Mohs surgery is a specialized skin cancer treatment that removes thin layers of cancerous tissue and examines them under a microscope during the same appointment, continuing layer by layer until no cancer cells remain. Mohs surgery is suitable when precise removal is needed to preserve healthy tissue, especially for basal cell and squamous cell carcinomas on the face, ears, nose, eyelids, lips, scalp, hands, feet, and other sensitive areas.
At Regency Specialties, Mohs surgery is part of a broader treatment program that also includes full-body screening, treatment of precancerous actinic keratosis, and reconstructive options.
Mohs micrographic surgery is named after Dr. Frederic E. Mohs, the physician who developed the technique in the 1930s. It has been refined for decades and is now considered the reference standard for treating many common skin cancers, especially those in cosmetically and functionally sensitive locations.
What makes Mohs different is timing. With most excisions, tissue is removed, sent to an outside lab, and results come back days later. With Mohs surgery, the tissue is processed and reviewed under a microscope during your visit – so you know before you go home whether the margins are clear.
The result is a treatment that is both thorough and conservative. Cancer is tracked to its edges, and normal skin surrounding it is left alone whenever possible. On a nose, eyelid, or upper lip, millimeters matter.
Skin cancers are often compared to icebergs. What you see on the surface – a scaly patch, a pearly bump, a sore that keeps scabbing over – may represent only part of the growth, with roots extending sideways or downward in unpredictable patterns.
Mohs surgery addresses that uncertainty by combining removal and microscopic mapping into one process:
Targeted removal. The surgeon removes the visible tumor plus a very thin margin of surrounding tissue.
Detailed mapping. The tissue is color-coded with dyes to create a map corresponding to its exact location on your body.
Microscopic analysis. The tissue is frozen, sliced into horizontal sections, stained, and examined. The surgeon acts as their own pathologist, checking the entire bottom surface and outer edges.
Pinpoint accuracy. If cancer appears at one edge, its location is marked on the map, and only that specific area is treated further. Clear areas are left undisturbed.
Completion. The cycle repeats until a layer is completely free of cancer.
This is why Mohs is described as “micrographic.” The surgeon is not estimating margins – they are reading them directly and treating only where evidence shows cancer remains.
Traditional excision remains an excellent option for many skin cancers, particularly small, well-defined lesions on the trunk, arms, or legs. The visible tumor is removed with a predetermined margin, the specimen goes to an off-site lab, and a report typically arrives within several days.
The differences that matter most to patients:
Margin certainty. Mohs surgery examines 100% of the surgical margin and confirms clearance the same day. Traditional excision typically examines only a small fraction – around 1–3% – through vertical slicing, and a positive margin means a second procedure.
Tissue conservation. A fixed margin often removes more healthy skin than strictly necessary. Mohs surgery removes tissue based on what the microscope shows, which usually means a smaller final defect – crucial on the face, hands, or scalp.
Reconstruction planning. With Mohs surgery, the wound is closed after margins are confirmed clear, so the repair is planned around a known, final size.
Neither approach is universally superior. The right choice depends on tumor type, size, location, and your overall health.
Mohs surgery is used most frequently for the two most common forms of skin cancer:
Basal cell carcinoma (BCC). The most common skin cancer overall. BCCs rarely spread to other organs but can invade nearby tissue if untreated.
Squamous cell carcinoma (SCC). The second most common type, and more aggressive in some cases, with greater potential to spread if neglected. SCCs on the ear, lip, or scalp, those that are large or aggressive, and those in patients with weakened immune systems are often treated with Mohs.
Mohs may also be considered for less common tumors, including rare skin cancers that extend beyond their visible borders and selected cases of melanoma in situ using specialized techniques. A thorough skin cancer screening is the first step in identifying suspicious lesions and determining the need for biopsy.
Our dermatology providers in Phoenix, Surprise, and other locations evaluate each case individually against these criteria:
Location. The nose, eyelids, ears, lips, eyebrows, temples, face, scalp, neck, hands, fingers, feet, toes, and genitals are classic Mohs sites.
Size and borders. Tumors larger than roughly 2 cm on the body or 1 cm on the face, or with edges that fade into surrounding sun-damaged skin, benefit from margin mapping.
Recurrence. Cancers that return after previous treatment often have scar tissue mixed in, making borders hard to judge.
Biopsy findings. Aggressive growth patterns on pathology, or evidence that a tumor is tracking along nerves, favor Mohs surgery.
Patient factors. A suppressed immune system (organ transplant, leukemia), prior radiation to the area, or a genetic condition causing multiple skin cancers all shift the recommendation toward Mohs.
Professional appropriate-use criteria guide these decisions, and your provider will explain which factors apply to your case.
