Gynaecomastia commonly occurs in adolescents and middle-aged to elderly males (40-60 years), primarily due to a hormonal imbalance favouring oestrogen, and demonstrates glandular tissue proliferation and mammographically appears as a fan-shaped density in the subareolar region.
Description
Gynaecomastia is a benign enlargement of the male breast tissue resulting from an imbalance between oestrogen and androgen action on breast tissue. It’s not a rare condition, seen primarily in adolescents and older men, and is often a source of psychological distress.
Pathogenesis
Gynaecomastia results from an altered oestrogen-androgen ratio leading to a net oestrogen effect on breast tissue. This imbalance can occur due to increased oestrogen production, decreased androgen production, increased breast sensitivity to normal circulating oestrogen, or use of medications that mimic oestrogen or inhibit androgen. The result is enlargement of the male breast secondary to ductal hyperplasia and stromal proliferation.
Subtypes
Gynaecomastia can be classified into three types based on histopathological characteristics:
- Florid type (early stage, typically within one year of onset)
- Fibrous type (intermediate stage, one year to several years after onset)
- Fatty type (chronic stage, several years after onset)
Epidemiology, Risk Factors & Associations
Gynaecomastia has a broad spectrum of presentation across age groups and is most prevalent at times of hormonal fluctuation. It peaks during three phases of life: neonatal period, adolescence, and old age.
- Neonatal period: Gynaecomastia affects up to 60-90% of newborns due to maternal oestrogens crossing the placenta. This type of gynaecomastia usually resolves within a few weeks after birth.
- Puberty: Gynaecomastia occurs in 50-60% of adolescent boys between the ages of 10 and 16 years due to an imbalance between oestrogen and testosterone. It is often bilateral and symmetrical and typically resolves spontaneously within one to two years.
- Old age: Gynaecomastia is present in 20-40% of men aged 50 to 80 years, largely due to decreasing testosterone production.
Risk factors and associations include:
- Endocrine disorders: Disorders causing hypoandrogenism or hyperoestrogenism, such as hyperthyroidism (incidence up to 40% in hyperthyroid patients), hypogonadism, and Klinefelter syndrome (seen in up to 80% of affected males) significantly increase the risk of developing gynaecomastia.
- Medications: Accounts for up to 20-25% of adult cases. Drugs like spironolactone, digitalis, cimetidine, ketoconazole, and certain antiretroviral drugs have been associated with gynaecomastia.
- Alcohol and drugs: Alcohol can decrease testosterone levels and increase oestrogen levels, leading to gynaecomastia. Illicit substances such as marijuana, heroin, and amphetamines have also been linked with the development of gynaecomastia.
- Obesity: Due to peripheral conversion of androgens to oestrogens in adipose tissue, obese males have a higher risk of developing gynaecomastia.
- Chronic liver disease: Cirrhosis or chronic liver disease can lead to gynaecomastia in up to 8% of cases due to altered metabolism of hormones.
- Chronic kidney disease and dialysis: Increased prevalence of gynaecomastia has been reported in these patients due to hormonal imbalances.
- Neoplasms: Tumours involving the adrenal glands or testes, as well as hCG-secreting tumours, can increase oestrogen levels and lead to gynaecomastia.
- Testicular tumours: Germ cell, Leydig, Sertoli
- Nontesticular tumours: Adrenal, liver, lung, renal [ectopic human chorionic gonadotropin (HCG)]
Clinical Features
- Typically presents as a palpable, tender, firm, mobile, subareolar mass.
- May be associated with nipple discharge, skin changes, and breast asymmetry.
Complications
- No known risk of malignant transformation.
- Psychological distress and cosmetic concerns.
Pathological Features
Histopathology
- Macroscopic: Enlarged glandular tissue with increased stromal fibrosis. The tissue can be soft in early stages and firmer in later stages due to fibrosis.
- Microscopic: Gynaecomastia demonstrates a proliferation of ductal epithelium and periductal stroma.
- Florid type (within first year of onset): This subtype shows a marked proliferation of ductal epithelium, with the ducts often lined by several layers of epithelial cells. The stroma shows moderate to marked edema and is infiltrated by chronic inflammatory cells, including lymphocytes and plasma cells. The ducts may contain secretion, and there might be epithelial hyperplasia, but without the formation of secondary lumens.
- Fibrous type (1-3 years after onset): There is less ductal proliferation and the epithelium is often flattened. The stroma is denser due to increased fibrosis, and there is a reduction in the degree of inflammatory infiltrate compared to the florid type. Residual ducts are set in dense fibrous tissue.
- Fatty type (several years after onset): This subtype is characterised by adipose tissue replacing fibrous tissue. There is significant regression of ductal elements and the fibrous stroma, replaced by fatty infiltration. Ductal structures, when present, are sparse and atrophic.
Serology
- May show altered hormone levels, particularly elevated oestrogen or reduced testosterone.
Radiological Features
General Features
- Diagnostic investigation is usually with bilateral mammograms when age > 25 years.
- US rarely necessary to confirm unless age < 25 years, in which case mammograms may be performed after if required.
- Exclude male breast cancer, which is usually appears as a circumscribed or spiculated mass with convexity posteriorly, often eccentric to nipple
MG
- Classic features of gynecomastia include subareolar fan- or flame-shaped density, which emanates from the nipple and blends into surrounding fat
- Usually asymmetric.
CT
- Non-contrast: Diffusely increased density of breast tissue.
- C+ Arterial: May show enhancement of glandular tissue.
- C+ Venous: Enhancement may persist.
MRI
- T1: Isointense to slightly hyperintense to muscle.
- T2: Heterogeneously hyperintense.
- T1 Gad+: Moderate to marked homogeneous enhancement.
US
- B-mode: Hypoechoic, homogeneous flamed-shape tissue behind the nipple, tapering peripherally
- Colour: May demonstrate increased vascularity.
NM
- Not typically applicable.
Grading and Staging
- Not typically applicable.
Diagnosis
- Clinical diagnosis supported by imaging findings. Hormonal assay may help identify underlying cause.
- Unlike female breasts, there is usually no need to biopsy a palpable mass in a male patient when imaging suggests gynaecomastia
Differential Diagnosis
- Breast cancer: uncommon in males, but presents as irregular, ill-defined mass with or without associated skin or nipple retraction.
- Lipomastia (pseudogynaecomastia): enlargement of male breasts due to increased adipose tissue, typically seen in obese men.
Prognosis
- Generally good with treatment, but depends on underlying cause.
Management
- Depends on underlying cause. In idiopathic or physiologic gynaecomastia, reassurance and observation are usually sufficient. Medical therapy may be tried in early stages, and surgical intervention may be required for persistent or severe cases.