CHICAGO A treatment plan for infants and children with large and giant nevi must satisfy concerns about malignancy while optimizing aesthetic and functional outcomes for the patient, Dr. Bruce Bauer said at the annual meeting of the Society for Pediatric Dermatology.
"Conducting a critical assessment of a large or giant nevus in a child and choosing the appropriate procedures as early as possible will reduce the total number of surgeries and the need for complex surgery later on to deal with potential complications caused by scarring," noted Dr. Bauer, a pediatric plastic surgeon and chief of plastic surgery at Children's Memorial Hospital, Chicago, who specializes in the treatment of large and giant congenital nevi.
Each child and each tissue heal differently, and some surgeries are easier and more effective at earlier ages than later, he added.
Although various classifications for nevi exist in the medical literature, a nevus larger than 20 cm in a child is usually considered a giant nevus, and a nevus that is 1120 cm is considered large. In general, patients with large or giant nevi are at the greatest risk for malignant change, but size doesn't guarantee malignancy. The overall incidence of cutaneous or extracutaneous melanoma in patients with large or giant nevi is between 4.5% and 10%, said Dr. Bauer, and controversies persist about the medical necessity of plastic surgery to manage the nevi.
"The exact risk of malignant change in congenital melanocytic nevi may never be determined," Dr. Bauer acknowledged. "The managing physician or surgeon must develop a treatment philosophy based on an understanding of pertinent studies."
The primary rationales for excision of large or giant nevi are a concern for malignancy and a desire for an improved appearance. Some patients and physicians may decide that the risk of malignancy is too small to warrant the potentially extensive scarring or unsightly skin grafts needed to excise a large or giant nevus. But for those who make the decision in favor of excision, the sooner the better, Dr. Bauer said.
If the excision is performed in infancy or early childhood, the tissue is more flexible and heals more smoothly and rapidly. The psychological benefits and generally good patient tolerance also tip the scales in favor of early excision.
Tissue expansionin which skin adjacent to the nevus is stretched, with both stretch and new cell growth occurringprovides the added tissue needed to cover the area from which the nevus has been excised, and is now one of the most powerful tools available in the treatment of these extensive lesions. The ability to expand tissue of similar skin characteristics to the involved area allows expansion of hair-bearing scalp to replace a scalp nevus, and non-hair-bearing skin to replace nevi in all other areas.
Dr. Bauer shared some elements of his surgical approach to large and giant congenital nevi the following areas of the body:
▸ Scalp/forehead. Tissue expansion is the preferred method for treatment of large and giant nevi of the scalp and forehead, and has become the standard of care. Expansion may begin when the patient is as young as 6 months of age without long-term effects on the growing skull. In addition, the use of transposition flaps yields a more natural hairline reconstruction.
Good flap planning can reduce the need for repeated tissue expansion procedures, Dr. Bauer noted. Combined expansion of scalp and forehead for nevi that cover both areas will also reduce the number of surgical procedures needed to excise the nevus and reconstruct the defect. In rare cases in which minimal normal forehead skin is available, free tissue transfer can be considered, with expansion used at the distant donor sites to allow harvest of a large, microvascular free flap, with primary closure of the donor site, he explained.
▸ Midface/periorbital region. Tissue expansion can be used for large and giant nevi on the forehead, neck, and cheek, and large expanded full-thickness skin grafts may provide color-compatible coverage for the periorbital and nasal area in a single skin unit.
"As you get to the midface, you need to avoid distortion of the lateral canthus and the downward pull of the lower eyelid," Dr. Bauer noted. "Use of direct upward advancement of either expanded or nonexpanded flaps from the lower cheek and submental area may increase the risk of these problems," he added. Lateral movement with rotation or transposition of flaps reduces this risk.
With thoughtful flap planning, one can place scars at the borders of the natural aesthetic units of the face and minimize their visibility. With adequate time for tissue healing and changes in the reconstructed tissues with the child's growth, one can achieve a natural appearance and minimize the need for additional complex reconstruction later in life.