Paget's disease of the breast

Paget's disease of the breast is a rare malignancy of the nipple-areola complex, comprising 0.5-4% of all breast cancers which is often associated with an underlying in-situ or invasive carcinoma in the breast parenchyma. It is manifested by progressive eczematoid changes of the areola with persistent soreness or itching. Due to the seemingly benign appearance, diagnosis is often delayed by more than six months. There are two main theories regarding the histogenesis of the disease: the epidermotropic and the in-situ transformation. The first suggests that Paget cells are ductal cells that have migrated from an underlying carcinoma of the breast parenchyma to the epidermis of the nipple. The second postulates that nipple keratinocytes undergo transformation into malignant cells independent from any pathology within the breast parenchyma. Prognosis is determined by the nature of the concurrent tumor in the breast. In 50% of cases a palpable mass is evident and it usually represents an infiltrating carcinoma with involved axillary lymph nodes. In the absence of a mass the prognosis is invariably better as it usually reflects a noninvasive tumor (DCIS). The standard treatment has been mastectomy. However in an era when breast conserving surgery is implemented even for advanced infiltrating breast tumors, there might be a role for such a treatment for selected patients with Paget's disease.