mammary Paget disease (MONDO_0002648, a Monarch Disease Ontology entry) can be described as follows. A malignant neoplasm in which there is infiltration of the skin overlying the breast by neoplastic large cells with abundant pale cytoplasm and large nuclei with prominent nucleoli (Paget cells). It is almost always associated with an intraductal or invasive ductal carcinoma of the breast. The clinical features include focal skin reddening, and eczema. Retraction of the nipple may sometimes occur. Also known as: Paget cell neoplasm, Paget disease of the breast, Paget's disease of breast, Paget's disease of the breast, breast Paget disease, mammary Paget's disease.