Flint Dermatology and Dermatologic Surgery Center


2256 West Hill Road • Flint, MI 48507 • (810) 249-7546

Our Mohs Surgeon

Dr. Aaron Cetner is a specialist in skin cancer surgery, having completed a fellowship in cutaneous oncology certified by the American College of Mohs Surgery. His expertise includes the treatment of basal and squamous cell carcinomas, malignant melanoma, and other rare skin tumors, as well as aesthetic reconstruction following tumor removal. Dr. Cetner performs approximately 1,200 cases of Mohs surgery per year. He is a Fellow of the American College of Mohs surgery, a member of the American Society for Dermatologic Surgery, and a Fellow of the American Academy of Dermatology.



Understanding your diagnosis.

Skin cancer is the most common form of all cancer, with approximately 3.5 million cases diagnosed annually in the United States. The majority of these are non-melanoma skin cancers, including basal and squamous cell carcinoma. Approximately 70,000 cases of malignant melanoma, the most dangerous skin cancer, are diagnosed annually.

Non-melanoma skin cancers favor sun-exposed areas, especially the head and neck. Both cumulative (lifetime) and acute (recent) sun exposure are involved in their development. Because a skin cancer may grow for several months before becoming apparent, the true size may not be fully appreciated on the skin surface. It is extremely rare for a basal cell carcinoma to spread (metastasize) to another location in the body. However, basal cell cancers can cause skin breakdown and bleeding, and if left untreated may invade underlying cartilage, bone, or nerves. Squamous cell carcinomas may demonstrate more rapid growth and a small risk of metastasis. 

Mohs Microscopically Controlled Surgery: Removing the bad. Sparing the good.

Mohs microscopically controlled surgery was developed in the 1940s by Dr. Frederick Mohs. In a standard excision, a wide margin of tissue is removed around the visible tumor and sent to a pathologist for examination. In contrast, the Mohs surgeon takes a much narrower margin (typically 1 millimeter or so) around the tumor. This saucer-shaped specimen is processed in an on-site lab. The Mohs surgeon then uses a microscope to map the extent of any tumor in this specimen. If tumor is present, a second piece of tissue, or “layer,” is taken for examination. The process is repeated until a margin of cancer-free tissue is achieved. In this way, the Mohs surgeon achieves a 99% cure rate while sacrificing the smallest amount of healthy tissue.

Mohs surgery is reserved for the treatment of non-melanoma skin cancers in particular situations. This includes tumors in cosmetically or functionally important areas such as the face, aggressive tumors, those with poorly defined edges, or tumors that have reoccurred after a previous treatment. Mohs surgery is not employed for the treatment of malignant melanoma.

Preparing for your Mohs surgery.

We recommend eating breakfast and taking all of your regular medications the morning of surgery. Unless directed by your physician, please do not take aspirin, Vitamins E or C, or Gingko Biloba for one week prior to surgery. Alcohol may increase your risk of bleeding and should be stopped at least 3 days prior to and after surgery. Cigarette smoking can impair healing, and should be stopped or significantly reduced for at least one week prior to and after surgery. In general, pre-operative antibiotics are only required if you have had a joint replacement within 6 months of your surgery date, or if you have had a heart valve replaced or suffered rheumatic fever in the past. Nevertheless, please inform our staff prior to your surgery day if you have a pacemaker or defibrillator, artificial joint, artificial heart valve, congenital heart disease, diabetes, or take antibiotics prior to dental procedures.

What to expect on the day of surgery.

You should arrive for your appointment 15 minutes early in order to complete any registration requirements. Mohs surgery may take as little as one or two hours or as much as the entire day, depending on the number of layers required. Please bring something to occupy your time, such as reading material or a music player. We offer a comfortable, private waiting room with television, coffee, and some small snacks. However, because the surgical day can potentially be long, you may want to bring something with to eat. You should arrange for a driver if you are anxious about the surgery, of if the surgery will involve the area immediately around the eyes. 

The surgical site will then be numbed with a local anesthetic. Removal of the initial layer of tissue typically takes 5 minutes, after which a temporary dressing will be placed on the wound. Tissue processing may take 30 to 45 minutes, during which time you are free to relax. Your surgeon will review the processed specimen under a microscope, and create a map of any residual tumor present. If necessary, subsequent tissue specimens (“layers”) are removed, processed, and mapped until the entire skin cancer is removed.

After the tumor has been completely removed, your surgeon will determine the best method to repair the wound. Wounds are occasionally allowed to heal on their own. More often, however, the wound will be closed with stitches in a straight-line fashion or using a skin flap or skin graft. Most wounds are repaired in our office on the day of surgery. It is rarely necessary to consult other surgical specialists and arrange reconstruction for a subsequent day.

What to expect after surgery.

Detailed, wound care instructions will be provided to you. All wounds are initially dressed with a bulky pressure bandage that must be kept dry and intact for 2 days. Thereafter, once daily wound care is continued until the stitches are removed (usually 7 to 14 days after surgery). 

Your physical activity will be limited for at least a week (and up to two weeks for some surgical sites) after surgery, including heavy lifting, running, and working out. Please make appropriate arrangements for work.

Most patients have minimal discomfort after surgery, and we recommend over-the- counter Tylenol (Acetaminophen) for pain. Because Ibuprofen may cause an increase in bleeding with larger surgical sites, your surgeon will advise you whether its use is permissible.

Swelling and bruising are variable depending on the individual and surgical site. If surgery is done in close proximity to the eyes, lower forehead, or upper nose, some bruising and swollen eyelids should be anticipated.


