[Diagnosis of (intra)-cystic breast cancer].

Besides the known intracystic carcinoma of the breast there are also other cystic tumour types such as, for example, the cystically necrotized carcinoma of the mamma. Preoperative diagnosis of these tumours is effected via pneumocystography and aspiration cytology if mammography alone does not yet permit a definitive assessment of the tumour status. If sonography is used as the only additional examination, diagnostic errors are likely to happen. The well-known recommendation according to which sonographically identified ("simple") cysts can be left as they are, deserves further discussion under this aspect. The problems associated with histological classification and preoperative diagnosis are discussed taking five cystic carcinomas of the breast as basis.