Extramammary Paget disease
This article was last reviewed and updated on October 31, 2018
by Emily Goebel, MD FRCPC
Extramammary Paget disease is a type of cancer.
It is a rare form of cancer that starts from cells in the skin of the vulva.
The normal vulva
The vulva is the external part of the female genital tract. It forms the opening of the vagina and includes the mons pubis, labia majora, labia minora and clitoris. The vulva is composed of skin. The surface of the skin is called the epidermis and is made up of squamous cells. The tissue beneath the epidermis is called the dermis, it contains blood vessels and connective tissue.
What is extramammary Paget disease?
The cancer cells in extramammary Paget disease usually stay in the epidermis. If cancer cells are also seen in the dermis, this will be described in your report.
The diagnosis of extramammary Paget disease is usually made after a small sample of tissue is removed in a procedure called a biopsy. The entire tumour will usually be removed fully in a larger surgical procedure called an excision or vulvectomy.
A margin is any tissue that has to be cut by the surgeon in order to remove the tumour from your body. A margin is considered positive when the cancer cells are seen at the edge of the cut tissue.
Margins will only be described in your report after the entire tumour has been removed,
Why is this important? Cancer cells at the cut edge of the tissue (a positive margin) increases the risk that the tumour will come back in the same location after surgery.
Your pathologist may perform a test called immunohistochemistry to confirm the diagnosis and to exclude other cancers that may look similar to extramammary Paget disease.
Extramammary Paget disease will be positive or reactive for immunohistochemical markers such as CK7 and GCDFP-15 and negative or non-reactive for p63 and S100, which you may see included in your pathology report.