Gross cystic disease of the breast.

The aetiology of fibrocystic disease of the human breast remains problematical. While oestrogens may cause cystic lesions and epithelial proliferation in the mammary glands of experimental animals and certain progestogens (chlormadinone acetate and medroxyprogesterone acetate) may induce severe myoepithelial hyperplasia in beagles, the classical oral contraceptives (oestrogens and progestogens) reduce the incidence of fibrocystic breast disease in women. The role of prolactin in human breast disease is far from clear despite the fact that in rodents mammary tumors fail to develop following oestrogen administration in the absence of prolactin. Because women with gross cystic disease of the breast are at four times greater risk of developing malignant breast disease, it is felt that the administration of courses of danazol, an impeded androgen derived from the progestin, 17 alpha-ethinyl testosterone, has proved effective in lessening fibrocystic disease of the breast, frequently obviating the need for breast biopsy. The study of the hormonal content of fluid aspirated from gross breast cysts should help elucidate the pathophysiology of breast disease. Breast cyst fluid is rich in androgens, particularly dehydroepiandrosterone sulfate; concentrations of polypeptide hormones like FSH, LH, TSH, PRL, and calcitonin are invariably present sometimes in less and at other times in greater amounts than that found in plasma. Of particular interest is the finding of measurable levels of beta-hCG in cyst fluid but not in the serum. The question arises whether the beta-hCG is biologically active or are the assay values merely the expression of radioimmunoassayable components? Preliminary (as yet unpublished) studies reveal excellent bioactivity as measured by testosterone production in Leydig cell cultures. Time will tell whether elevated levels of bioactive beta-hCG portend neoplastic potential.