What is Mohs Surgery?

Mohs surgery is a precise microscopically-controlled surgical process in which a dermatologist performs the surgery and then examines the margins of the removed tissue immediately under a microscope to determine if any cancer remains. Mohs micrographic surgery was originally developed in the 1930s by Dr. Frederic Mohs at the University of Wisconsin. Traditional Mohs surgery is often used when a defined area of extramammary Paget's disease (EMPD) is located.

For larger areas of EMPD, 'slow Mohs' may be used. Slow Mohs (or staged excision) is a way of removing extramammary Paget's disease skin cancer in a precise way. Often this is done over a number of patient visits. During each procedure the Mohs surgeon removes tissue but instead of immediately examining the tissue in the surgical suite under a microscope, it is sent off to pathology. The Mohs surgeon marks the samples carefully as to be able to determine where the tissue originated on the patient. The patient is often bandaged and sent home until the pathology review is completed.

Slow Mohs surgery requires careful communication between the surgeon and the pathology laboratory to insure that specimens and pathology results are correlated. 

When the results of the pathology are returned, and all the edges are determined to be free of cancer, the Mohs surgeon may close the site or refer the patient to another physician. Slow Mohs can require many visits back to the surgeon, until the edges of the cancer can be found.

In cases where the cancer removal has been excessive, a surgeon specializing in that part of the body may be required. For example, a colorectal surgeon may be required when surgery is necessary around the anus. A reconstructive urologist surgeon is often used on male EMPD cases that involve the scrotum, penis or other areas around the genitals.  

Having a team of physicians such as a Mohs surgeon and a reconstructive urologist, in the cases of men, is a common way to treat EMPD when EMPD is covering a large area.  Women with EMPD may consult with a Mohs surgeon and a gynecologic oncologist.

Extramammary Paget's disease patients often look for physicians who are board-certified in dermatology and routinely perform Mohs surgery. The more experience a doctor has performing Mohs surgery – specifically with EMPD cases – the better prepared they are to anticipate and prevent complications.

Mohs training and certification can vary widely amongst physicians and not all Mohs surgeons undergo the same training. For example, the American College of Mohs Surgery (ACMS) – founded by Dr. Frederic Mohs – has an extensive program that includes a one or two-year fellowship program. After completing a residency in dermatology, a doctor can apply to participate in an ACMS fellowship-training program. During an ACMS fellowship, doctors undergo operative and non-operative education, pathology, tumor reconstruction, as well as exposure to long-term results, recurrences, and complications. Along with other requirements, an ACMS-approved physician must participate in a minimum of 500 Mohs surgeries during their fellowship. Other organizations – such as the American Society for Mohs Surgery (ASMS) – also provide Mohs training. However, their requirements for Mohs certification are generally less rigorous.

While Mohs surgery was first developed in the United States, the procedure can now be found in many countries. In North America, Mohs surgery is most commonly performed in an out-patient manner with the surgery occurring in a physician’s office under local anesthetic. In other geographical regions Mohs may occur as a surgical procedure in a hospital.

Treatments for extramammary Paget’s disease (EMPD) often differ but frequently include one or more of the following: Mohs surgery, wide local excision (WLE) surgery, topical creams, carbon dioxide (CO2) laser, photodynamic therapy (PDT), cavitational ultrasonic surgical aspiration (CUSA), radiation therapy, skin grafts, and chemotherapy.

The content presented on this website, encompassing both textual material and visual media, serves educational and informational purposes aimed at aiding individuals affected by extramammary Paget’s disease (EMPD) and their families in comprehending the complexities associated with EMPD. It is imperative to note that the website is not designed to serve as a replacement for professional medical advice, diagnosis, or treatment. Furthermore, the website does not advocate for or endorse any specific treatments, tests, physicians, procedures, or products. Should you suspect that you are experiencing symptoms of EMPD, we strongly advise you to seek guidance from your healthcare provider.