Cystic disease of the breast is such a common entity, especially in the decade preceding the menopause, that one wonders whether this is an expected process. The main consideration has always been its relationship to carcinoma of the breast.1 In 1940, Shields Warren2 stated, "The breast cancer attack rate for women with chronic mastitis and related lesions in the age group of from 30 to 49 years is 11.7 times the rate for the Massachusetts female population; in the group over 50 years of age, 2.5 times as great; in the entire group 4.5 times as great."
Others have taken a more conservative view. At Memorial Hospital in New York, they are conservative; so are Haagensen, Campbell,3 and others.
As a rule, most of the simple cysts and those showing only mild epithelial hyperplasia of one kind or another are handled conservatively, that is, by simple excision.