Cations and dehydroepiandrosterone-sulfate in cyst fluid of pre- and menopausal patients with gross cystic disease of the breast. Evidence for the existence of subpopulations of cysts.

Cations (K+ and Na+) content was evaluated in 444 breast cyst fluid (BCF) specimens, aspirated from 391 patients with gross cystic disease of the breast (GCD), a benign form admittedly at major risk of cancer. In 306/444 BCF, dehydroepiandrosterone-sulfate (DHA-S) content was also evaluated. A positive correlation (P less than 0.001) was observed between log K+ vs. log DHA-S whereas a negative correlation was found between log Na+ and log DHA-S (P less than 0.001). Cysts were subdivided in three types according to their cationic concentration: most were of type I (K+/Na+ greater than 1.5) and type II (K+/Na+ less than 0.66) whereas only 10% was of the type III (intermediate). No statistical difference in subtype distribution was apparent when considering patients aspirated in the follicular vs. luteal phase of the menstrual cycle; on the contrary, a significant difference (P less than 0.001) was found between menstruating vs. menopausal patients (type I = 54.8% vs. 32.2%; type II = 34.5% vs. 58.1%, respectively). Ninety-four BCF samples were aspirated simultaneously in 41 patients bearing multiple cysts: the same cationic subtype was present in 29/41 patients. Our data confirm and extend previous observations, and provide conclusive evidence that breast macrocysts can be divided on the basis of their electrolyte composition into different types. Accordingly, the composition of BCF should always be assessed for prospective studies on GCD and breast cancer risk.