What Is Mohs Surgery?
A Step-by-Step Patient Guide

Mohs micrographic surgery is a specialized skin cancer removal technique that examines 100% of the surgical margin in real time — achieving cure rates up to 99% for primary basal cell carcinoma while sparing the maximum amount of healthy tissue. At Belaray Dermatology in Hicksville and Stony Brook, Long Island, three dual board-certified Mohs surgeons perform the procedure.

What Makes Mohs Surgery Different from Standard Excision?

In a standard excision, the surgeon removes the visible tumor plus a predetermined margin of surrounding tissue. The specimen is then sent to an offsite pathology lab, where a small sample (roughly 1–2% of the margin) is examined. Results return in 1–7 days, and if the margin is positive (cancer cells remain), a second surgery is scheduled.

Mohs surgery eliminates both of those limitations. The Mohs surgeon serves simultaneously as the surgeon and the pathologist. The tissue is processed in an on-site lab, sectioned horizontally (unlike the "bread-loaf" sectioning used in standard pathology), and examined under the microscope by the surgeon. This horizontal technique allows 100% of the peripheral and deep margins to be mapped and visualized before the patient leaves the surgical suite.

Who Is a Candidate for Mohs Surgery?

Mohs surgery is recommended — and is the standard of care — for skin cancers such as basal cell carcinoma and squamous cell carcinoma in the following situations:

• Location on the face, head, or neck — especially around the eyes, nose, ears, lips, and scalp, where tissue preservation is critical for function and cosmesis
• Recurrent tumors — cancers that have previously been treated and returned
• Aggressive histologic subtypes — morpheaform, infiltrative, or micronodular BCC; poorly differentiated SCC
• Large tumors or unclear borders — when the margin is difficult to define visually
• Immunocompromised patients — including organ transplant recipients or those on immunosuppressive therapy
• High-risk anatomic sites — hands, feet, genitals, pretibial leg

How Mohs Surgery Works: Step by Step

1. Local anesthesia is administered

   The treatment area is numbed with a local anesthetic injection. Most patients feel a brief sting; the area becomes fully numb within 60–90 seconds. You will be awake throughout the procedure but should feel no pain. For patients who feel anxious, Belaray offers Pro-Nox™ — patient-controlled nitrous oxide that you breathe on demand and that wears off within minutes, so you can still drive yourself home.

2. The visible tumor is removed (Stage 1)

   The surgeon removes the clinically visible tumor plus a thin margin of surrounding tissue (approximately 1–2mm). The wound is dressed, and you will wait comfortably in the office while the tissue is processed.

3. Tissue is mapped and processed in the on-site lab

   The tissue is divided, color-coded, and precisely mapped — creating a diagram that records the exact location of each tissue section in relation to the wound. The tissue is then embedded in cutting compound, frozen, sectioned into thin horizontal slices, stained, and mounted on slides. This process takes approximately 45–60 minutes per stage.

4. The surgeon examines 100% of the margin

   The Mohs surgeon examines every slide under the microscope. If cancer cells are present at any margin, their exact location is marked on the map. This allows the surgeon to precisely target only the area of positive margin in the next stage — removing no more healthy tissue than necessary.

5. Additional stages are taken only where needed

   If cancer remains, another thin layer is removed exclusively from the involved area and the process repeats. Approximately 80% of Mohs cases are cleared in one or two stages. Once the margins are clear — confirmed by the surgeon under the microscope — the procedure is complete.

6. Reconstruction of the surgical wound

   Once the tumor is fully removed, the wound is repaired. Depending on size and location, repair options include: allowing the wound to heal on its own (second intention), simple linear closure, a local skin flap, or a skin graft. For complex facial or periocular defects, Belaray's oculofacial plastic surgeon performs same-day oculoplastic reconstruction — a capability unique to Belaray in the Tri-State Area.

What to Expect After Mohs Surgery

Recovery timeline

Most patients resume normal activities within 24–48 hours. Strenuous activity and heavy lifting should be avoided for 1–2 weeks depending on location. Sutures are typically removed 7–14 days after the procedure. Redness, swelling, and bruising in the first 5–7 days are normal.

Scarring

Mohs surgery is designed to minimize scarring by preserving as much healthy tissue as possible. The appearance of the scar depends heavily on location, wound size, and the reconstruction technique used. Most scars fade significantly over 12–18 months. Belaray's cosmetic and laser services — including CO₂ fractional laser resurfacing and RF microneedling — are available for scar revision after healing is complete.

Follow-up and surveillance

A history of skin cancer increases your lifetime risk of developing additional skin cancers. Belaray recommends regular follow-up skin exams — typically every 6–12 months for the first 5 years after a Mohs procedure, then annually. Your provider will discuss a personalized surveillance schedule at your post-operative visit.

The Three Mohs Surgeons at Belaray Dermatology

Belaray Dermatology has three dual board-certified Mohs surgeons — Dr. Jeffrey Ellis, Dr. Dana Baigrie, and Dr. Anthony Wong — each board-certified by the American Board of Dermatology in Dermatology and Micrographic Dermatologic Surgery. Drs. Ellis and Wong are fellowship-trained in Mohs micrographic surgery, and Dr. Wong is a Fellow of the American College of Mohs Surgery (FACMS).

Co-founder Dr. Jeffrey Ellis established Belaray's Mohs surgery program in 2006 and has performed thousands of Mohs procedures over his two-decade career at the practice.

Frequently Asked Questions