Gynecomastia can occur in a patient with Graves' disease (autoimmune thyroiditis).
Patient selection: male
Clinical features:
(1) presence of Graves' disease
(2) the patient develops gynecomastia, which may be unilateral or bilateral
(3) elevated serum sex hormone-binding globulin (SHBG)
(4) other causes of gynecomastia are excluded (unless mixed causation)
Graves' disease is associated with:
(1) an increase in the concentration sex hormone-binding globulin in the serum.
(2) increased peripheral conversion of androgens to estrogens
These result in an increased ratio of estrogens to androgens, which favors the occurrence of gynecomastia.
The patient may or may not be hyperthyroid.
Laboratory testing may show elevated serum estrogens, decreased serum LHm and decreased serum testosterone.
