• Mohs micrographic surgery is a microscopically controlled method of removing skin cancers that allows for controlled excision and maximum preservation of normal tissue.

• Most reliable method in determining adequate margins

• Cure rate between 98% and 99% for basal cell carcinomas

• Preserves the maximum amount of normal tissue around the cancer

• Time-consuming

• Expensive

• May require extensive reconstruction of surgical wounds

Mohs surgery is mostly suited for:

• Recurrent basal and squamous cell carcinomas, particularly those on the face

• Excessively large (>2 cm) or invasive carcinomas

• Carcinomas within an orifice (e.g., ear canals or nostrils)

• Carcinomas in locations where preservation of normal tissue is extremely important (e.g., tip of the nose, ala nasi, eyelids, ears, lips, glans penis)

• Carcinomas in locations known to have a high rate of recurrence (e.g., ala nasi, nasal labial folds, medial canthi, pinnae of the ears, postaurical sulcus)

• Morpheaform or sclerotic (desmoplastic) basal cell carcinoma

• Lesions of the finger or penis

• Excise the tissue in a circular pie-shaped fashion; then systematically map it and examine it by means of frozen sections (Fig. 35.25A-D).

• While the patient waits in the examining room, submit the tissue to a histotechnician for the surgeon to review.

• Repeat excisions in the areas proven to be cancerous until a complete cancer-free plane is reached. Several stages may be necessary.

• Surgical wounds may be left to heal by secondary intention or corrected by plastic reconstructive procedures.

• Infections after simple skin surgery are unusual.

• Administration of systemic antibiotics is generally unnecessary.

• Meticulous hemostasis during surgery is essential.

• Small amounts of necrosis normally occur in wound healing.

• Hemostasis induced by electrosurgery, suture ligature, or cautery always produces tissue necrosis.

• Wound healing is delayed when necrosis is extensive.

• Hemostasis can be achieved with a pressure dressing, which is applied for 24 hours.

• When wounds are closed with a considerable amount of tension or if the patient has been taking steroids, the wound should be closed with sutures that are nonabsorbable and buried (nylon or polypropylene) or have prolonged tensile strength (PDS, Dexon, or Vicryl). Under the former conditions, skin sutures may be left in place for longer periods of time.

• External splinting using tape provides additional support until the tensile strength of the wound increases after suture removal.

• Exercise that stretches the skin should be avoided to minimize spreading of the scar.

• For small ellipses, dry, sterile gauze covered with paper tape may be all that is necessary.

• An occlusive dressing or pressure dressing should be applied, if necessary, to prevent postoperative bleeding.

• After 24 hours, the patient can remove the dressing and compress the wound with tap water or hydrogen peroxide. The hydrogen peroxide mechanically softens the wound and removes any debris.

• A topical antibiotic such as bacitracin or plain petroleum jelly (Vaseline) is applied to the surface of the wound before applying a clean, occlusive dressing.

• Patients repeat this procedure daily at home until the wound is covered with fresh epidermis.

• Patients are advised to return for follow-up if there is any pain, swelling, tenderness, purulent drainage, discharge, or bleeding of the wound.

• Postoperative pain usually is negligible, and patients are advised to call the surgeon should any pain occur.