What is Mohs Surgery?

Mohs surgery (also called Mohs Micrographic Surgery) is named after its founder, Dr Mohs, who founded the technique of Mohs surgery in the 1930s.

Mohs surgery, unlike ‘conventional surgery’, performs the laboratory tests on the same day as removal of the basal cell carcinoma. This results in a higher cure rate, and is often seen as the treatment of choice for a number of basal cell carcinomas.

How is Mohs Surgery performed?

The first steps of Mohs surgery are similar to ‘conventional surgery’. Whilst Mohs surgery can occasionally be performed under general anaesthetic (ie, with you asleep), it is usually performed under local anaesthetic (an injection is used to numb the skin). The basal cell carcinoma is then cut out, but unlike conventional surgery, only a minimal margin of ‘normal looking’ skin is also taken.

The wound is then dressed with a sterile dressing and the BCC is taken into the lab and processed to produce slides that can then be checked under a microscope. Mohs maps have also been drawn of where the basal cell carcinoma came from.

When the slides are checked, the Mohs surgeon is looking for any evidence of basal cell carcinoma that hasn’t been fully removed. If any is found, then the location can be drawn onto the map, so the Mohs surgeon can then tell whereabouts on the wound there might be the remaining basal cell carcinoma.

The skin is then numbed again, and a further thin layer is removed, but only from where the remaining basal cell carcinoma is. The wound is dressed, slides rechecked, and the process is repeated until the basal cell carcinoma has been cleared.

The wound can then be fixed which, depending on the location, size and shape of the wound, may need various reconstructive techniques. These include simple stitching of the wound, moving in skin from nearby (local flap), skin grafting, or even more complex techniques.

Whilst many Mohs surgeons (who are Dermatologists) can perform simple reconstruction, more complex procedures may require a specialist such as a Plastic surgeon, which may mean a wait of a day or two before your wound is fixed. It is also common for patients (especially in the USA) to ask to have a Plastic surgeon repair their wound, regardless of size.

Occasionally, a Mohs surgeon may have had further training in reconstruction, or even rarely be from a Plastic surgery background (such as Mr Tehrani), so can provide specialist reconstruction themselves.

What are the advantages of Mohs surgery?

When the slides are checked in Mohs surgery, the entire skin edge and deep margin are checked, unlike in ‘conventional surgery’ where only a small proportion of the edges are seen. This way, every part of the basal cell carcinoma can be chased out, which gives a 5-year cure rate of 99% for Mohs surgery (as opposed to 90-95% for conventional surgery).

Also, conventional surgery usually takes at least a 3-4mm margin of ‘normal looking’ skin with the basal cell carcinoma, in case any ‘roots’ are unseen within the skin. In Mohs surgery though, only the tissue with basal cell carcinoma is removed. This means that, occasionally, more healthy skin is kept and the wound may be smaller than with conventional surgery. This can result in smaller scars, or even change the reconstruction needed.

For more information, please see our sister site mohs-surgeon.co.uk

This information is provided for general knowledge only and does not replace information provided by healthcare professionals. If you have any concerns of any skin growth, you should consult a medical professional urgently. Please also read our disclaimer.