Extramammary Paget's disease of the breast: an unusual location with prognostic implications

[Pathology of the nipple-areola complex : I. Paget's disease of the nipple, variants, and differential diagnoses]

The classical Paget's disease of the nipple is histologically characterized by tumor cell infiltration originating in intraductal or invasive breast carcinoma, immunohistologically by a frequent overexpression of HER2 and clinically by eczema-like changes of the nipple and areola. Variants with different histological, immunohistological, and clinical features are observed in nonclassical forms of Paget's disease, such as isolated Paget's disease of the nipple, anaplastic Paget's disease, Paget's disease with invasion, and pigmented Paget's disease of the nipple. In the differential diagnosis of Paget's disease, benign changes have to be considered, including Toker cell hyperplasia, nipple eczema, and rare dermatoses.

Acinar Pattern of Mammary Paget?s Disease: A Case Report

Mammary Paget's disease (MPD) is an uncommon in situ neoplasm of the nipple-areolar complex and surrounding skin. It is almost always associated with mammary ductal carcinoma in situ (DCIS), high-grade or invasive carcinoma, usually of ductal origin. MPD has only rarely been described in association with specialized forms of breast carcinoma. We report an unusual case of an acinar pattern of MPD with low-grade cytological atypia, associated with invasive papillary carcinoma and micropapillary DCIS of the lactiferous ducts, in an 83-year-old woman. Most cases of MPD are characterized by intraepidermal spread of discohesive glandular epithelial cells with high-grade nuclear atypia. A predominant acinar pattern of MPD is extremely uncommon and, to our knowledge, has not been formally reported. The histological features and differential diagnosis are discussed.

Mammary and extramammary Paget's disease

Paget's disease is an intra-epidermal adenocarcinoma seen over the nipple/areola (mammary Paget's disease) or in extramammary body zones, such as the anogenital and perineal skin and the axilla. Mammary and extramammary Paget's disease share many common clinicopathological features but also show several differences, namely, with regard to pathogenesis and association with underlying malignancies. Indeed, mammary Paget's disease is as a rule associated with an underlying breast carcinoma whereas association of extramammary Paget's disease with underlying (skin or visceral) malignancies occurs much less frequently. We review here the main clinicopathological and therapeutic features of mammary and extramammary Paget's disease.