Anatomy of Gynecomastia
Causes of Gynecomastia
Diagnosis of Gynecomastia
History of gynecomastia treatment
Treatment of gynecomastia


Whenever the physician is faced with a patient complaint, his/her task is to formulate a "differential diagnosis." Differential diagnosis involves making a list of possible diagnoses based upon the presenting complaint, and then attempting to remove diagnoses from the list until only one remains. As can be seen with a review of the "Causes" section of this site, the list of conditions giving rise to gynecomastia is fairly long. However, the majority of cases are actually produced by just a few conditions among those listed, and happily, it is often easy to discern the diagnosis in these cases based simply on the history and physical examination.

Physiological Gynecomastia

A newborn baby with breast development, or a boy in his young teens with tender plaques behind the areolae needn't routinely be put through significant workups. If the remainder of the physical exam is normal in each case, expectancy is indicated.


If a teenage boy has gynecomastia that persists, is severe in degree, or if there are other signs on exam of feminization, some endocrine evaluation is justified. Standardly ordered blood tests would include:

  • HCG (human chorionic gonadotropin)
  • LH (luteinizing hormone)
  • TSH (thyroid stimulating hormone)
  • T3/T4 (thyroid hormone levels)
  • Estradiol
  • Testosterone

Where there is evidence of "hypogonadism," (low testosterone), a testicular ultrasound is warranted in search of a mass, and a sex chromatin study can be done to rule out Klinefelter's syndrome. (Boys with Klinefelter's Syndrome have an extra "X"-female chromosome and are more likely to have gynecomastia than the normal male population). If there are elevated levels of estradiol in the urine, and this is accompanied by high levels of 17-keto-steroid, this should prompt a scan of the adrenals in search of a feminizing tumor.

The great majority of young boys with gynecomastia who are tested as described will have normal findings. In those who don't a useful algorithm is provided.

Hormone workup

Other Tests

Where hormonal assays are normal, it may be well to perform liver and renal function tests. One should test for the presence of hyperlipidemia, hyperglycemia, and insulin resistance in order to exclude diabetes-related breast changes.

Imaging Studies

Ultrasound of the breast and mammogram can be very useful in helping to determine the makeup of the tissue involved in breast enlargement. It is particularly important to perform imaging in cases that do not fit the description of adolescent physiological gynecomastia, and in those that are markedly unilateral. An important principal worth remembering is that gynecomastia, no matter what its radiographic pattern, is always a subareolar mass. Radiographic masses that are not centered behind the areola are not gynecomastias, and need further workup. Among the lesions of the male breast to be excluded are:

  • Adenoma
  • Cystic lymphangioma
  • Diabetic mastopathy
  • Epithelial inclusion cyst
  • Fibrocystic changes
  • Granular cell tumor
  • Leiomyoma
  • Lipoma
  • Myofibroblastoma
  • Papilloma
  • Pleomorphic hyalinizing angioectatic tumor of soft parts

Naturally, any new breast mass in a man without history consistent with physiologic or drug-related gynecomastia must be worked up to exclude malignancy as well. Among the cancers seen in the male breast are:

  • Infiltrating ductal carcinoma
  • Liposarcoma
  • Lymphoma
  • Metastatic cancer (spread from elsewhere)

Although mammography has been widely used in the assessment of the male breast, it has been replaced in many institutions by ultrasonography as a first-line investigation. With ultrasound that employs high-frequency, linear-array transducers, normal breast tissue can be easily identified as an ill-defined, echo-poor area of nodularity deep to the nipple. ultrasound of gynecomastia Any discrete echo-poor nodule with increased vascularity or acoustic shadowing should be considered suspicious for malignancy and prompt guided tissue sampling using fine-needle aspiration or Tru-Cut biopsy. see histology

Male Breast Cancer

Breast cancer in men accounts for approximately 1% of all breast cancers. People from Africa and China have higher incidence of the disease, likely the result of hyper-estrogenism produced by liver parasites common to those locations. Also, those with Klinefelter's Syndrome, (XXY), undescended testes, history of orchitis or testicular cancer are at greater risk.

As in females, those with family history of breast cancer are at greater risk, and the BRCA 2 gene is seen in 4-16 % of men with breast cancer. The disease is more common with advancing age and seen more commonly in those of Jewish background or exposure to hepatotoxins. Curiously, there is a higher incidence of this cancer among those who worked in the steel industry and sustained occupational exposure to high heat.

The classic presentation is that of a unilateral, painless sub-areolar mass. It can be accompanied by bloody nipple discharge, which is not seen with gynecomastia. Most cancers are invasive ductal carcinomas. Ductal carcinoma in-situ (DCIS) is rare since screening programs that might discover early disease are non-existent for men.

Definitive diagnosis for a new, unilateral breast mass demands needle or open surgical biopsy. As in women, carcinomas treated in the earlier stages, (before spread to lymphatics), have a much better prognosis. (See the Gallery for images.)

Gynecomastia and HIV Therapy

Gynecomastia has been shown to be strongly related to use of the anti-retroviral drugs employed in the treatment of HIV disease. This is particularly the case with protease inhibitor-based therapies. Both true, glandular gynecomastia, and lipomastia (pseuodgynecomastia, or "fatty" gynecomastia), appear to be more frequent. The latter may be considered a part of the lipodystrophy syndrome seen among patients given highly active antiretroviral therapy, (HAART). This syndrome can include lipoatrophy of the face, limbs, and buttocks, abdominal fat accumulation, wasting syndrome and multiple lipomatosis.

Patients with gynecomastia may be entirely asymptomatic, but some present with tenderness and discomfort. As in any other case, it is important to exclude other causes for gynecomastia (as above) before implicating the anti-retroviral agents. Of particular note is the fact that those who are immunologically compromised are at greater risk for both granulomatous disease and lymphomas of the breast, both of which should be carefully excluded.

Anti-retroviral gynecomastias develop more often in those with good immunological status, and usually are seen after several years of therapy. Initial presentation is often unilateral, but most progress to bilateral involvement. Since spontaneous resolution will occur within a year for many patients, surgical treatment should be reserved for recalcitrant cases. (See Treatment )