Mohs is not necessary for every skin cancer.
Superficial lesions well suited to topical therapy or curettage
Most invasive melanomas, which typically require wide local excision and, in certain cases, lymph node evaluation – melanoma cells can be harder to identify in frozen sections
Some tumors are extensive enough that a different surgical approach or additional oncologic care is more appropriate. A thorough evaluation sorts this out before anything is scheduled.
Mohs surgery is an outpatient procedure performed under local anesthesia – you stay awake, and general anesthesia is rarely needed. You will review medications, allergies, and health history with your provider. Blood thinners are often discontinued, but that decision belongs to your prescribing physician and your surgeon together – never stop a medication on your own.
Practical advice from patients who have been through it:
Plan for a longer appointment than you expect; much of the time is spent waiting while tissue is processed.
Bring a book, tablet, or headphones to occupy you between stages.
Eat a normal breakfast unless told otherwise, and bring a snack.
Wear a button-front or zip-front shirt if the site is on your head or neck.
Arrange a ride if the site is near your eye or you get lightheaded during procedures.
Afterward, you will have a bandage in place, written wound care instructions, and a follow-up plan. Most people go home the same day and resume light activity right away.
Anesthesia and preparation. The area is cleaned, and a local anesthetic is injected to numb it completely.
Removal of the first layer. The surgeon removes the visible tumor with a scalpel plus a thin underlying layer of tissue, and a temporary bandage is placed.
Lab processing and mapping. In the on-site lab, a technician freezes the tissue, cuts it into thin horizontal slices, stains them, and maps them to your surgical site.
Microscopic examination. The surgeon examines 100% of the tissue margin for remaining cancer cells.
Repeating the process. If cancer is found, the surgeon uses the map to locate it, re-numbs that spot if needed, and removes another thin layer only from that area.
Completion. The cycle repeats until a layer shows no evidence of cancer.
Removing each layer takes only a few minutes, but lab processing and microscopic examination of each layer takes roughly 45–60 minutes. Total clinic time typically ranges from two to six hours – occasionally longer if reconstruction is needed. Because no one can predict the number of stages in advance, clear your schedule for the day.
You should not feel pain during surgery beyond a pinch or brief burning when the anesthetic is injected. Most patients describe their sensations after the procedure as mild to moderate – closer to a bruise or deep scratch – with soreness peaking the first day or two.
Here are some aftercare tips:
Elevate. For face or scalp sites, sleep with your head slightly raised to reduce swelling.
Ice as directed. Short intervals of cold over the dressing help in the first 24 to 48 hours.
Expect some bruising. Facial sites, especially near the eyes, bruise more than patients anticipate; it typically resolves within a week or two.
Take it easy on exercise. Heavy lifting, bending, and vigorous workouts are paused for a period your provider recommends.
Follow medication guidance. Over-the-counter pain relievers are usually sufficient; your provider will advise what’s appropriate.
Swelling and tightness are normal early signs of healing, not signs that something has gone wrong.
Good wound care makes a visible difference in the final result and in minimizing scarring. Instructions vary by wound type and location, but the principles are consistent:
Keep the dressing clean and dry for the period your provider specifies, and change it as instructed.
Clean the site gently and apply the recommended ointment – moist wounds heal with less crusting.
Do not pick at scabs or trim sutures yourself.
Watch for signs of infection and report them promptly.
Protect healing skin from the sun. That means a wide-brimmed hat, shade, and diligent sunscreen once the wound has closed.
Attend your suture-removal and follow-up visits.
Scars continue to mature for many months. What looks pink and firm at six weeks often softens and fades substantially over the following year. Regency Specialties provides ongoing wound care support so you are not managing this alone.
Sometimes. Once margins are confirmed clear, the size and location of the final wound determine the repair method:
Natural healing – letting the wound heal on its own
Simple sutures – closing the wound in a straight line
Skin flap – moving adjacent skin to cover the wound
Skin graft – taking skin from another area to cover the wound
Larger defects, or those in delicate areas like the nose, eyelid, ear, or lip, are more likely to need a flap or graft.
Regency Specialties offers skin cancer care across the West Valley, with locations in Phoenix and Surprise. To discuss a biopsy result or schedule an evaluation, call (623) 243-9077 or fill out a short form on our website.
Mohs surgery offers one of the most effective ways to treat many common skin cancers while preserving as much healthy tissue as possible. If you’ve been diagnosed with basal cell or squamous cell carcinoma – or have a suspicious skin lesion – early evaluation can make a significant difference. The experienced dermatology team at Regency Specialties will help you determine whether Mohs surgery or another treatment option is right for your specific needs and guide you through every step of your care.
About the Author
Nicholas Stanzione
July 27, 2026
