Atypia
Atypical ductal hyperplasia, ADH
Atypical lobular hyperplasia, ALH
It’s not uncommon for the lining of the ducts (carry milk to the nipple) and lobules (milk producing areas) to alter from a single layer of cells lining the inner surface to multiple layers and this benign process is called hyperplasia. Sometimes the cells may not only increase in number but they may become more irregular and start to divide abnormally. This change is called atypia. When it occurs in the milk duct it is called atypical ductal hyperplasia (ADH) and when it occurs in the lobule it is called atypical lobular hyperplasia (ALH).
When ADH or ALH is seen on a needle biopsy there is a chance that it may not represent the full pathological change in the area and, in 15-20 percent of cases, there may also be in situ or invasive malignancy present. For this reason when ADH or ALH is seen on needle biopsy open surgical biopsy is recommended. This usually involves a general anaesthetic and a small incision in the breast to remove a portion of the involved breast tissue to obtain a more accurate diagnosis.
If ADH or ALH only is seen on the open biopsy then no further treatment is required. For these women their risk of developing future breast cancer is increased by about two to four fold. As such further screening should include an annual mammogram, ideally combined with a breast ultrasound. Sometimes MRI screening is also a useful adjunct for these women.
If there is also a strong family history in a patient who has atypia, other strategies such as taking oestrogen blocking medications (Tamoxifen or aromatase inhibitors) or prophylactic mastectomy can sometimes be considered.
