Paget disease (breast)

Paget disease of the breast, which is also known as Paget disease of the nipple, has traditionally been described as a form of breast malignancy characterized by infiltration of the nipple epidermis by malignant cells. Although most cases have underlying focus or foci of in situ or invasive carcinomas, some cases of Paget disease are confined to the skin of the nipple-areola without underlying neoplastic foci.

Epidemiology

The condition can represent 1-5% of breast malignancies. The average age at diagnosis is around the 6^th decade (53-59 years).

Clinical presentation

Eczematous appearing changes of the nipple include reddening, scaling, hyperkeratosis, and crusting of the nipple surface.

Clinical staging

Mammary Paget disease can be classified into four clinical stages:

• stage 0: lesion is confined to the epidermis, without underlying ductal carcinoma in situ (DCIS) of the breast
• stage 1: associated with DCIS just beneath the nipple
• stage 2: associated with extensive DCIS
• stage 3: associated with invasive ductal carcinoma

Pathology

In most cases of Paget of the breast, there are malignant ductal cells that extend to the nipple surface through the terminal lactiferous ducts.

Malignant epithelial (Paget) cells infiltrate and proliferate in the epidermis, causing an eczema-like rash of the nipple and the areolar skin. There are several histologic variants of Paget disease including:

• adenocarcinoma-like cell type
• spindle cell type
• anaplastic cell type
• acantholytic cell type
• pigmented cell type

Radiographic features

Mammography

Mammary Paget disease can be undetectable on mammography in ~50% of cases ². Features that may be evident on mammography include skin thickening, nipple retraction, subareolar or more diffuse malignant microcalcifications, and discrete subareolar mass(es).

Breast MRI

MR imaging may play an important role in the selection of patients with Paget disease for breast-conserving therapy if there is no clinical or mammographic evidence of breast carcinoma. Abnormal nipple enhancement and linear clumped enhancement indicative of DCIS in association with Paget disease.

Treatment and prognosis

Traditionally, treatment has been a mastectomy with nodal dissection. However, with MRI, breast-conserving therapy is more frequently being used.

History and etymology

Paget disease of the breast is named after Sir James Paget (1814-1899), the British surgeon and pathologist, who first described it in 1874 ⁶.