F ibroadenomas are common benign lesions of the breast that usually present as a single breast mass in young women. They are assumed to be aberrations of normal breast development or the product of hyperplastic processes, rather than true neoplasms. The clinician often faces the dilemma whether to remove the mass or to monitor it by means of periodic follow-up examinations. Although removal of these lesions is a definitive solution, surgery may involve unnecessary excisions of benign lesions and unbecoming cosmesis. Moreover, a policy of conducting surgery on all patients with fibroadenomas would place an enormous burden on health care systems. A balanced and rational approach to the management of a fibroadenoma of the breast needs to address the crucial questions about its association with breast cancer, especially whether or not it is a marker of increased risk of breast malignancy. Another consideration to be weighed is that a substantial percentage of these lesions undergo spontaneous regression. Herein, based on our review of the current data on fibroadenomas of the breast and our experience, we propose practical algorithms for their management.
INCIDENCE AND RISK FACTORSThere are no clear-cut data on the incidence of fibroadenomas in the general population. In one study, the rate of occurrence of fibroadenomas in women who were examined in breast clinics was 7% to 13%, 1 while it was 9% in another study of autopsies. 2 Fibroadenomas comprise about 50% of all breast biopsies, and this rate rises to 75% for biopsies in women under the age of 20 years. 3,4 Fibroadenomas are more frequent among women in higher socioeconomic classes 5-7 and in dark-skinned populations. 8 The age of menarche, the age of menopause, and hormonal therapy, including oral contraceptives, were shown not to alter the risk of these lesions. 6,7,9,10 Conversely, body mass index and the number of full-term pregnancies were found to have a negative correlation with the risk of fibroadenomas. [5][6][7]9,11 Moreover, consumption of large quantities of vitamin C and cigarette smoking were found to be associated with reduced risk of a fibroadenoma. 7,12,13 No genetics factors are known to alter the risk of fibroadenoma. However, a family history of breast cancer in firstdegree relatives was reported by some investigators to be related with increased risk of developing these tumors. 14,15
PATHOLOGYFibroadenomas usually form during menarche (15-25 years of age), a time at which lobular structures are added to the ductal system of the breast (Fig. 1). Hyperplastic lobules are common at that time, and may be regarded as a normal phase of breast development. 16 Hyperplastic lobules were shown to be histologically identical with fibroadenomas. 10,17 Analyses of the cellular components of fibroadenomas by means of polymerase chain reaction demonstrated that both the stromal and the epithelial cells are polyclonal, 18 supporting the theory that fibroadenomas are hyperplastic lesions associated with aberration of the normal maturation of the breast, ra...
