Medical & Surgical Dermatology
The Mohs Surgical Procedure
Mohs micrographic surgery is a specialized, highly effective technique for the removal of skin cancer. The procedure was developed in the 1930s by Dr. Frederic Mohs at the University of Wisconsin and is now practiced throughout the world. Mohs surgery differs from other skin cancer treatments in that it permits the immediate and complete microscopic examination of the removed cancerous tissue, so that all “roots” and extensions of the cancer can be eliminated. Due to the methodical manner in which tissue is removed and examined, Mohs surgery has been recognized as the skin cancer treatment with the highest reported cure rate.
Mohs Surgical Overview
In Mohs surgery, the dermatologist performs the dual role of skin cancer surgeon and pathologist. The Mohs procedure involves the surgical removal of the visible portion of the skin cancer, along with a layer of the surrounding skin. This tissue is then divided into sections and color-coded by the Mohs surgeon, while corresponding reference marks are made on the patient to indicate the source from which each section was taken. The surgeon then draws a map of the surgical site, and the tissue is processed to create microscope slides for examination and analysis by the physician. He or she then examines the undersides and edges of each section microscopically for evidence of remaining cancer cells. If cancer is still present, the involved areas are carefully marked on the map and the patient is prepared to undergo removal of another layer of tissue. It is important to note that any additional tissue is removed only from the area(s) in which cancer cells are still evident on microscopic examination. This process is repeated until no further evidence of cancer remains at the surgical site.
Indications for Using Mohs Surgery
Mohs surgery is indicated for skin cancers in anatomic areas in which preservation of the maximum amount of surrounding healthy tissue is critical for functional and/or cosmetic purposes, such as the eyelids, nose, ears, fingers, toes, and genitalia. It is also used to excise previously-treated skin cancers which have recurred over time, skin cancer containing scar tissue, large skin cancers, skin cancers with borders that are not clearly defined, and skin cancers that demonstrate certain unusual growth patterns. Skin cancers with aggressive subtypes, such as sclerosing or infiltrating basal cell carcinomas, also may require the use of Mohs surgery. The dermatologist will consider a number of factors in determining whether Mohs surgery is indicated for a particular skin cancer.
Clinical studies have demonstrated that Mohs surgery provides five-year cure rates approaching 99% for new cancers and 95% for recurrent cancers. Important advantages of the Mohs procedure are that it allows the greatest amount of surrounding healthy tissue to remain intact, potentially reducing the size of the final surgical defect and resulting scar; and that the methodical manner in which all lateral and deep tissue margins are examined enables the surgeon to detect and remove any “roots” of the skin cancer that may be present, which greatly reduces the likelihood of recurrence.
Mohs Training and Experience
Residency training in dermatology provides the basic skill set from which the Mohs technique is derived: skin cancer pathology, cutaneous histopathology, dermatologic surgery, and the repair of complex surgical defects. The Mohs surgeon continues to enhance these skills in Residency and once in practice through repeated observation and performance of the Mohs tecnique. Challenging medical education courses with an emphasis on Mohs surgery, observational preceptorship training with other highly-experienced Mohs surgeons, and formal Mohs fellowships all are available options for post-Residency Mohs training. Each experience encourages further advancement and refinement of the dermatologist's surgical skills and enables him or her to treat progressively more complex Mohs cases.
Team Approach to Skin Cancer Treatment
In an effort to provide the best possible medical care, Mohs surgeons sometimes treat patients in partnership with other specialists such as oculoplastic surgeons, ENT (ear, nose and throat) specialists, oral surgeons, plastic surgeons, and radiation oncologists. If indicated for your condition, your Mohs surgeon will discuss these options in detail with you.
Special Qualifications of the Mohs Surgeon
Water’s Edge Dermatology physicians performing Mohs
surgery have specialized skills in dermatology, dermatologic
surgery, dermatopathology and Mohs surgery. Basic and
advanced training in Mohs surgery is available through
selected Residency programs, specialized fellowships,
observational preceptorships and intensive training
courses. In addition, your Water’s Edge Dermatology Mohs
surgeon has the required surgical and laboratory facilities
and is supported by a well-trained Mohs nursing and
histotechnological staff. Your Water’s Edge Dermatology
Mohs surgeon can provide you with detailed information
regarding his or her training in the above disciplines, as well
as all applicable professional affiliations.
Advantages of the Mohs Surgical Procedure
Some skin cancers can be deceptively large - far more
extensive under the skin than they appear to be from the
surface. These cancers may have “roots” in the skin, or
along blood vessels, nerves, or cartilage. Skin cancers that
have recurred following previous treatment may send out
extensions deep under the scar tissue that has formed at the
site. Mohs surgery is specifically designed to remove these
cancers by tracking and removing these cancerous “roots”.
For this reason, prior to Mohs surgery it is impossible to
predict precisely how much skin will have to be removed.
The final surgical defect could be only slightly larger than
the initial skin cancer, but occasionally the removal of the
deep “roots” of a skin cancer results in a sizeable defect.
The patient should bear in mind, however, that Mohs surgery
removes only the cancerous tissue, while the normal tissue is
The Mohs Surgical Procedure
Typically, Mohs surgery is performed in your Water’s Edge
Dermatology office. Although the patient is awake during
the entire procedure, discomfort is usually minimal and
no greater than it would be for more routine skin cancer
surgeries. The Mohs surgical procedure is illustrated in the
Insurance Coverage for Mohs Surgery
Most insurance policies cover the costs of Mohs surgery and
the reconstruction of the resultant surgical area.
