Definition

A condition in which abnormal cells are found in the lobules (milk glands) of the breast. The cells tend to look larger and more abnormal under a microscope than cells from the more common classic lobular carcinoma in situ (LCIS). PLCIS is more likely to become invasive breast cancer and spread to other tissues in the breast than the more common form is. PLCIS usually occurs in postmenopausal women. Also called pleomorphic lobular carcinoma in situ.