How Mohs Surgery Works
How Mohs Surgery Works
Mohs Micrographic Surgery is a precise, highly effective technique for removing skin cancer while preserving as much healthy tissue as possible. During the procedure, Dr. Pennie removes the visible tumor along with a thin margin of surrounding tissue, which is then processed and examined under a microscope in our onsite lab, all on the same day. If cancer cells are detected at the margins, only that specific area is addressed, and the process repeats until the margins are completely clear. This layer-by-layer approach allows Dr. Pennie to trace and remove the cancer with exceptional accuracy, resulting in the highest cure rates available for skin cancer while minimizing impact to the surrounding skin.
Before the Procedure Begins
Your Mohs surgery takes place right here at Bliss Dermatology + Wellness. There is no need for a hospital or a separate surgical facility. Dr. Pennie performs the procedure in our office, and our onsite Mohs lab processes and examines your tissue immediately, with no waiting for results from an outside laboratory required. When you arrive, our team will get you settled and make sure you are comfortable. We will review the site with you, answer any last questions, and walk you through exactly what the day will look like before anything begins.
Step One: Mapping the Tumor
The procedure begins with our team carefully examining and mapping the area to be treated. The tumor is marked to create a precise reference point, a kind of topographic guide that will be used throughout the procedure to track exactly where tissue has been removed and where the margins stand at each stage. This mapping is a critical foundation. It ensures that every layer removed can be accurately oriented and examined, and that if additional tissue needs to be taken, Dr. Pennie knows exactly where to focus.
Step Two: Local Anesthesia
The treatment area is numbed with a local anesthetic. You will be fully awake throughout the procedure as Mohs surgery does not require general anesthesia, but you will not feel pain at the surgical site. Most patients are comfortable and relaxed once the area is numb. Our team will check in with you regularly, and your comfort is always a priority.
Step Three: Removal of the First Layer
Once the area is numb and mapped, Dr. Pennie removes the visible tumor along with a very thin margin of surrounding tissue. This margin is intentionally narrow, Mohs surgery is specifically designed to take as little healthy tissue as possible at each stage. A temporary bandage is placed over the wound, and you will move to our comfortable waiting area while the tissue is prepared in our onsite lab.
Step Four: Processing in Our Onsite Lab
This is where Mohs surgery is fundamentally different from standard excision. In a standard excision, a wider margin of tissue is removed all at once and sent to an outside lab. Results may take days. And critically, only a small percentage of the total margin is actually examined, meaning there is a chance that remaining cancer cells go undetected. With Mohs surgery, the removed tissue is taken directly to our onsite lab and processed immediately. It is divided, color-coded to preserve its orientation, and prepared into slides that allow Dr. Pennie to examine 100% of the surgical margin under a microscope.
Step Five: Microscopic Examination
Dr. Pennie examines every slide carefully under the microscope, reviewing the full margin of the removed tissue for any remaining cancer cells. If the margins are clear, meaning no cancer cells are detected at the edges of the removed tissue, the procedure is complete. The cancer has been fully removed. If cancer cells are found at any margin, Dr. Pennie notes precisely where on the map they appear. Only that specific area will be addressed in the next stage. Healthy tissue surrounding clear margins is left entirely untouched. This targeted approach is what makes Mohs surgery so uniquely tissue-sparing. Rather than removing a wide, uniform margin around the entire tumor, Dr. Pennie follows the cancer exactly, removing only what needs to be removed, and nothing more.
Step Six: Additional Layers, If Needed
If cancer cells remain, Dr. Pennie returns to the treatment area and removes another thin layer of tissue where cancer was detected. A new bandage is placed, and you return to the waiting area while the new tissue is processed and examined. This cycle repeats as many times as necessary. Each stage is guided by the microscopic findings of the stage before it. Most patients require two to three stages, though this varies depending on the size, type, and growth pattern of the cancer. The process continues until Dr. Pennie confirms that all margins are completely clear.
Step Seven: Wound Closure
Once clear margins are confirmed, attention turns to closing the wound. The approach to closure depends on the size and location of the wound, as well as the characteristics of the surrounding skin. Dr. Pennie will choose the method most likely to achieve both optimal healing and the best cosmetic result. Simple closure involves bringing the edges of the wound together with sutures. This is the most straightforward option and is used when the wound is small enough to close directly. A flap involves repositioning nearby skin to cover the wound. This technique is used when direct closure would create too much tension or distort the surrounding tissue. A skin graft uses skin taken from another area of the body to cover a wound that cannot be closed by the surrounding tissue alone. Grafts are typically used for larger wounds or wounds in areas with limited surrounding skin. Whatever the approach, the goal is always the same: a well-healed wound and the best possible outcome for you.
Bliss Dermatology + Wellness Onsite Mohs Surgery Lab
At Bliss Dermatology + Wellness, our Mohs surgery patients benefit from the convenience and efficiency of a fully equipped onsite lab. Rather than waiting days for results from an outside facility, your tissue is processed and examined right here in our office, keeping your procedure moving efficiently and reducing the time you spend in our care. We also provide a comfortable, dedicated waiting area exclusively for Mohs patients, so you can relax between stages in a calm, private setting. From start to finish, our goal is to make your experience as seamless and stress-free as possible.
If you have been diagnosed with basal cell carcinoma, squamous cell carcinoma, or melanoma in situ, we encourage you to schedule a consultation with our team. We will review your case, answer your questions, and help you understand whether Mohs surgery is the right path forward.