How is paget disease of the nipple?

➢ caused by the extension of DCIS up the lactiferous ducts and into the contiguous skin of the nipple, producing a unilateral crusting exudate over the nipple and areolar skin. ➢ Unlike Paget disease of the vulva, Paget disease of the nipple stems from in situ extension of an underlying carcinoma. ➢ The prognosis of the carcinoma of origin is affected by the presence of Paget disease and is determined by other factors.