Patient Preparation for Surgery
If you are taking prescription medications, continue to take
these unless otherwise directed by a physician. However,
you should inform your Mohs surgeon if you are taking
blood-thinning medications such as coumadin, Plavix, aspirin,
aspirin substitutes (such as Advil, Motrin, Nafton, Naprosyn,
etc.), vitamin E, gingko, garlic, ginseng, ginger, ephedra
or other nutritional supplements. These medications and
supplements can sometimes cause an increased chance of
bleeding after surgery.
It is important that you obtain a good night’s rest and eat
normally on the day of your surgery. For your comfort, it is
recommended that you wear casual, layered clothing. You
may also wish to bring a light snack and a book or magazine
to help occupy your waiting time. Also, it may be advisable
to arrange for someone to drive you home following
surgery, if needed.
Minor Post-Surgical Discomfort Expected
Most patients do not complain of significant pain. If there is
some discomfort, normally only Tylenol is required for relief.
However, stronger pain medications are available and will
be prescribed when needed. You may experience some
bruising and swelling around the wound, especially if surgery
is performed near the eye area.
Options for Post-Surgical Reconstruction
After the skin cancer has been removed, your Water’s Edge
Dermatology surgeon will discuss the following options with you:
1) Allowing the wound to heal naturally, without
the necessity of additional surgery (which may
produce the best cosmetic result).
2) Simple or complex wound repair performed by the
3) Referral to the original referring physician for
4) Referral to another surgeon for wound repair.
Wound Healing, Scarring, and Scar Revision
As with all forms of surgery, a scar will remain after the skin
cancer is removed and the surgical area has completely
healed. Mohs micrographic surgery, however, will leave
one of the smallest possible surgical defects and resultant
scars. Often, wounds allowed to heal on their own result in
scars that are barely noticeable. Even following extensive
surgery, results are frequently quite acceptable. In addition,
scars do have the ability, through the body’s own natural
healing properties, to remodel and improve in appearance
for a six to twelve month period. There are also many other
techniques available to the patient for enhancement of
the surgical area following skin cancer surgery. Depressed
or indented scars may be elevated, using a filler such as
Radiesse® or Sculptra®. Likewise, a raised or roughened
scar may be smoothed, using laser resurfacing or chemical
peeling techniques. Skin flaps and grafts also may require
a subsequent “touch up” procedure, to further improve their
Questions Frequently Asked by Patients
Is Mohs surgery the best treatment option for all skin cancers?
If you have any type of suspicious skin lesion you should seek evaluation by a dermatologist. If skin cancer is suspected, he or she may recommend and perform a biopsy. Mohs surgery may be recommended based on the type and location of the skin cancer, as well as other factors. If your dermatologist does not perform this technique, he or she will be able to refer you to a Mohs surgeon in your area.
Patients attempting to locate a Mohs surgeon on their own may elect to use the Surgeon Locator under Patient Information. Some members may have their own patient information pamphlets that summarize their Mohs training, experience, and practice information.
Is Mohs surgery more expensive than other types of skin cancer treatment?
Because it involves a special multi-step process, Mohs surgery is typically slightly more expensive than other skin cancer treatments. It is important, however, to consider the advantages of the Mohs technique (healthy tissue sparing capabilities, lower recurrence rate, etc.) in examining the total cost. Your physician's billing specialists will be able to provide you with estimated insurance reimbursement rates and/or possible payment plan information.
Will Mohs surgery be covered by my insurance plan?
Mohs surgery is covered by most insurance plans, including Medicare. Please enlist the aid of your employee benefits administrator and/or physician’s billing specialist to determine estimated out-of-pocket expenses. The ASMS does not maintain specific insurance plan information for our members, so you will need to inquire directly.
Will Mohs surgery leave a scar?
All surgical procedures have the potential for some degree of visible scarring. The appearance of a post-Mohs surgical scar will depend on several factors, including size and location of the final defect, individual skin characteristics, and the reconstruction options available. You should keep in mind, however, that the tissue-sparing nature of the Mohs technique may result in a smaller, less noticeable scar than other skin cancer removal methods. The Mohs surgeon also may be able incorporate suture lines into the patient's natural skin lines and folds. Most scars improve in appearance naturally over time, and future scar revision techniques may employed if necessary.
My skin cancer is in a very noticeable facial area and I am concerned about my appearance following Mohs surgery. Should I have the skin cancer removal performed by a plastic surgeon?
We would recommend removal of the skin cancer by a dermatologist with specialized training in Mohs surgery, due to the histopathology component of the procedure. You may wish to discuss with the Mohs surgeon the option of having a plastic surgeon perform the closure following Mohs surgery, if this is your preference. Your Mohs surgeon's office would be able to help coordinate this type of shared treatment approach.
How can I locate a board certified Mohs surgeon?
It is important to note that there is no formal board certification process specific to Mohs surgery, as the procedure represents just one technique utilized by dermatologists in the treatment of skin cancer. ASMS Fellow and Affiliate members must be Board certified in dermatology by the American Board of Dermatology or the American Osteopathic Board of Dermatology. The surgical, histopathologic interpretation and reconstruction components of Mohs surgery are routinely taught to dermatologists in their Residency training. In addition, dermatologists are examined in these areas by their respective Boards.