D

DCIS: see ductal carcinoma in-situ entry.

Ductal Carcinoma in situ (DCIS): a form of pre invasive breast cancer, by definition confined to the breast as the cells have not yet penetrated the natural membrane (basement membrane) around the cells. DCIS per se is therefore unlikely to spread to distant organs, and is completely curable. Prior to the National Health Breast Screening Programme (NHSBSP) in the United Kingdom, DCIS formed less than 5% of all breast malignancies. This is because DCIS alone does not usually form a lump, although with larger areas of involvement 5% or so of cases of DCIS can form a lump. With the NHSBSP, DCIS now forms 30% of all breast cancers. Most DCIS presents with microcalcification, and is detected on mammography (see entry). Indeterminate (M3), suspicious (M4), and microcalcification diagnostic of carcinoma (M5) (see mammography entry) require further investigation and core cut biopsy (see entry). Histopathologically, DCIS can be classified as low (grade I), intermediate (grade II) or high grade (III), each respectively more aggressive in subtype. The presence of necrosis (areas of cell death and debris) on microscopic examination also contribute to aggressive type. Other microscopic variants are termed cribriform, solid and papillary. Localised DCIS can be treated by wide local excision (see entry), usually after wire localisation (see entry). Low grade and intermediate grade DCIS involving a small area, say less than 15 mm, that is completely excised (for example, by a margin in excess of 1 cm) may be treated by surgery alone with or without adjuvant breast radiotherapy. Women with small areas of high grade DCIS treated by breast conservation should be offered adjuvant radiotherapy to the breast. Large areas of DCIS, say larger, than 40mm that is not completely excised may be better treated by mastectomy, though may vary with other factors such as size of the breast and multifocal disease. There is usually no indication for radiotherapy after mastectomy for DCIS. The role of tamoxifen as adjuvant therapy for DCIS remains controversial.

Duct ectasia: a benign condition that may lead to nipple discharge in pre and post-menopausal women. The major ducts, that form the end portions of the milk producing system of the breast, are situated behind the nipple. Most women have 15 to 20 major ducts. The aetiology of duct ectasia is not certain, but is likely to be a variant within the normal spectrum. Normal breast cell secretion is absorbed in normal ducts; thus no excess fluid forms to become clinically significant nipple discharge. The supporting structure of the ducts can become leaky resulting in a localised inflammation around the ducts. Healing by scar contracture can lead to a characteristic indrawing of the nipple in the form of a transverse slit appearance. Duct ectasia and a related condition called periductal mastitis (see entry) can lead to abscess formation in extreme cases.

Duct papilloma: a benign small wart-like growth within the breast ducts. These can be single or multiple, and located anywhere within the breast. More central lesions can lead to blood stained nipple discharge. Papillomas of the breast are generally benign. Duct papillomas of the solitary central type carry no increased breast cancer risk but other forms may have an associated breast cancer risk that requires follow-up.