Benign breast disease in Nigerian women: a study of 657 patients.

A 15-year combined retrospective (222 patients) and prospective (435 patients) evaluation of the pattern of benign breast disease in one region of the African tropics has been completed. Fibroadenoma constituted the largest group (55.6%), followed by mammary dysplasia (fibrocystic disease with fibroadenosis: 29.3%) and sclerosing adenosis (7.9%). Approximately one-third of women were under 20 years and two-thirds under 25. For the 435 patients in the prospective study, a late mean [SEM] age at menarche of 15.3 (2.1) years (controls: 14.2 [2.5], NS; early first full-term pregnancy: 20.4 [1.6] years, (controls: 21.1 [1.1], NS; parity 3.6 [1.7], (controls: 4.1), NS; and prolonged breast feeding (17.6 [2.2] months) did not appear to constitute risk factors to the development of benign breast disease among Nigerian women.