Endocrine Abstracts

Gynecomastia is an uncommon clinical manifestation of hyperthyroidism, due to an imbalance between sexual hormones caused by thyroid hormones excess. Recognition of such unusual association is important to ensure appropriate treatment and to avoid unnecessary investigation. In hyperthyroidism, increased serum levels of SHBG binds testosterone with greater affinity than estradiol, resulting in relatively higher free estradiol compared with free testosterone levels and thereby contributing to stimulation of breast tissue and gynecomastia. A 52-year-old man with no medical history was referred to endocrinology department because of painful enlargement of his breasts. He also complains about palpitations, tremor and 10 kg weight loss in the last 3 months. The patient was not from endemic area for goiter and had no family history of thyroid disease. Physical examination revealed enlarged thyroid, tremor of both hands, tachycardia (110/min), painful breasts enlargement with about 2 cm of palpable tissue. Laboratory findings revealed hyperthyroidism with high levels of anti TSH antibodies. The patient was treated with methimazole 30 mg daily and b-adrenergic blocking agent with rapid improvement of symptoms and significant regression of gynecomastia in less than a month.