Invasive cribriform carcinoma of the breast (ICCB), also termed invasive cribriform carcinoma, is a rare type of breast cancer that accounts for 0.3% to 0.6% of all carcinomas (i.e. cancers that develop from epithelial cells) in the breast. It originates in a lactiferous duct as opposed to the lobules that form the alveoli in the breasts' mammary glands (lobules make the milk which the ducts channel to the breast's nipple). ICCB was first described by Dixon and colleagues in 1983 as a tumor that on microscopic histopathological inspection had a cribriform pattern, i.e. a tissue pattern consisting of numerous "Swiss cheese"-like open spaces and/or sieve-like small holes (see adjacent Figure). The latest edition (2019) of the World Health Organization (2019) termed these lesions invasive cribriform carcinomas indicating that by definition they must have a component that invades out of their ducts of origin into adjacent tissues. In situ ductal cancers (i.e. cancers localized entirely within their tissues of origin) that have a cribriform histopathology are regarded as belonging to the group of ductal carcinoma in situ tumors.
