Drugs such as digoxin, marijuana, alcohol, spironolactone, cimetidine, metoclopramide, alkylating agents and other antitumor drugs, and psychotropics have all been implicated as causes. Gynecomastia in these circumstances is usually more annoying than significant. If it is accompanied by erectile dysfunction or by lowering of the plasma testosterone level, further study and perhaps discontinuance of the drug are in order. Occasionally, progressive gynecomastia is the clue to an underlying neoplasm. Tumors of the adrenal gland and testis may induce a disproportionate secretion of estrogen and thereby cause gynecomastia.
Patients usually have an increased plasma estradiol level and a low or normal gonadotropin level.
Estradiol, however, is so potent that significant gynecomastia can develop without elevation of the plasma estradiol level. Ectopic production of hCG by malignant tumors is occasionally accompanied by gynecomastia. The combination of recent gynecomastia with elevated estrogen and hCG titers should prompt a search for a primary tumor. Although the finding of hCG in the plasma of normal people has thickened the plot, high hCG titers and dynamic studies can be used to identify a tumor as the probable cause. The treatment of gynecomastia depends on its cause and course.