Andrew M. Herbst MD
Fellow American Academy of Dermatology
Fellow American College of Mohs Surgery
(203) 957-3535
148 East Ave., Suite 3B
Norwalk, Connecticut 06851


What is Mohs surgery?

Mohs Micrographic surgery is a safe and highly effective technique whereby skin cancers are removed under complete microscopic control. Dr. Fredric Mohs developed the specialized technique in the 1930’s. In Mohs surgery, a thin margin of normal skin is removed around the visible cancer. Detailed maps are then drawn of the area, and the tissue is completely examined under the microscope to be sure all the cancer and its roots are gone. If any cancer remains, additional tissue is removed from those areas and analyzed. This process is repeated until the cancer has been completely removed.
What is the advantage of Mohs surgery?

By using the mapping technique and complete microscopic control, the Mohs surgeon can pinpoint areas involved with cancer that are otherwise invisible to the naked eye and can sometimes be missed by a traditional excision. Therefore, even the smallest microscopic roots of cancer can be removed. Benefits of this meticulous technique include its ability to preserve as much normal skin as possible and offer the highest possibility for cure.
What should I expect on the day of my surgery?

Surgery begins in the morning and is performed in the office as an outpatient. A local anesthetic is injected into the skin to numb the area to be treated. Once the area is numb, the visible cancer is removed as well as a thin layer of tissue around the cancer. A temporary dressing is applied. The tissue is then mapped by the surgeon and taken to our on-site laboratory where it is color coded, processed, and examined under the microscope. This part of the procedure takes about one hour. If additional tumor is identified, the process is repeated until all of the cancer is removed. The number of stages or layers required varies for each patient and depends upon the size and depth of the tumor. On average, most patients have one or two layers of tissue removed. Since we cannot predict in advance the number of stages necessary to fully remove the tumor, you should plan on spending at least 4 hours with us. (Most patients are not in the office that long). Once the area is cancer free, the surgeon will discuss the options of wound healing and surgical repair. This may include suturing the area, performing reconstructive surgery using a skin graft of flap, or allowing the area to heal on its own. If surgical repair is required, it is done in our office usually on the same day as the Mohs surgery. Following the repair, a dressing is applied and you will be given instructions on wound care and dressing changes. There are times when patients will require the repair to be performed by an outside plastic surgeon. This is more likely on skin cancers on the eyelid or very large skin cancers located on other parts of the face or body
What do I need to do to prepare for my surgery?

Know the exact location of your surgical site. It seems strange but very often biopsy wounds heal so well it is hard to find the site. This does not mean that the roots of the skin cancer are gone. If you are unsure of the biopsy site, there are some useful practices to help us find it. Your dermatologist may have taken photo of the site or made a diagram; please make sure they forward it to us or bring it with you to your appointment. While the biopsy wound is still fresh you can take a photo of the site for us to examine or come to us and we can photograph it. If you have any doubt you can return to your dermatologist and they may photo the location or circle it with a surgical marker. There are rare instances, depending on type and size of your skin cancer that the biopsy will have removed the entire growth and the area can be followed closely or treated with a topical cream.

Breakfast: Because the procedure is performed under local anesthesia, you may eat breakfast in the morning.

Medications: Please take your all your daily prescription medications prior to surgery, including blood thinners and especially, blood pressure medications. Also bring a list of your medications with you, including non-prescriptions drugs.

If you have been prescribed the blood thinner Coumadin please make sure our office has a copy of your INR blood test from the office of the physician who prescribes your Coumadin. This must have been taken within one week of your surgery appointment. If you are on other blood thinning medications under the care of a physician such as Asprin, Plavix or Pradoxa you should continue them.

If you are taking Aspirin not prescribed by a physician please stop one week prior to surgery.

If you take Alleve, Naprosyn, Advil, Motrin or Ibuprofen please do not take 2 days prior to surgery.

Please discontinue all vitamins and supplements one week prior to surgery.

Alcohol: Alcohol promotes bleeding. We ask that you avoid alcoholic beverages 24 hours before and after surgery.

Smoking: Smoking affects wound healing by diminishing blood supply at your surgery site and can lead to excess scarring. We ask that you discontinue smoking as soon as is possible prior to surgery. If you cannot stop completely, decreasing the amount you smoke will still be of benefit.

