Gynecomastia (Gm) is defined as increased mammary gland size in male and must be distinguished from lipomastia. Mammary tissue is present in children of both sexes. The gland does not develop when androgens (A) prevail over estrogens (E). In men molar ratio of plasma testosterone to estradiol is about 300 to 1. Any deviation from this ratio, be it through diminished A or increased E, can lead to Gm. Testes maturation requires both A and E and palpable mammary tissue is present in about 40% of pubescent boys that disappears within 23 years (adolescent Gm). It may occasionally be persist until adulthood (persistent adolescent Gm) without clinical significance, except for psychogenic discomfort. Gm may appear in ageing male. In any age, Gm may indicate tumor with supranormal E secretion. Leydigyoma, embryonic carcinoma, teratocarcinoma, chorioncarcinoma and bronchial carcinoma lead either directly or via elevated hCG secretion to increased E production by Leydig cells. Palpation and ultrasound of testes are obligatory. Gm may associate congenital adrenal hyperplasia and adrenal tumors. Klinefelter syndrome, other primary or secondary hypogonadisms, diseases of androgen target organs (Reifenstein syndrome, perineal hypospadias, intersexuality), liver cirrhosis, terminal renal failure may be associated with Gm. In thyrotoxicosis, Gm result from increased production of sex hormone binding globulin and decreased bioavailability of A. In large unilateral Gm mammography is needed for diagnosis of a possible mammary cancer (1% of all breast cancers). Different drugs (including anti-androgens) may induce or exacerbate Gm. In 50% of cases idiopathic Gm is diagnosed. Recently CYP19 gene polymorphism with high aromatase activity has been attributed to incidence of Gm. Therapy should target underlying cause. In idiopathic Gm an anti-estrogen tamoxifen (10 mg b.i.d.) is suggested. If, after 3 months of treatment no improvement has occurred or if patient desires primarily a surgical correction, gynecomastectomy is advocated.
25 - 29 Apr 2009
European Society of Endocrinology