[Pathology of the nipple-areola complex : I. Paget's disease of the nipple, variants, and differential diagnoses].

The classical Paget's disease of the nipple is histologically characterized by tumor cell infiltration originating in intraductal or invasive breast carcinoma, immunohistologically by a frequent overexpression of HER2 and clinically by eczema-like changes of the nipple and areola. Variants with different histological, immunohistological, and clinical features are observed in nonclassical forms of Paget's disease, such as isolated Paget's disease of the nipple, anaplastic Paget's disease, Paget's disease with invasion, and pigmented Paget's disease of the nipple. In the differential diagnosis of Paget's disease, benign changes have to be considered, including Toker cell hyperplasia, nipple eczema, and rare dermatoses.