Mammary ductal carcinoma overview

Overview
Mammary ductal carcinoma is the most common type of breast cancer in women. It comes in two forms: infiltrating ductal carcinoma (IDC), an invasive, malignant and abnormal proliferation of neoplastic cells in the breast tissue and ductal carcinoma in situ (DCIS), a noninvasive, possibly malignant neoplasm that is still confined to the lactiferous ducts, where breast cancer most often originates.

Intraductal carcinoma
Intraductal carcinoma of the breast (Ductal Carcinoma In Situ, DCIS) is the most common type of noninvasive breast cancer in women. Ductal carcinoma refers to the development of cancer cells within the milk ducts of the breast. In situ means "in place" and refers to the fact that the cancer has not moved out of the duct and into any surrounding tissue.

As screening mammography has become more widespread, DCIS has become one of the most commonly diagnosed breast conditions, now accounting for 20% of screening detected breast cancer. It is often referred to as "stage zero breast cancer." In countries where screening mammography is uncommon, DCIS is sometimes diagnosed at a later stage, but in countries where screening mammography is widespread, it is usually diagnosed on a mammogram when it is so small that it has not yet formed a palpable lump. DCIS is not traditionally regarded as being harmful in itself, however there is evidence of metastases in up 2% of cases of DCIS. DCIS is usually discovered through a mammogram as very small specks of calcium known as microcalcifications. However, not all microcalcifications indicate the presence of DCIS, which must be confirmed by biopsy. DCIS may be multifocal, and treatment is aimed at excising all of the abnormal duct elements, leaving "clear margins", an area of much debate. After excision treatment often includes local radiation therapy. With appropriate treatment, DCIS is unlikely to develop into invasive cancer. Surgical excision with radiation lowers the risk that the DCIS will recur or that invasive breast cancer will develop.

Invasive Ductal Carcinoma
Invasive Ductal Carcinoma (IDC) is the most common form of invasive breast cancer. It accounts for 80% of all types of breast cancer. On a mammogram, it is usually visualized as a mass with fine spikes radiating from the edges. On physical examination, this lump usually feels much harder or firmer than benign breast lesions. On microscopic examination, the cancerous cells invade and replace the surrounding normal tissues. IDC is divided in several histological subtypes.