Cystic tumours of the breast.

A retrospective survey of cystic tumours of the breast seen at the North Middlesex and St Bartholomew's Hospitals, London, has been undertaken to determine their incidence and clinical features. During the years 1967-76 4530 histological examinations were carried out on breast tissue and 1277 breast cancers diagnosed. Intracystic papillary tumours, both benign and malignant, were the least uncommon of cyst tumours, but the malignant type accounted for 0.55% of all the breast cancers. Aspects suggesting the possible presence of an intracystic tumour are discussed.