A high risk lesion refers to a lesion that has, or is associated with, a greater risk of developing breast cancer in future, or that suggests a more concerning underlying pathology. While these lesions are not breast cancer, excision is often recommended.
Atypical ductal hyperplasia (ADH)
This is a pathological term that describes the appearance of atypical cells in the milk ducts under a microscope. The cells in the duct will appear as though they are abnormal or atypical. There is an overgrowth of the cells lining the milk ducts of the breast that shows abnormal cellular characteristics.
It shares many characteristics with ductal carcinoma in situ (DCIS), and diagnosis is based on biopsy. Due to its potential to develop into an invasive cancer, and the similarities to DCIS, surgical excision is generally advised.
The diagnosis of atypical ductal hyperplasia at excisional biopsy puts the patient into a higher risk category for developing breast cancer in the future (around 10% within 10 years). This can also increase the risk of contralateral breast cancer (breast cancer in the opposite breast to one where the ADH was found).
Lobular breast neoplasia
Atypical lobular hyperplasia (ALH)
Atypical lobular hyperplasia refers to an overgrowth of the cells within the lobules, or milk-producing glandular tissue, of the breast, whereby the cells show abnormal characteristics. It is a mild breast lesion that is associated with an increased risk of future development of breast cancer, roughly 4-6 times the normal risk.
ALH usually does not produce changes on examination of the breast and is usually not seen on mammography. It is often found incidentally on biopsies performed for other reasons. If it is found on a core biopsy an excisional biopsy will usually be recommended. Typically no further treatment is required although regular monitoring of the breasts should be performed due to the increased risk of breast cancer.
Lobular carcinoma in situ (LCIS)
Lobular carcinoma in situ (LCIS) occurs when abnormal cells are contained within the lobules of the breast, but is not a form of true breast cancer (despite the word “carcinoma”). LCIS most often develops in women in their forties and fifties, usually before menopause. It is typically diagnosed incidentally on a biopsy performed for another reason, as it does not produce changes on mammography.
Women who develop LCIS have an increased risk of developing breast cancer in the future, although, still, the majority will not develop breast cancer. Monitoring, rather than treatment, is often indicated, unless treatment is selected to reduce the risk of breast cancer. Monitoring is performed through regular mammograms and other types of breast imaging.
Radial scarring/Complex sclerosing lesion
A radial scar, or complex sclerosing lesion, may be found on mammography or occasionally felt on examination, and refers to a benign, non-cancerous breast lesion. Its significance is in its ability to mimic the appearance of breast cancer on mammography. It is unrelated to surgical scarring.
Due to the similarity of its appearance to breast cancer, it is often excised surgically, although close monitoring following a clear biopsy may also be considered. It has a mild association with DCIS and some invasive tumours, and in general slightly increases the risk of future breast cancer development.