about 2 years, small testes, or in any prepubertal child. Adult-onset gynecomastia: medication and substance history, testicular exam, and targeted labs even when a cause seems apparent; breast imaging only for an indeterminate or suspicious mass.
Labs
Total and free testosterone (8 AM)
LH and FSH
Estradiol
Beta-hCG (any elevation suggests germ cell tumor or other hCG-secreting tumor)
TSH and free T4 (hyperthyroidism increases SHBG and aromatization)
LFTs, BUN/creatinine (chronic liver and kidney disease)
Prolactin if galactorrhea, sexual dysfunction, or visual symptoms
DHEA-S if rapid onset, virilizing features, or adrenal mass on imaging
Imaging
Testicular ultrasound if hCG elevated, testicular mass palpated, or unexplained gynecomastia in young adult
No routine breast imaging for clinically typical gynecomastia; for an indeterminate breast mass, ultrasound first if younger than 25 and mammography (or digital breast tomosynthesis) first if 25 or older; when the exam is suspicious for cancer (hard or fixed mass, nipple retraction or discharge, axillary nodes), mammography and ultrasound are appropriate at any age, with core needle biopsy of suspicious findings (ACR Appropriateness Criteria); in adolescents, in whom breast cancer is exceedingly rare, ultrasound is the usual first study
MRI sella if hyperprolactinemia is identified
CT chest/abdomen if hCG elevated without testicular source (extragonadal germ cell or ectopic hCG-secreting tumor)
Diagnostic algorithm
flowchart TD
A[Male breast enlargement] --> B[Pinch test]
B --> C{Firm concentric<br/>subareolar tissue?}
C -->|No - diffuse soft fat| D[Pseudogynecomastia<br/>weight management]
C -->|Yes - true gynecomastia| E[History + medication<br/>review + testicular exam]
E --> F{Red flags?<br/>unilateral, hard, fixed,<br/>nipple discharge,<br/>rapid onset, testicular mass}
F -->|Yes| G["Breast imaging: US first if age <25,<br/>mammography if age 25+ or exam suspicious<br/>+/- testicular US + hCG"]
F -->|No| P{Adolescent with typical<br/>bilateral tender pubertal<br/>pattern, normal testes?}
P -->|Yes| Q["Reassure; re-examine in 3-6 months<br/>(most resolve within 1-2 yr)"]
P -->|No - adult onset or atypical| H["Basic labs:<br/>testosterone, LH, FSH,<br/>estradiol, hCG, TSH,<br/>LFTs, creatinine, prolactin"]
H --> I{Identified cause?}
I -->|Yes| J[Treat underlying<br/>cause / stop drug]
I -->|No, idiopathic| K{"Duration <12 mo<br/>and painful?"}
K -->|Yes| L["Consider tamoxifen trial<br/>(off-label)"]
K -->|No - fibrotic >12 mo| M[Surgical referral<br/>if desired]
Diagnostic and management algorithm for gynecomastia.
Treatment
First-line
Identify and treat or remove the underlying cause when possible — discontinue offending medications, treat hypogonadism, manage liver or thyroid disease
Observation for pubertal gynecomastia — most resolve spontaneously within 1-2 years
Patient education and reassurance for asymptomatic, stable, long-standing gynecomastia
Second-line / adjunct
Selective estrogen receptor modulator (SERM) — tamoxifen 10-20 mg daily, raloxifene — most effective in the early proliferative phase (<12 months) when tissue is still glandular rather than fibrotic; off-label but supported in expert guidance
Aromatase inhibitor — anastrozole, letrozole — limited evidence; consider only in select cases (e.g., aromatase excess syndrome)
Testosterone replacement for confirmed hypogonadism — testosterone cypionate IM, testosterone gel, intranasal testosterone — it may improve gynecomastia by restoring the androgen-to-estrogen ratio, but aromatization to estradiol can occasionally worsen it
Surgery — subcutaneous mastectomy with liposuction — for long-standing (>1 year) fibrotic gynecomastia, large breasts (≥5 cm), severe psychological distress, or failed medical therapy
Complications
Persistent cosmetic deformity once fibrosis sets in (>12 months)
Psychological distress, body image disturbance, and social withdrawal, particularly in adolescents
Missed underlying malignancy (testicular germ cell tumor, male breast cancer, adrenal or lung tumor)
Treatment-related: hot flashes and thromboembolism with SERMs; surgical complications including hematoma, contour irregularity, nipple necrosis, and scarring
PANCE pearls
Distinguish true gynecomastia from pseudogynecomastia by the pinch test — slowly bring thumb and forefinger together from lateral to medial; true gynecomastia is felt as a discrete rubbery resistance, pseudogynecomastia feels uniformly soft.
Hard, fixed, or skin-tethered breast lesions in men (suspicious for cancer) require mammography and core biopsy regardless of age, whereas an indeterminate unilateral or eccentric mass in a male younger than 25 is imaged first with ultrasound — male breast cancer accounts for <1% of all breast cancers but has a worse stage-matched prognosis when delayed.
Always examine the testes — a testicular mass in a young man with new gynecomastia is a germ cell tumor until proven otherwise.
Drug-induced gynecomastia (spironolactone, cimetidine, ketoconazole, finasteride, anabolic steroids, antiretrovirals) frequently improves within 3 months of stopping the offending agent if the tissue has not become fibrotic.
Long-standing fibrotic gynecomastia (>1 year) is unlikely to regress with medical therapy — set expectations and refer for surgery if intervention is desired.
References
Endocrine Society 2018 — Testosterone Therapy in Men with Hypogonadism: An Endocrine Society Clinical Practice Guideline (Bhasin et al., J Clin Endocrinol Metab 2018)
EAA 2019 — EAA Clinical Practice Guidelines — Gynecomastia Evaluation and Management (Kanakis et al., Andrology 2019)
Educational use only. This outline is a study aid for PA students and is not medical advice or a substitute for clinical judgment. FirstPassPA is an independent study tool and is not affiliated with, endorsed by, or sponsored by NCCPA or PAEA. PANCE® and PANRE® are registered trademarks of the National Commission on Certification of Physician Assistants; End of Rotation™ is a program of the Physician Assistant Education Association.