The presentation and progress of macroscopic breast cysts.

A total of 322 cases of macroscopic breast cysts presenting at a district general hospital has been studied with a minimum follow-up period of 5 years. In almost half the patients (44.18 per cent) a further cyst occurred following aspiration, and in two-thirds of these, more than one subsequent cyst developed. There was a 50-year age span from the youngest to the oldest patient at presentation: however, the majority of cysts (61.80 per cent) occurred in the perimenopausal age group (40-50 years). The subsequent incidence of carcinoma was more than twice that which would be expected in the population at large, but no case of carcinoma that was not suspected clinically was revealed by cytology.