Mohs Micrographic Surgery

What Is Mohs Surgery?

Mohs micrographic surgery is a precise surgical technique developed by Dr. Frederic Mohs in the 1930s and refined over decades into the definitive treatment for the most common skin cancers. Unlike standard excision — which removes a visible tumor plus a margin of surrounding tissue and sends it to an outside laboratory — Mohs surgery keeps the surgeon and the laboratory in the same room, allowing real-time microscopic examination of every excised tissue layer.

The result is the highest possible cure rate combined with the most conservative removal of healthy tissue — a combination that is especially important on the face, where preserving normal skin is critical for both function and appearance.

How Mohs Surgery Works — Step by Step

1. 1

   Anesthesia

   The area around the tumor is injected with local anesthetic. You remain fully awake and comfortable throughout the procedure.

2. 2

   Removal of the visible tumor

   The surgeon removes the visible lesion along with a thin layer of surrounding tissue using a scalpel. A temporary bandage is placed over the wound.

3. 3

   Tissue mapping and processing

   The removed tissue is divided into precisely mapped sections. Each section is color-coded so the surgeon can track its exact location on the wound. The tissue is then frozen, cut into thin slices, and stained by the on-site histotechnician.

4. 4

   Microscopic examination

   The Mohs surgeon examines 100% of the undersurface and margins of the removed tissue under a microscope — examining the entire surgical margin rather than the 1–2% sampled by standard pathology.

5. 5

   Additional stages if needed

   If cancer cells are found at any margin, the surgeon returns to the patient, removes another thin layer only from the precise area where cancer remains, and repeats the process. This cycle continues until the entire margin is clear.

6. 6

   Wound closure

   Once the cancer is confirmed fully removed, the wound is closed the same day using the most appropriate technique for that location.

Cure Rates

Mohs surgery achieves the highest cure rates of any skin cancer treatment method:

• 98%+ five-year cure rate for primary (never treated) basal cell carcinoma
• 94%+ five-year cure rate for primary squamous cell carcinoma
• Up to 94% cure rate for recurrent BCC (compared to ~83% for standard re-excision)
• Lower recurrence rates than standard excision, radiation, or topical therapy

Who Is a Good Candidate for Mohs Surgery?

Mohs surgery is recommended when tissue preservation and complete margin control are critical. Ideal candidates include patients with:

• Basal cell carcinoma or squamous cell carcinoma on the face, head, neck, hands, or feet
• Tumors near cosmetically or functionally important structures (eyelids, nose, lips, ears)
• Large tumors (>2 cm) or tumors with poorly defined borders
• Aggressive subtypes such as morpheaform/sclerosing BCC or poorly differentiated SCC
• Recurrent cancers that have been treated before with other methods
• Tumors in sites with high recurrence risk such as the nose and ear
• Immunosuppressed patients who require the most reliable clearance

Reconstruction After Mohs Surgery

After the cancer is cleared, the wound is repaired the same day. The reconstruction method depends on the size and location of the defect and the patient's overall health. Options include:

• Linear closure — simple side-to-side stitching for smaller defects in low-tension areas
• Local flap repair — adjacent skin is repositioned to cover the defect, providing excellent color and texture match
• Full-thickness skin graft — skin from a donor site (often behind the ear) is transplanted to cover larger defects
• Secondary intention healing — for small wounds in certain locations, allowing the wound to close naturally with a good cosmetic outcome

Our Mohs surgeons perform the reconstruction themselves, eliminating the need for a separate plastic surgery referral in most cases.

Recovery

Recovery from Mohs surgery is typically straightforward. Most patients can resume light daily activities the day after the procedure. Here is what to expect:

• Mild swelling, bruising, and tenderness at the surgical site for 1–2 weeks
• Keep the wound clean and moist with antibiotic ointment and a bandage as directed
• Sutures removed at a follow-up visit, usually 7–14 days after surgery depending on location
• Avoid strenuous activity and heavy lifting for 2–4 weeks
• Scar appearance continues to improve over 6–12 months
• Sun protection over the scar is essential to minimize pigmentation changes