Every surgical procedure will produce some form of a scar. Although every attempt will be made to minimize and camouflage the scar, the extent of scarring depends on the location, size and depth of the skin cancer, as well as the healing properties of the patient. Scars improve naturally with time, and additional therapies for scar refinement are available.

Follow Up and Prevention.

Unfortunately, a skin cancer diagnosis carries with it an increased risk for additional skin cancers. Your general dermatologist is best equipped to help you in monitoring your skin. Examinations should be scheduled every 6 months for one year after treatment, and at least annually thereafter.

Please visit www.skincancermohssurgery.org for more information. Also, please contact our office for any questions you may have.

Preparation for Mohs Surgery—Frequently Asked Questions

Should I arrive earlier than my scheduled appointment time?
Yes. 15 minutes ahead of your scheduled time is advised in order to complete the registration process.

What papers should I bring with me?
A list of your medications, insurance card(s) and Medicare card (if applicable), and a photo ID

How long will my procedure take?
It is not possible for us to estimate this at the outset. It may require as little as 1 or 2 hours, or you might be at the office for the entire day. For this reason, we advise patients to not schedule any other appointments or engagements the day of surgery.
Although most skin cancers are cleared in 1 or 2 stages of Mohs surgery, it is impossible to predict those that will require more stages. Similarly, certain locations may require a more complex, and thus more time-consuming, reconstruction.

May I have breakfast and take my medicine(s) before surgery?
You should eat a good breakfast, especially if you are a diabetic

What type of anesthesia will I have?
We use only local anesthesia. No general anesthesia or IV sedation is used.

Should I have a driver?
You must have someone drive if your skin cancer is around/near your eye. The dressing you wear home may block your vision.

What if the skin cancer is not near my eye?
It is up to you if you want a friend/family member to do the driving. However, it is always a good idea to have someone to call if the need arises.

I am very anxious about the procedure? Do you have medicine to help me relax?
Yes, we are able to administer oral Ativan (Lorazepam) on the day of surgery. However, you MUST have a driver in order to use this medication.

Is it true that smoking increases the likelihood of complications following surgery?
Yes, smoking does impair wound healing. Although we do not expect patients to quit smoking, decreasing the amount smoked (ideally to less than 1 pack per day) for 7 days before surgery and 2 weeks after surgery is recommended.

I am on oxygen. Do you have oxygen available if I run out?
We do not have oxygen available. It is your responsibility to have enough oxygen available for the duration of the day.

Should I stop taking any medicines?
There are many non-prescription (over the counter) medicines that thin the blood. Please stop these 7 days before surgery.
Vitamin E (A multi-vitamin that contains Vitamin E is permissible)
Gingko Biloba

What about alcoholic beverages?
Alcohol can also thin the blood. Please stop alcoholic beverages for at least 3 days before and after surgery.

What should I take if I have a headache/muscle or joint aches?
You may take Tylenol if needed. If you have arthritis for which daily ibuprofen or naproxen is essential, it is permissible to use this prior to surgery.

I am taking Aspirin. Should I stop this?
In general, if you are taking Aspirin for primary prevention (e.g. you have never had a heart attack, stroke, blood clot, etc), then you may discontinue it. If you are taking Aspirin for a medical condition, you must check with your prescribing doctor prior to discontinuation. Please check with your prescribing doctor if you are unsure.

My doctor has me on Coumadin. Should I stop this?
No. Continue to take this as prescribed. However, we do recommend that you check with the prescribing/monitoring physician to make sure your blood is within the therapeutic level (called the “INR”). This should be done within the two-week period prior to your surgery.

Should I stop Plavix? (or other blood-thinning medication such as Xarelto, Eliquis, or Pradaxa)
In general, we do not discontinue these medications prior to surgery. These medications are often taken for serious conditions, and stopping them may pose a greater risk than the potential for bleeding after our surgery. I have had a joint replacement procedure in the past. Do I need antibiotics prior to surgery? In general, if your joint surgery was performed in the past 6 months, pre-operative antibiotics are required. If your joint surgery was performed over 6 months ago, they are not required. Please contact the office to obtain a prescription prior to surgery if appropriate.

Do you have a coffee machine?
Yes. Our Mohs waiting room has coffee and small snacks provided.

Is it okay to bring food with me?
Please bring snacks or a lunch with you. You may potentially be in the office for a significant portion of the day.

Can I leave the office to grab a bite to eat or a cup of coffee?
It is preferable that you remain in the office, as we may be ready to take another Mohs layer or repair your surgical site on short notice.

What kind of bandage will I be leaving with?
You will go home with a bulky dressing over the surgical site(s) that we ask you to leave on for 48 hours.

Can I go to work the day after my surgery?
This depends on the recommendation of the doctor. We are happy to provide a work excuse if necessary.

Can I workout, run, play sports, or do heavy lifting after surgery?
No. We ask you to refrain from strenuous activities for several days, and up to 1-2 weeks, following surgery. This is important as to minimize complications and bleeding, and to ensure optimal healing.

My skin cancer is on my lower leg. Will I be able to walk around after surgery?
Due to tension on lower leg surgical sites, we recommend that you are off your feet as much as possible following surgery. Walking for necessities is permissible, but extended distance walking for pleasure (e.g. exercise, hiking, a trip to New York) is not recommended for two weeks following surgery.

Will I be bruised or have any swelling?
Yes. Although this varies considerably among patients, assume that you will have bruising and swelling for a week or longer. The site of surgery as well as your activity level contributes to the amount of bruising and/or swelling you may have.

Will I need to do any wound care to the surgical site(s)?
Yes. A detailed wound care sheet will be sent home with you.

If you have additional questions, please do not hesitate to contact our office at (810) 249-7546

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