Paget disease of the nipple
• It is a rare presentation of breast cancers (1 to 4%).
• Presents as a unilateral erythematous eruption with a scaly crust.
• Pruritus is common presentation and often mistaken for eczema. Malignant cells extend from ductal DCIS into nipple skin without crossing the basement membrane.
• Commonly associated with underlying invasive carcinomas or in situ ductal carcinoma.
• These carcinomas are poorly differentiated, ER-negative and overexpress HER2/Neu.
• The epidermis contains clusters of ductal-type carcinoma cells that are larger and have more abundant pale cytoplasm than surrounding keratinocytes.