Transportation: You may want to make arrangements for someone to drive you to and from our office the day of surgery. This person may stay with you during the waiting period to keep you company between layers. Although you may be finished earlier, please plan on spending at least 4 hours with us. If the area being treated is near your eye, (upper nose, forehead, upper cheeks) the bandage that we apply may interfere with the positioning of your glasses or obstruct your vision. In these instances it will be necessary that you arrange transportation.

Passing Time: We would like to make the time you spend with us as pleasant and comfortable as possible. You may want to bring reading material to occupy your time while waiting for the microscope slides to be processed and examined. We have a television and wireless internet access.

Lunch: We will have drinks and snacks available for you while you wait. You may also bring a sandwich or other snacks if you like.

Attire: Please dress comfortably the day of surgery.

What should I expect after surgery?

If you have any problems at home after surgery, please do not hesitate to call our office. We will be glad to answer any questions. Instructions for wound care will be discussed at the completion of surgery and you will receive written instructions as well.

Will I have pain after surgery?

The surgical site may be sore for several days after surgery. If there is any discomfort, Tylenol is usually adequate for relief. We may prescribe stronger pain medications depending on the extent of the procedure. Avoid taking aspirin or ibuprofen-containing medications as they may cause bleeding.

Will I have bruising after surgery?

Bruising and swelling are common after surgery. This may not peak until 48 hours following the surgery. We do not recommend planning your surgery date around an engagement where physical appearance is important.

Can I exercise after surgery?

Activities, including exercise or heavy lifting, may be restricted until stitches are removed. It depends on the location and extent of surgery. To be safe it is advised that you do not schedule surgery at a time when you will need to be physically active in the week after the procedure.

Will the surgery leave a scar?

A scar is formed after any form of surgery. Every effort will be made to decrease the appearance of this scar. Using the Mohs technique allows us to spare healthy tissue and this will help to minimize scarring. Furthermore Dr. Herbst will make every effort to provide you with the best repair option and meticulously perform it.

Will I need to come back?

Suture removal and wound evaluation is usually performed one week after surgery. Periodic visits at least once or twice a year to your referring dermatologist are advisable to monitor for new skin cancers or signs of recurrence from previous procedures. Since statistics show that a patient with skin cancer has a higher chance of developing another one, follow-up is very important.

How can I protect myself from developing more skin cancers?

Here are some helpful hints to avoid the damaging effects of the sun and protect your skin from more injury:

1. Cover up with protective clothing, hats, beach umbrellas, etc. even on cloudy days, to minimize unnecessary exposure.
2. Avoid the sun at its most intense hours form 10:00 am to 4:00 pm if possible.
3. Regularly and liberally apply a board spectrum sunscreen (SPF 30 or greater with UVA and UVB coverage) on a daily basis. Re-apply every 2-3 hours during prolonged sun exposure.


Patients diagnosed with skin cancer are at a higher risk of developing additional skin cancers. Sun protection is very important so that you can continue to enjoy spending time outdoors.

When possible try to avoid peak hours of sun exposure, 10 am to 3pm. In addition, the following tactics are useful in limiting exposure to ultra violet radiation. Always wear a wide brimmed hat and try to use clothing with ultraviolet protection.

Sunscreen use is important in the prevention of future skin cancers and premature aging of the skin. Besides visible light, sun light contains ultra violet B and ultraviolet A radiation. The SPF number refers to protection against UVB and it is recommended that you use a sunscreen with at least SPF of 30. Although ultraviolet A radiation does not burn skin, it contributes to premature aging of the skin and the development of skin cancers. Protection against UVA is NOT indicated by the SPF rating. We recommend choosing a sunscreen with one or more of the following ingredients that provides protection against UVA: parsol (avobenzone), zinc oxide, titanium dioxide or mexaril. In the future those sunscreens labeled Broad Spectrum SPF will be those with adequate UVA protection.

In order to be effective, sunscreen must be applied generously (just enough so that application of any more would be visible!) and reapplied every 2- 3 hours regardless of what you are doing and immediately after swimming. Although some sunscreens are more water resistant than others, there is no such thing as a waterproof sunscreen!

To download these documents to your computer, right-click the link and choose "Save Target As".

PDF Wound Care Instructions (No Sutures) (PDF File)
PDF Wound Care Instructions For Patients With Sutures (PDF File)
PDF Wound Care Instructions For Steri Strips and Absorbable Sutures (PDF File)