Autologous Engineered Skin for Coverage after Giant Congenital Melanocytic Nevi Resection

Background

Giant Congenital Melanocytic Nevus (GCMN) is a proliferation of melanocytic cells present at time of birth with an expected diameter >20cm by the time of adulthood (1). GCMN has been associated with malignant melanoma, rhabdomyosarcomas and other tumors (1). Nevertheless, its resection in order to reduce the risk of malignancy is still controversial (2). Surgical excision is in most cases performed for aesthetic purposes, therefore, the need for techniques that  minimize surgical sequelae (1).

Coverage of the wound bed can be challenging, specially with nevi that involve more than 20%of total body surface area(TBSA). Serial extirpation after tissue expansion is the gold standard treatment for nevi located in the trunk, scalp and face. However, for lesions located in the buttocks or limbs skin grafts are the elective treatment, involving important aesthetic sequelae at donor site (3).

We present our long-term results with autologous engineered skin (AES) for coverage after  GCMN resection.

Methods

We performed a retrospective review of the medical records of a series of 5 pediatric patients suffering from Giant Congenital Melanocytic Nevus, operated in our department. Nevus resection was performed in one or more surgical procedures depending on nevus extension. A maximum of 15%TBSA was removed on each procedure and the defect was then covered with artificial dermal matrix. A skin biopsy of an unffected area was obtained from the patient and sent for culture to the Tissue Engineering Unit. After 3 weeks, which allowed for dermal matrix neovascularization and for keratinocytes expansion; AES was grafted over a well vascularized homogeneous wound bed.

Results

The average take percentage per grafting procedure was 46%SCT (15 – 95%). the major cause for graft loss was wound bed infection in early stages.  Average follow-up period was 11 years with a range of 2 – 14 years. Patient’s degree of satisfaction was evaluated with EQ-5D-Y health questionnaire, showing a health status evaluated between 95-100%. Results were evaluated with Modified Vancouver  Scar Scale (MVSS) and  Patient Observer Scar Assesment (POSAS). MVSS showed a total score of 6,25, being 14 the worst result. POSAS global evaluation was a 4,25, being 1 equal to normal skin, and 10 very different to normal skin.

Conclusions

GCMN management needs to be individualized. We can conclude that AES is a good surgical resource for coverage of defects after GCMN resection when tissue expansión might not be an option, avoiding or limiting donor sites and acting as a stable coverage with growth potential over time.

References:

1. Arad E, Zuker RM. The shifting paradigm in the management of giant congenital melanocytic nevi: review and clinical applications. Plast Reconstr Surg. 2014; 133: 367-76.
2. Bauer BS, Vicari FA. An approach to excision of congenital giant pigmented nevi in infancy and early childhood. Plast Reconstr Surg. 1988; 82: 1012-21.
3. Gosain AK1, Santoro TD, Larson DL, Gingrass RP. Giant congenital nevi: a 20-year experience and an algorithm for their management. Plast Reconstr Surg. 2001 Sep 1;108(3):622-36.