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Gynaecomastia

Dr Ian Bickle and Dr Jeremy Jones et al.

Gynaecomastia refers to benign excess of the male breast tissue, that is usually reversible. It is not a risk factor per se for developing male breast cancer.

Epidemiology

While it can occur at any age, it tends to have greater prevalence in two groups : adolescent boys and older men.

Pathology

In gynaecomastia, there is enlargement of the male breast due to benign ductal and stromal proliferation. A hallmark of gynecomastia is its central symmetric location under the nipple. Gynaecomastia in most cases tends to be unilateral and / or asymmetrical ³.

Causes

The causes of gynaecomastia are many and include

hormonal
- neonatal : maternal oestrogens
- pubertal : high oestradiol levels
- elderly : decline in testosterone levels
- hypogonadism / androgen deficiency states
  - Klinefelter syndrome
  - anorchism
  - testicular failure, e.g. testicular cancer
drugs
- diethylstilbestrol
- spironolactone
- thiazide diuretics
- digoxin
- anabolic steroids
- oestrogen treatment
- isoniazid
- ergotamine
- narcotics
  - marijuana
  - heroin
- cimetidine
- nifedipine
- reserpine
- methyldopa
- theophylline
systemic disorders
- advanced alcoholic cirrhosis
- haemodialysis in chronic renal failure
- chronic pulmonary disease, e.g. emphysema, tuberculosis
- malnutrition
tumours : particularly oestrogenic tumours
idiopathic

There can be three forms of gynaecomastia histologically

florid
intermediate
fibrotic

Gynaecomastia can be asymmetrical and at times even be unilateral.

Radiographic features

Mammography

May appear as an increased sub-areolar density, which may be flame-shaped.

Three mammographic patterns of gynecomastia have been described representing various degrees and stages of ductal and stromal proliferation. They are

nodular pattern
dendritic pattern
diffuse glandular pattern

Early nodular gynecomastia (florid phase) is seen in patients with gynecomastia for less than 1 year. At mammography, there is often a nodular subareolar density.

Chronic dendritic gynecomastia (quiescent phase) is seen in patients with gynecomastia for longer than 1 year. Fibrosis becomes the dominant process and is irreversible. Mammograms this phase typically show a dendritic subareolar density with posterior linear projections radiating into the surrounding tissue toward the upper-outer quadrant.

Diffuse glandular gynecomastia is commonly seen in patients receiving exogenous estrogen. Atmammography, there is enlargement of the breast and diffuse density with both dendritic and nodular features.

Breast ultrasound

Focal gynaecomastia can variably appear as a retroareolar, triangular, hypoechoic ( ~ 80%²) mass.

In early nodular gynecomastia there can be subareolar fan or disc shaped hypoechoic nodule surrounded by normal fatty tissue.

In diffuse glandular gynecomastia both nodular and dendritic features are seen surrounded by diffuse hyperechoic fibrous breast tissue.

In chronic dendritic gynecomastia, there is a often a subareolar hypoechoic lesion with an anechoic star-shaped posterior border, which can be described as fingerlike projections or "spider legs" insinuating into the surrounding echogenic fibrous breast tissue.