Intraepidermal malignancy in breast skin: A tale of two tumours

Mammary Paget's disease most commonly affects the nipple areolar complex and is frequently associated with an underlying in-situ or invasive breast carcinoma. Pagetoid Bowen's disease of the breast is extremely rare and contains cells which morphologically resemble those of Paget's disease and may also express CK7 on immunohistochemistry. Here, we report two unusual cases of a 42-year-old Chinese woman with a recurrence of high grade ductal carcinoma in-situ presenting as mammary Paget's disease away from the nipple areolar complex, and a 65-year-old Chinese woman with pagetoid Bowen's disease of the breast skin. To our knowledge, there are only two case reports that are similar to the former and one to the latter.