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.