Dear GardenAngel: Atypical ductal hyperplasia (ADH) is a condition in which there is an overgrowth of cells within the duct and the pattern of their growth is atypical. It is not cancer or precancer but its presence is considered to increase a person's risk for developing breast cancer in the future. The area of ADH is usually removed as a part of a biopsy and close follow-up (with mammography and breast exam) is the extent of treatment.
DCIS is a condition in which there are abnormal cells within the duct that do not yet show signs of invasion. DCIS is considered "precancerous" and is usually treated as a very early cancer. The treatment is generally surgical resection (either a lumpectomy or in some cases mastectomy) followed in some cases with radiation therapy. Hormone therapy may be recommended but chemotherapy is not necessary.
A margin refers to the edge of the specimen. When tissue is removed, the edges are inked so that the pathologist can look at the cells on the edges. If the abnormal cells are on or close to the edge, it is considered a close or positive margin. In these cases, additional treatment may be recommended, depending on the final pathology. Pathologists look at cells under a microscope to determine what they are. In some cases, differentiating to very similar conditions can be very difficult. In these cases, the slides may be sent to a second pathology department for another opinion (in some cases, these places may have expertise in certain conditions).