[tribal]

Gynecomastia Development Continued

The gynecomastia of liver disease, particularly cirrhosis, does not have a clear etiology. Some have speculated that the gynecomastia is the result of estrogen overproduction, possibly secondary to increased extraglandular aromatization of androstenedione, which may have decreased hepatic clearance in cirrhotics. However, testosterone administration to cirrhotics causes a rise in estradiol, but decreases the prevalence of gynecomastia (13, 3, 37). Therefore, although the association of gynecomastia with liver disease is apparent, current data are conflicting and the mechanism by which this occurs remains unclear.

As previously stated, thyrotoxicosis is associated with gynecomastia. Patients often have elevated estrogen that may result from a stimulatory effect of thyroid hormone on peripheral aromatase. Testosterone may also be increased possibly due to thyroid-hormone-stimulated increase in SHBG, as free testosterone is usually normal. Since SHBG binds testosterone more avidly than estradiol, there is a higher ratio of free estradiol to free testosterone. Thus, with normal testosterone and increased estrogen, there is an elevated estrogen to testosterone ratio. In addition, LH is also increased, which may also stimulate testicular estrogen synthesis (18, 10).

Gynecomastia can also follow spinal cord disorders. Most patients with spinal cord disorders display depressed testosterone levels and, in fact, can develop testicular atrophy with resultant hypogonadism and infertility. Some have speculated that this may result from recurrent urinary tract infections, increased scrotal temperature, and a neuropathic bladder, which ultimately cause acquired primary testicular failure. The exact mechanism, however, remains elusive (19).

Refeeding gynecomastia refers to breast development in men recovering from a malnourished state (15). Although most cases regress within seven months, the etiology of this phenomenon has not been fully elucidated.

HIV patients can also develop gynecomastia. There is a high incidence of androgen deficiency due to multifactorial causes, including primary and secondary hypogonadism (30).

DRUGS

A significant percentage of gynecomastia is caused by medications or exogenous chemicals that result in increased estrogen effect. This may occur by several mechanisms: 1) they possess intrinsic estrogen-like properties, 2) they increase endogenous estrogen production, or 3) they supply an excess of an estrogen precursor (e.g. testosterone or androstenedione) which can be aromatized to estrogen. Examples of drugs that cause gynecomastia are listed in Tables 2 and 3. Contact with estrogen vaginal creams, for instance, can elevate circulating estrogen levels. These may or may not be detected by standard estrogenic qualitative assays. An estrogen-containing embalming cream has been reported to cause gynecomastia in morticians (4, 14). Recreational use of marijuana, a phytoestrogen, has also been associated with gynecomastia. It has been suggested that digitalis causes gynecomastia due to its ability to bind to estrogen receptors (18, 39). The appearance of gynecomastia has been described in body builders and athletes after the administration of aromatizable androgens. The gynecomastia was presumably caused by an excess of circulating estrogens due to the conversion of androgens to estrogen by peripheral aromatase enzymes (9).

Drugs and chemicals that cause decreased testosterone levels either by causing direct testicular damage, by blocking testosterone synthesis, or by blocking androgen action can produce gynecomastia. For instance, phenothrin, a chemical component in delousing agents, possessing antiandrogenic activity, has been attributed as the cause of an epidemic of gynaecomastia among Haitian refugees in US detention centers in 1981 and 1982 (8). Chemotherapeutic drugs, such as alkylating agents, cause Leydig cell and germ cell damage, resulting in primary hypogonadism. Flutamide, an anti-androgen used as treatment for prostate cancer, blocks androgen action in peripheral tissues, while cimetidine blocks androgen receptors. Ketoconazole, on the other hand, can inhibit steroidogenic enzymes required for testosterone synthesis. Spironolactone causes gynecomastia by several mechanisms. Like ketoconazole, it can block androgen production by inhibiting enzymes in the testosterone synthetic pathway (i.e. 17a hydroxylase and 17-20-desmolase), but it can also block receptor-binding of testosterone and dihydrotestosterone (45). In addition to decreasing testosterone levels and biologic effects, spironolactone also displaces estradiol from SHBG, increasing free estrogen levels. Ethanol increases the estrogen to androgen ratio and induces gynecomastia by multiple mechanisms as well. Firstly, it is associated with increased SHBG, which decreases free testosterone levels. Secondly, it increases hepatic clearance of testosterone, and thirdly, it has a direct toxic effect on the testes themselves (30). Unfortunately, besides the drugs stated, a multitude of others cause gynecomastia by unknown mechanisms (Table 3).

