Repeated aspiration of breast cysts--a safe procedure.

We have made a retrospective study of 197 patients who underwent 367 breast cyst aspirations and in whom the fluid obtained was sent for cytological examination between January 1974 and August 1976. Four specimens were reported as showing malignant cells in the aspirate. All of these were excised and 3 were confirmed to be malignant. A further 8 showed bizarre or atypical appearances, of which four were excised and 1 was malignant. The other 4 were subjected to repeat aspiration, at which time typical benign appearances were reported and no further action taken. No tumour developed in the follow-up period of at least 2 years. Of the patients whose initial cytology was benign, 51 were subjected to repeated aspiration of clinically recurrent cysts, 28 on 3 or more occasions. Ten patients underwent excision biopsy of histologically benign lesions. None of these 51 patients developed a malignant tumour at the site of the cyst in the 2-year follow-up period.