Mohs Surgery |Skin Cancer | MedStar Health

Mohs micrographic surgery (“Mohs”) is a highly specialized microscopically guided form of surgery used in the treatment of skin. The surgeon removes the skin cancer layer-by-layer, examining each layer microscopically in the lab during the procedure day. If any cancer remains within a layer, your surgeon will be able to map the residual focus and then remove additional skin only where it’s necessary until no further cancer is seen. Unlike other treatment methods, Mohs surgery allows for complete peripheral and deep surgical margin evaluation, which offers patients the highest cure rate while minimizing the surgical defect.

While certain small tumors in low-risk areas may not qualify for Mohs surgery, this procedure is particularly appropriate in treating skin cancers on functionally and cosmetically sensitive regions on the head and neck, hands and feet, genitalia, as well as larger cancers, those with more aggressive behavior, and those that have recurred after prior treatments.

Mohs surgery is often used for common skin cancers, like basal cell carcinoma, squamous cell carcinoma, and some forms of melanoma, as well as rarer skin cancers such as atypical fibroxanthoma, dermatofibrosarcoma protuberans and others.

Frequently asked questions

  • Should I get Mohs surgery?

    Mohs surgery may not be appropriate if your cancer is small and on less cosmetically and functionally sensitive regions like the back. If your cancer is on a cosmetically or functionally sensitive region such as the head and neck, hands and feet, genitalia, or in close proximity to bone (over the shins, for example), you may qualify based on tumor location. Other indications for Mohs surgery include larger size, aggressive histology, poorly defined clinical margins, recurrence, and if you are immunosuppressed. We would recommend discussing the appropriateness of this procedure with your primary dermatologist or with our team.

  • What can I expect on the day of surgery?

    Mohs surgery is an outpatient procedure that is done under local anesthesia, similar to what you received when the lesion was initially biopsied. There is no need to discontinue eating and drinking prior to the surgery. Due to the nature of this being a microscopically-guided surgery we do recommend that you block the entire day and avoid any other commitments as the length of the procedure is guided by the size and complexity of the tumor. Since skin cancers can demonstrate subclinical spread (invasion not visible on the surface of the skin) so the number of layers or stages can be difficult to predict. We recommend bringing a good book/magazine, your phone, and anything else you may need to stay comfortable and engaged during your procedure day.
  • How will my Mohs site be repaired?

    Mohs surgery defects can be repaired in a number of ways, including secondary intention healing (allowing the body to heal itself), closing the defect linearly, using a skin flap, or using a skin graft. The repair often depends on the location of the defect as well as the size and depth of the final wound. Your Mohs surgeon is trained in surgical reconstructive techniques and will be able to best counsel you once the final defect has been established. In some circumstances we may work with other surgical colleagues in the repair of complex defects.

  • Do I need any imaging tests?

    Most patients will not require any additional imaging tests prior to Mohs surgery, however it is important to discuss your individual case with your provider.

  • Do I need any other treatments after Mohs surgery?

    The majority of patients will not require any additional treatment such as radiation or chemotherapy after Mohs surgery, but please discuss your individual case with your provider. We do recommend establishing routine skin exams with your dermatologist as the risk of developing subsequent skin cancers increases if you have already had a skin cancer.