[3] However, unlike MPD, which occurs in large milk-carrying ducts in the breast and then extends into the epidermis,[3] EMPD begins in glandular regions rich in apocrine secretions outside the mammary glands.

Patients with EMPD present with typical symptoms, similar to MPD,[3] such as severe itchiness (also called pruritus), rash, plaque formation, burning sensation, pain and tenderness.

[10] The lesion is clearly separated from normal skin in most cases, and sometimes scattered areas of white scale can be present, giving a "strawberries and cream" appearance.

[8] Patients are often misdiagnosed with eczema or dermatitis[8] and a delay of 2 years is expected from the onset of symptoms before a definitive diagnosis has been reached.

[15] Lack of positivity for hormone receptors and HER2 protein is overexpressed meaning that the cells are dividing rapidly and can be indicate an aggressive and more recurrent disease.

[citation needed] Primary EMPD is of cutaneous origins and is found within the epidermis or the underlying apocrine glands.

[1] Although it is limited to the epithelium, it has potential to spread and progress into an invasive tumour, metastasising to the local lymph nodes and distant organs.

[16] adenocarcinoma of skin appendage Many chemotherapy treatments have been used, however the results are not desirable as prognosis remains to be poor.

[16] In lieu of surgery, radiotherapy is also an option and is especially preferred for elderly patients or for inoperable cases where the tumour size is too large.

[6] This form of treatment is also considered as possible adjuvant therapy following excision to combat the high recurrence rate.

[2] However, there are side effects of radiotherapy, including but not limited to: vulvitis, post-radiation atrophy of mucous membranes, vaginal stenosis and sexual dysfunction.

[16] In primary EMPD, if invasion of the underlying tissue is non-existent or even minimal, treatment options are more likely to be effective, however, if there are signs that the disease has metastasised, the prognosis is usually poor.

[16] Other areas where EMPD can be found, although very rarely, include: the axillae, eyelids, external auditory canal, umbilical region, trunk and extremities.

[3] Radcliffe Crocker, in 1889, then described EMPD following an observation of a patient with urinary carcinoma affecting the penis and scrotum,[18] showing symptoms that were almost identical to MPD as described by Paget.