Ductal carcinoma in situ.

The incidence of ductal carcinoma in situ (DCIS) has increased significantly in the last 2 decades, due to the diagnosis of asymptomatic cancers by screening mammography. These cancers are usually diagnosed by the presence of calcification on mammography. Histologic classification of these tumors is controversial, and established and proposed classification systems are reviewed. The role of breast conservation in the treatment of many of these lesions is generally accepted, although areas of debate regarding its application in these patients persists.