Mohs’ Micrographic surgery to treat skin cancer

Your doctor has recommended micrographic surgery to remove your skin cancer. This leaflet explains what the procedure involves as well as its risks and benefits. If you have any questions or concerns, please speak to a doctor or nurse caring for you.

What is micrographic surgery?

This is a specialised form of surgery to remove certain skin cancers (tumours) and is called Mohs’ surgery (Mohs is the name of the doctor who developed it). Your surgeon removes the visible portion of your tumour and then removes further tissue that may contain cancer cells, one layer at a time. This tissue is examined under a microscope while you are still in the dermatology unit. If it contains cancer cells, another layer of tissue is removed and examined. This is repeated until all the cancer cells have been removed, which may last several hours.

Your doctor may have recommended Mohs’ surgery because:

  • Your skin cancer has returned;
  • Your tumour was previously removed, but some cancer cells remain;
  • Your cancer is in an area where we want to reduce the amount of healthy tissue we remove, such as on your eyelids, nose, ears or lips; or
  • The edges of your tumour are not well defined.


Why should I have micrographic surgery?

Other types of surgery for skin tumours rely on the surgeon being able to see the extent of the cancer. This can sometimes lead to a large wound and scar if too much healthy tissue is removed. It could also lead to too little tissue being removed and the cancer returning.

Micrographic surgery maximises the chances of your tumour being completely excised (removed) while minimising the amount of surrounding normal skin that needs to be taken away.


Are there any other alternatives?

Your doctor has recommended that this is the most appropriate treatment for you. Any alternatives will have been discussed at your consultation. If you have further questions please see the contact details overleaf.

If your skin cancer is not treated, it will continue to grow and you may need more aggressive treatment in the future.


How can I prepare for my surgery?

Please do not wear any make up or jewellery on or near the site of your surgery. You may want to bring a packed lunch with you on the day of the surgery, as you may be here for several hours.

We strongly suggest that you bring a friend or family member with you. We strongly recommend that you do not travel home by public transport and you should not, under any circumstances drive yourself on the day of your surgery.


Asking for your consent

We want to involve you in all the decisions about your care and treatment. If you decide to go ahead with this surgery, you will be asked to sign a consent form. This confirms that you agree to have the procedure and understand what it involves.


What happens during Mohs’ surgery?

There are several stages to Mohs’ surgery. First, your doctor will inject the area where your tumour is, with a local anaesthetic. This numbs the area, so you will not feel any pain during surgery and will remain awake. If you are particularly anxious, we can give you a mild sedative to help you relax. Please discuss this with your doctor. We may also use anaesthetic eye drops if the tumour is near your eye.

Once the anaesthetic has taken effect, the visible (also called the clinically evident) part of the tumour is removed, along with a small margin of normal skin tissue. This tissue is taken to a laboratory where your doctor will be able to look at it under a microscope to check for cancer cells. This takes about 40–60 minutes, so a temporary dressing is applied to your wound and you are asked to sit in a waiting area.

If cancer cells are present in this tissue, you will be brought back into theatre and more tissue will be taken away and examined under the microscope. This will be repeated until all the tumour cells have been removed.

The local anaesthetic lasts for about two hours and can be ‘topped up’ if your surgery takes longer than this. Because of the nature of this procedure, we are unable to tell you exactly how long your surgery will last.


What happens after the procedure?

After completion of your Mohs surgery, a dressing will be placed onto the wound and you will need to follow the instructions given by your referring surgeon regarding where to attend for repair.


What are the risks?

Your doctor will explain the potential risks for this type of surgery with you in more detail, but complications include:

  • Bleeding at the site of the tumour.
  • Pain. The local anaesthetic should last until you return home. If you need to, you can buy aspirin-free pain relief (such as paracetamol) from a chemist without a prescription. Always check that the painkillers will not react with any other medication you are taking and follow the instructions on the packet. The doctor or nurse caring for you can give you more advice.
  • Nerve damage. Although your surgeon will try to avoid this, nerves can occasionally be damaged during surgery, leading to a numb area of skin. This is usually temporary.
  • Infection at the wound site. You will be given instructions on how to care for your wound to minimise this risk.
  • Scarring. You will have a scar after the surgery, although the doctors use closure techniques to minimise this. Scars fade over time.


Will I have a follow-up appointment?


You will have a follow-up appointment with the team that repaired your wound.

Other sources of support or information

  • Macmillan Cancer Support (freephone)
  • t: 0808 808 0000 (for information on all aspects of cancer)
  • t: 0808 801 0304 (benefits enquiry line)
  • w:

Cancer Research UK (freephone)

t: 0808 800 4040 (for information on all aspects of cancer)



The Face Surgeons