MALE BREAST CANCER

Male breast cancer is rare and comprises only 0.2 percent of all male cancers. Although uncommon, it has been associated with gynecomastia and necessitates inclusion in the differential diagnosis. Other risks include Klinefelter's syndrome, exogenous estrogen exposure, family history, and testicular disorders. It is unclear if these are specific risks for breast cancer are linked to the stimulatory process responsible for gynecomastia. New evidence suggests obesity and consumption of red meat may also raise the risk for the development of male breast cancer (21).

PATIENT EVALUATION

HISTORY AND PHYSICAL EXAMINATION

At presentation, all patients require a thorough history and physical exam. Particular attention should be given to medications, drug and alcohol abuse, as well as other chemical exposures. Symptoms of underlying systemic illness, such as hyperthyroidism, liver disease, or renal failure should be sought. Furthermore, the clinician must recall neoplasm as a possible etiology and should establish the duration and timing of breast development. Obviously, rapid breast growth that has occurred recently is more concerning than chronic gynecomastia. Additionally, the clinician should inquire about fertility, erectile dysfunction and libido to rule out hypogonadism, either primary or secondary, as a potential cause.

In our experience, the breast examination is best performed with the patient supine and with the examiner palpating from the periphery to the areola. The glandular mass should be measured in diameter. Gynecomastia is diagnosed by finding subareolar breast tissue of 2 cm in diameter or greater. Malignancy is suspected if an immobile firm mass is found on physical examination. Skin dimpling, nipple retraction or discharge, and axillary lymphadenopathy further support malignancy as a possible diagnosis.

A thorough testicular exam is essential. Bilaterally small testes imply testicular failure, while asymmetric testes or a testicular mass suggest the possibility of neoplasm. Visual field impairment may suggest pituitary disease. Physical findings of underlying systemic conditions such as thyrotoxicosis, HIV disease, liver, or kidney failure should also be assessed.

LABORATORY EVALUATION

All patients who present with gynecomastia should have serum testosterone, estradiol, LH and b HCG measured. Further testing should be tailored according to the history, physical examination and the results of these initial tests. An elevated b HCG or a markedly elevated serum estradiol suggests neoplasm and a testicular ultrasound is warranted to identify a testicular tumor, keeping in mind, however, that other non-testicular tumors can also secrete b HCG. A low testosterone level, with an elevated LH and normal to high estrogen level indicates primary hypogonadism. If the history suggests Klinefelter's Syndrome, then a karyotype should be performed for definitive diagnosis. Low testosterone, low LH and normal estradiol levels imply secondary hypogonadism, and hypothalamic or pituitary causes should be sought. If testosterone, LH and estradiol levels are all elevated, then the diagnosis of androgen resistance should be entertained. Liver, kidney and thyroid function should be assessed if the physical examination suggests liver failure, kidney failure, or hyperthyroidism, respectively. Furthermore, if examination of breast tissue suggests malignancy, a biopsy should be performed. This is of particular importance in patients with Klinefelter's syndrome, who have an increased risk of breast cancer.

TREATMENT

Treatment of the underlying endocrinologic or systemic disease that has caused gynecomastia is mandatory. Testicular tumors, such as Leydig cell, Sertoli cell or granulosa cell tumors should be surgically removed. In addition to surgery, germ cell tumors are further managed with chemotherapy involving cisplatin, bleomycin and either vinblastine or etoposide (38, 16). Should underlying thyrotoxicosis, renal or hepatic failure be discovered, appropriate therapy should be initiated. Medications that cause gynecomastia should also be discontinued whenever possible based on their role in management of the underlying condition. Of course, if a breast biopsy indicates malignancy, then mastectomy should be performed.

If no pathologic abnormality is detected, then appropriate treatment is close observation. A careful breast exam should be done initially every 3 months until the gynecomastia regresses or stabilizes, after which a breast exam can be performed yearly. It is important to remember that some cases of gynecomastia, especially that which occurs in pubertal boys, can resolve spontaneously.