On gross pathology, eczematoid, erythematous, moist or crusted lesion, with or without fine scaling, infiltration of the nipple, and inversion of the nipple are characteristic findings of Paget's disease of the breast. Eczema changes of the nipple-areolar complex are said to occur due to invasion of the overlying epidermis by malignant (Paget) cells. The commonly accepted hypothesis is that most cases of Paget's disease of the breast originate from in situ or invasive ductal carcinoma of the underlying breast tissue. On microscopic histopathological analysis, epidermal Paget cells which are malignant glandular epithelial cells organized in groups with nest-like patterns or gland-like structures and are preferably located in the epidermal basal layer characteristic of Paget's disease of the breast.On gross pathology nipple and areola show eczematoid, erythematous, moist or crusted lesions, with or without fine scaling, infiltration of the nipple, and inversion of the nipple are characteristic findings of Paget's disease of the breast.Immunohistochemistry is very useful in Paget's disease of the breast for differential diagnoses and histogenesis.  The overexpression of the low molecular weight cytokeratins, notably CK7, and lack of expression of high molecular weight cytokeratins, such as CK10, CK14 and CK20 are observed in 98-100% of Paget's disease of the breast.
Paget's disease of the breast pathophysiology
Breast cancer pathophysiology
Paget's disease of the breast other diagnostic studies
Paget's disease of the breast risk factors
Breast cancer legacy
Breast cancer other imaging studies
Extramammary Paget's disease pathophysiology
Paget's disease of the breast differential diagnosis