Dr. Chapas and Dr. Chwalek are dermatological surgeons and Fellows of the American College of Mohs Surgery and the American Society of Dermatologic Surgery. They each have completed prestigious fellowships in Mohs Surgery, have performed thousands of Mohs micrographic surgery procedures, and are nationally recognized as two of the top Mohs surgeons in the U.S. In addition, Union Square Laser Dermatology has extensive experience in post-operative treatment of any residual scars, to achieve the best possible final result.

Please find below answers to some common questions about Mohs surgery.


Mohs Surgery Process
Mohs Surgery Process


Mohs Micrographic Surgery, named for Dr. Frederic Mohs who developed the technique, is a highly specialized and precise treatment for skin cancer in which the cancer is removed in stages, one tissue layer at a time. It is an outpatient procedure, performed under local anesthesia, and is distinguished by a specific technique of tissue examination that is unique to Mohs surgery.

The Mohs technique involves removing the cancer containing tissue and marking the edges with colored dyes, to create a map of the specimen. The tissue is then processed onto microscope slides by a Mohs histotechnician in our on-site lab. These slides are carefully examined under the microscope by the Mohs surgeon so that any microscopic roots of the cancer can be precisely identified and mapped. If cancer cells are seen, an additional tissue layer is removed only in areas where the cancer is still present, leaving normal skin intact. This saves as much normal, healthy skin as possible.

Once the cancer has been removed, the Mohs surgeon will explain options for repair of the wound, including natural healing (granulation), stitching the wound together using a side-to-side closure, or using a skin flap or graft.



Mohs surgery has the highest cure rate (up to 99%) for nonmelanoma skin cancers, such as basal cell carcinoma and squamous cell carcinoma. 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 best functional and cosmetic results
• Was treated previously and has come back
• Is located near scar tissue
• Is large, greater than 1 cm in diameter
• 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.


To begin, the appointment process, please have your referring physician fax a copy of your biopsy result and contact information to 212-366-5461, or send it via email to records@unionderm.com. Our staff will contact you to schedule a convenient appointment time. Although a consultation is not generally required, many patients like to meet with Dr. Chapas or Dr. Chwalek prior to the procedure to discuss their unique situation. Patients age 75 or older will need to send a letter of medical clearance from their primary care physician prior to their Mohs surgery date and must be accompanied by a friend or family member on the day of the procedure. Once your appointment is booked, you will receive an email with instructions for completing our medical forms online prior to your visit.


On average, the Mohs surgery procedure is completed in 2-4 hours. The majority of the time, patients are waiting for the tissue to be processed and analyzed. During this time, patients can relax comfortably in the internal lounge or surgical suite. Patients typically bring books to read, work to do, watch a movie or use the office wifi. Most patients are advised to eat before the procedure and can bring snacks for the waiting times.


Yes. Like any surgical 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, reconstruction for optimizing the final functional and cosmetic result becomes the highest priority. Generally, a post-surgical scar improves with time and can take up to 1 year or more to fully mature. 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 laser treatments may be used to optimize the cosmetic result. The physicians at Union Square Laser Dermatology are experts in scar treatments and are available for you throughout the healing process to discuss any concerns that may arise.


Skin cancer treatment should be performed with the highest standards of quality and competence. The American College of Mohs Surgery is the only organization that requires its members to have successfully completed an extensive fellowship that requires at least one full year of training and hands-on experience provided by highly qualified instructors after completing their dermatology residency training. Dr. Chapas and Dr. Chwalek are Fellows of the American College of Mohs Surgery, have each performed thousands of Mohs cases, and instruct dermatology residents in dermatologic surgery at the NYU School of Medicine.


Most insurance plans cover the majority of costs associated with Mohs surgery and reconstruction performed in our office. Our office staff will verify the details of your plan prior to your surgery.


Mohs surgery and reconstruction performed in our office are cost effective in treating skin cancer because of their modest cost (for a surgical procedure), most effective cure rates that prevent re-treatment, and best cosmetic results. When appropriate we will refer reconstruction to a plastic surgeon, which may increase the total cost, and we explain to our patients why that course of treatment may be appropriate in their case. Insurance plans typically cover this when it is for medically necessary purposes. Certain rare situations require surgery in a hospital–for instance this may be necessary when anesthesia is required, such as when operating on the upper or lower eyelid. Such cases are rare (less than 1% of our Mohs patients require in-hospital surgery), but the hospital, operating room, anesthesia and specialized plastic surgery fees can significantly increase the cost. If you should require this type of surgery, it is important to understand in advance what will be covered by your insurance, and our billing staff will assist you in the process.

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