Endocrine Abstracts

Most cases of gynecomastia are idiopathic. Among the most frequently identified etiologies are: persistent pubertal gynecomastia, hypogonadism, anabolic steroids and other pharmaceutical drugs use. In the literature, ginecomastia is a well-recognized manifestation of thyrotoxicosis in male patients (in the range of 10% to 40%). However, it is extremely rare in clinical practice as the initial presentation of thyrotoxicosis. The two main factors that contribute to gynecomastia in thyrotoxicosis are: increase of SHBG production in the liver (which leads to a reduction in free testosterone); and increased peripheral aromatization of androgens. We report a case of a 41-year-old white male who applied to our clinic with a 2 weeks history of right-sided breast enlargement. He did not report reduced libido. No past medical history or drug intake were reported. On examination he was normotensive and had normal-weight. Glandular tissue could be palpated on the right breast, underneath the nipple area. Galactorrhoea was not observed. Cervical palpation was normal. The testicles had a normal size and no palpable abnormalities were found. Laboratory data showed testosterone level of 1116 ng/dl (241-827), free testosterone level of 24 pg/ml (8.69-54.69), estradiol level of 51 pg/ml (<32), SHBG of 107 nmol/l (10-57), LH 7.46 mUI/ml (1.5-9.3), FSH 7.68 mUI/ml (1.4-18), TSH <0.01 mUI/l (0.35–5.5), free T4 (FT4) 2.16 ng/dl (0.8–1.76) and free T3 (FT3) 7.52 pg/ml (2.3-4.2). Anti-TSH receptor antibodies values were 2.47 UI/l (<1). Levels of prolactin, alpha-fetoprotein, human chorionic gonadotropin, dehydroepiandrosterone sulfate were normal. An ultrasound examination revealed a thyroid gland diffusely heterogeneous, without nodularity. The diagnosis of Graves′ disease was made. He was treated with thiamazole 15 mg daily. After 1 month from the start of treatment, gynecomastia had resolved. The monthly follow-up laboratory findings showed normalization of FT3 and FT4. SHBG and total testosterone levels decreased significantly after 2 months and free testosterone increased. GD may present with atypical symptoms and the classic symptoms of thyrotoxicosis may not always be in the foreground. In case of gynecomastia, thyrotoxicosis should be kept in mind. An attentive diagnosis may identify a potentially treatable cause of gynecomastia.