ABSTRACT
The primary cause of EMPD is unknown, and the mechanisms of pathogenesis are highly debated. It is often felt to arise as a primary intraepidermal neoplasm of glandular origin, while others are thought to result from epidermotropic spread of an underlying dermal adnexal neoplasm or direct extension of a regional malignancy with adjoining epithelium.4,5 This viewpoint is supported by studies showing that up to 25% of cases of EMPD have associated underlying adnexal or visceral malignancies with contiguous
spread, although regional variations exist.3,5 When there is extensive dermal invasion of Paget cells, it may be impossible to definitively say whether the malignancy originated in the epidermis or adnexal structures.
