SAN DIEGO Certain areas of the body are more challenging than others when it comes to Mohs surgery: the nose, ears, and eyelids, as well as urology cases and orthopedic cases on the hands and feet.
These are the places where surgeons, especially beginners, are more likely to get into trouble and where tumors tend to be more aggressive. "Anywhere the skin is closer to bone, the tumor is more likely to spread in an unpredictable manner," Dr. Roger I. Ceilley said at a meeting sponsored by the American Society of Mohs Surgery.
To tackle the tough Mohs surgery cases, physicians need a lot of experience and time spent working with other surgeons, said Dr. Ceilley, a Mohs surgeon and dermatologist in practice in Iowa.
Cancers in the nose, which tend to be deeply invasive and can be hard to detect, have a higher recurrence rate, compared with cancers in other areas, he said. Particularly tricky areas around the nose are the columella, nasolabial groove, supra tip area, and lateral nasal dorsum. Before performing Mohs surgery on tumors of the nose, physicians should conduct a scouting biopsy to determine the extent of the lesions and to remove all scar tissue. Be aware that a tumor of the nose could be the tip of a larger iceberg, and prepare in advance for possible collaboration with a head and neck surgeon, he advised.
Treating cancer of the ear with Mohs surgery may involve working around the parotid gland, as well as around many nerves. Skin cancers of the ear have a 16%47% recurrence rate, which is higher than that of skin cancers elsewhere. For these cases, it is important to know the anatomy of the ear, especially the nerve distribution and nerve supply. The anatomy of the ear is complex, and the surgeon must anticipate that the tumor may be much larger than it appears clinically. That said, the back of the ear is a good place to perfect one's skin flap technique, he noted.
Most surgeons can handle procedures on the lower eyelid, but upper eyelid tumors require an immediate repair and the use of an eye shield to protect the cornea and prevent corneal dryness.
"I wouldn't tackle tumors on the upper eyelid if you think it will be full thickness because you need to do an immediate repair, and you have to keep a corneal shield in place on the eye to prevent drying of the cornea. A little carbon char can cause a corneal abrasion. Make sure you use plenty of ointment before and after surgery," he said.
If you plan to perform Mohs surgery in the genital area, arrange ahead of time to work with a urologist. Dr. Ceilley discussed a patient with penile cancer who was slated for a penectomy, but was not enthusiastic about that idea and wanted to try Mohs surgery. (See photo.)
The surgery involved use of a catheter, and the tumor had to be followed into the urethra. After excision of the tumor, the wound was not sutured, but allowed to heal by second intention. The patient has had no recurrence of cancer to date. "He has to watch where he points, but he has a functional penis," Dr. Ceilley said.
Mohs surgery also may be used to successfully treat cancer, especially squamous cell carcinoma, on the extremities. In the case of a verrucous squamous cell carcinoma, "the tumor went nearly through to the other side of the foot," he said. Dr. Ceilley collaborated with an orthopedic surgeon, who amputated several toes. The surgeon used the skin from those toes to create skin flaps and give the patient a functional foot. (See photo.)
Expect the unexpected in Mohs cases. "You can find tumors that look like a basal cell carcinoma and turn out to be a Merkel cell carcinoma," he said.
Microcystic adnexal carcinoma, a rare but deeply infiltrating tumor, can be treated by an experienced Mohs surgeon. Characteristic features of microcystic adnexal carcinoma include a bland appearance, ambiguous histopathology with bizarrely shaped parent cells, and aggressive clinical behavior. Permanent horizontal sections are highly useful in these cases, Dr. Ceilley said.
Lentigo maligna also can be treated with Mohs surgery, and surgeons can use imiquimod (Aldara) to decrease the size of the area prior to surgery and to facilitate healing after surgery.
Finally, for challenging or complex cases, Dr. Ceilley recommends getting permanent paraffin-embedded sections, in addition to the multiple frozen sections that may be needed.
A squamous cell carcinoma of the penis was successfully excised.
