Broadening the Understanding of Mucinous Carcinoma of the Breast

Mucinous carcinoma (MC) is a rare invasive neoplasm comprising only 2% to 4% of all breast cancers,1 commonly affecting women under the sixth through eighth decades of life. Also referred to as colloid carcinoma, MC has been historically described as a circumscribed, round mass with indolent behavior occurring in older women. This is an oversimplification. The imaging appearance, biological behavior, and demographic profile of MC are variable, often correlating with histologic subtype and nuclear differentiation and in some instances mimicking benign pathologies. Broadening the understanding of MC will help radiologists establish concordance, guide clinical management, and accurately surveille cases in multidisciplinary tumor boards.