Nipple discharge alone tends to be a relatively uncommon presenting complaint, but it may be associated with a breast lump and requires prompt assessment. Discharge may be bloody, coloured opalescent, or milky. Duct ectasia or epithelial hyperplasia are the commonest benign causes of nipple discharge.
The major subareolar ducts dilate and shorten during involution, and by the age of 70, 40% of women have substantial duct dilation or duct ectasia. Some women with excessive shortening and dilation develop nipple discharge, nipple retraction, or a palpable mass or abscess formation. Typically the discharge arises from multiple rather than single ducts. Although the appearances may be mistaken for cancer, duct ectasia per se is not associated with increased risk of malignancy.
Epithelial duct hyperplasia is a benign condition where there is an increase in the number of cells that line the lobular duct unit of the breast.
If the cells also appear abnormal, the condition is called atypical hyperplasia and is associated with an increased risk of breast cancer, of the order of 8% at 10 years, if there is no family history. Epithelial hyperplasia may also be associated with benign polyp-like growth called papilloma, which can present with bloody nipple discharge arising from a single duct of the breast. There may also be a palpable nodule below the skin, which, upon pressure, results in the release of discharge. Benign papillomas are very common and are of low malignant potential. However, the risk of these disorders being associated with an invasive cancer increases with age, particularly in postmenopausal women, and invasive malignancy should be excluded.
Galactorrhoea is the production of milk from the breast, which is unrelated to breast-feeding. The cause of this is usually physiological, but it may be related to the intake of certain drugs, such as the phenothiazines, or metoclopramide. Rarely, galactorrhoea is due to increased production of prolactin from a pituitary tumour.
Treatment of Nipple discharge
The management of nipple discharge depends on the underlying cause and age of the patient. Galactorrhoea can be treated with bromocriptine if it is excessive and the underlying cause has been identified and managed appropriately. Blood-stained discharge in women under the age of 40 years is rarely associated with cancer, but malignancy should be excluded. In older women, the risk of malignancy is much higher and the affected ducts should be excised. Sometimes antibiotics can help in duct ectasia, particularly if there is an inflammatory component. Occasionally surgery is required if the volume of discharge is sufficient to require the use of pads for symptom relief, once a more serious underlying cause has been excluded.