Hudson Dermatology offers a specialized technique called Mohs micrographic surgery, which we provide in our Fishkill, Kingston, Somers and Tarrytown offices. It is usually used to treat cancers in cosmetically sensitive areas like the face, cancers that are unusually aggressive, or those that have recurred after more conventional treatments.

Our Mohs surgeon is Dr. Ross Zeltser, who heads our offices in Tarrytown and Somers and is a partner in the practice. Dr. Zeltser has been performing Mohs procedures for Hudson Dermatology since 2008, and joined the practice fulltime in 2017. Since 2013, he has been rated by his peers as one of Westchester’s top doctors by Castle Connolly, whose selections are published by Westchester magazine.

What Is Mohs Surgery?

Mohs surgery is a specialized technique used to treat certain skin cancers. It is typically used to treat cancers in cosmetically or anatomically sensitive areas, cancers that are unusually aggressive, or those that have recurred after more conventional treatments. You can read more about Mohs surgery, and you can read more about skin cancer.

The Mohs Procedure

The Mohs procedure involves surgically removing skin cancer layer by layer and examining the tissue under a microscope until healthy, cancer-free tissue around the tumor is reached. The wound will then be sutured closed. This will usually be done in our office on the same day, but occasionally, for certain large or cosmetically sensitive wounds, the wound will need to be repaired by another specialist in a different location on the next day. This will be arranged in advance.

This video will introduce you to the Mohs procedure.

What Should I Expect?

Initial removal of your skin cancer will be performed using local anesthesia. You will then be asked to wait while the tissue is processed and examined under a microscope. This first stage can take from one to two hours. If more tissue needs to be removed, this process will need to be repeated, until all the cancer is eliminated.

This procedure is usually completed in one or two stages, but can sometimes take several more. Therefore we ask that you arrange to be here all day, even though most patients are finished within two to four hours.

Once all the skin cancer is cleared, you will be ready for closure of the wound. In the majority of cases, the closure will be done here on the same day. If not, you will leave the office with a dressing on the wound, and with an appointment for closure elsewhere the next day. This will be arranged in advance by our office.

This can be a long day, and we want to make it as easy as possible for you. There is a television in an area of the waiting room. Feel free to bring a companion, an extra pillow, reading material, knitting, snacks or whatever you need to be comfortable. It is fine to leave the office to do a brief errand or visit a restaurant nearby.

Frequently Asked Questions

Why is it called Mohs surgery? What does Mohs stand for? The term “Mohs” refers to Dr. Frederic Mohs, Professor of Surgery at the University of Wisconsin, who developed this surgical technique in the 1930s. The technique has undergone many refinements and has come to be known as Mohs micrographic surgery or simply Mohs surgery in honor of Dr. Mohs.

I don’t see anything after my biopsy. Do I really need to be treated? Yes. Following a biopsy, your skin cancer may no longer be visible. However, the surface lesion that was removed can represent the “tip of the iceberg.” More tumor cells may remain in the skin. These can continue to grow downward and outward, like roots of a tree. These “roots” are not visible with the naked eye. If they are not removed, the tumor will likely reappear and require more extensive surgery. The seminal study on this subject was done by Dr. Gary Rogers, who was Dr. Zeltser’s fellowship director. See reference below.*

Tumors that are neglected can spread deeply into the skin and invade nearby structures. On rare occasions, these cancerous cells can metastasize to lymph nodes and other organs in the body.

Why does my skin cancer need to have Mohs surgery? Mohs surgery has the highest cure rate. It is appropriate for most skin cancers and especially suitable for skin cancer that:

  • Is in an area where it is important to preserve healthy tissue for maximum functional and cosmetic result
  • Was treated previously and has come back
  • Is located near scar tissue
  • Is large
  • Does not have clearly defined edges
  • Is growing rapidly or uncontrollably
  • Is of an aggressive subtype (i.e., sclerosing or infiltrating basal cell carcinoma)
  • Develops in organ transplant or lymphoma patients
Please note: This is not an exhaustive list of the instances where Mohs surgery is the most appropriate option for your skin cancer.

