Fibroadenomas in Patients Receiving Oral Contraceptives: A Clinical and Pathologic Study

54 fibroadenomas excised from women receiving oral contraceptives were compared with 54 fibroadenomas removed from other women before the availability of the pill. The specific pill preparations for 24 of the patients who used oral contraception were known: 21 combination formulas and 3 sequential formulas. The ratio of fibroadenomas to other lesions of the breast has been nearly the same in the oral contraceptive era (17.1%) as it was in the 5-year control period immediately preceding the availability of oral contraceptives (17.4%). Except for 4 tumors with acinar proliferation similar to that seen in fibroadenomas removed during pregnancy or lactation (rarely in nonpregnant patients) the gross and microscopic features of the fibroadenomas from contraceptive patients were qualitatively indistinguishable from those of control tumors. It is suggested that the patient with a fibroadenoma which appears during contraceptive use is the patient already predisposed to this condition and who might develop the condition without the pill. It is possible that the pill stimulates a preexisting lesion to grow and become clinically detectable earlier.