How long will I be there? Most Mohs surgery is completed within two to four hours, but we ask that you make no other plans and be available to stay the entire day in case more time is needed. Our waiting room and treatment rooms are equipped with HEPA air filters, or if you prefer you can wait in your car. For security reasons, we do not provide public WiFi, but our offices have good cell reception.

What should I wear? We suggest that you wear casual, loose, comfortable clothing and avoid clothing that must be pulled over your head. Also, please do not wear make-up if the surgery is on your face.

Can I eat or drink? All procedures are done under local anesthesia, and therefore you can eat and drink unless your reconstruction is scheduled at an outside surgical facility under sedation the same day. We suggest that you eat a filling breakfast, since you may have to spend considerable time with us. There will be opportunities to eat while in the office. Feel free to bring a snack and drinks. (For patient safety, there are currently no shared snacks available in the office.)

Do I need to have someone drive me home? All procedures are done under local anesthesia, and therefore you will not be drowsy. A driver will not be necessary unless instructed otherwise (because of surgery on eyelids or sedating medications, for example). You are welcome to bring a companion.

Do I need to stop my blood thinning medication or aspirin? We are able to perform your surgery safely while on these medications. Unless instructed otherwise by another physician, there is no need to discontinue these medications.

What about other medications? Please try to stop ibuprofen (Advil, Motrin) or naproxen (Aleve, Naprosyn) about two days prior to surgery if you are just taking these for minor aches and pains. Acetaminophen (Tylenol) is a good substitute that does not increase bleeding. You may, however, safely stay on your pain medication if you need it to control your arthritis, back or other pain and Tylenol does not work for you. Also, please stop taking Vitamin E.

What can I expect after the surgery? You will have a dressing on the wound and will be given specific instructions regarding wound care. There should be minimal pain, for which you can take Tylenol. If the doctor anticipates additional pain, you might receive a prescription pain medication. If the procedure is on the face or scalp, you might have facial swelling and/or bruising for several days afterwards. Ice packs should help for this. You should be able to return to work within one to days in most cases. Suture removal will be scheduled for about one to two weeks after surgery. It is normal to experience numbness in the area and/or occasional tingling or “pin-and-needle” sensations within a healing scar for several months.

Will Mohs surgery leave a scar? Yes. Like any treatment for skin cancer, Mohs surgery will leave a scar.

Mohs surgery preserves as much healthy skin as possible and maximizes options for repairing the surgical defect, once the tumor is completely removed. Once the Mohs surgeon has completely removed your skin cancer through Mohs surgery, reconstruction for optimizing the final functional and cosmetic result becomes the highest priority.

Generally, a post-surgical scar improves with time and can take a year or more to fully mature. As your surgical site heals, new blood vessels can appear and support the healing changes occurring underneath the skin. This can result in the reddish appearance of the scar. This change is temporary and will improve with time.

In addition, the normal healing process involves a period of skin contraction, which often peaks 4 to 6 weeks after the surgery. This may appear as a bumpiness or hardening of the scar. On the face, this change is nearly always temporary and the scar will soften and improve with time. If you have a history of abnormal scarring, such as hypertrophic scars or keloids, or if there are problems with the healing of your scar, injections or other treatments may be used to optimize the cosmetic result. We are available for you throughout the healing process to discuss any concerns that may arise.

Is Mohs surgery the most cost-effective treatment option? Because of Mohs surgery’s high success rate, most patients require only a single surgery. This surgery usually includes the repair of the wound as well. Other methods might require additional surgeries and pathology readings in order to repair the wound and to treat the cancer if it is not completely removed. Each of these additional surgeries and pathology readings require separate fees, while a single Mohs surgery procedure includes all of these into one fee.

How can I find out more? Visit the American College of Mohs Surgery website. And please feel free to contact our Mohs coordinator, Zina, at (845) 896-7730 if you have any other questions.

*Holmkvist, Kristina A., MD, Rogers, Gary S., MD and Dahl, Patrick R., MD, “Incidence of residual basal cell carcinoma in patients who appear tumor free after biopsy,” Journal of the American Academy of Dermatology, 1999 October, Volume 41, Issue 4, pages 600-605.


Find more information about Mohs surgery at the American College of Mohs Surgery web site.