Combination of Cultured Epidermal Autograft and Meshed Skin Graft Enables Full-thickness Excision of Giant Congenital Nevus.

Giant congenital melanocytic nevus (GCMN) is a skin condition characterized by an abnormally dark, noncancerous skin patch. Two main issues with GCMN are aesthetics and malignant transformation. Various methods of treatment are reported, but each method has its own disadvantages, such as risk of recurrence or restriction in the treatable area. We report three cases of GCMN treated with full-thickness excision and immediately covered with cultured epidermal autograft (CEA) combined with split-thickness skin graft (STSG). This is a single-center, single-arm, retrospective report of three cases. The nevus was excised at full skin thickness. Meshed STSG taken from scalp was grafted to the defect, and CEA was grafted over simultaneously. Two weeks later, CEA was applied again as a booster. The same procedures were performed until all nevi were excised. In all cases, nearly complete epithelialization was achieved at several weeks after operation. The reconstructed skin was elastic, and there was no persistent joint contracture. Vancouver Scar Scale score was 4-8. Mesh-like appearance was observed. A hypertrophic scar appeared in the area without meshed STSG. An intractable keloid was observed in one patient. No recurrence of the nevus was observed during the follow-up period. The donor site scar on the scalp was well hidden by the hair. Our method enables full-thickness resection and reconstruction of a wider area in a single operation while improving the take rate of CEA, with reasonable degree of scarring compared with conventional methods.

Functional and long-lived melanocytes from human pluripotent stem cells with transient ectopic expression of JMJD3.

BACKGROUND: Melanocytes are an essential part of the epidermis, and their regeneration has received much attention because propagation of human adult melanocytes in vitro is too slow for clinical use. Differentiation from human pluripotent stem cells to melanocytes has been reported, but the protocols to produce them require multiple and complex differentiation steps. METHOD: We differentiated human embryonic stem cells (hESCs) that transiently express JMJD3 to pigmented cells. We investigated whether the pigmented cells have melanocytic characteristics and functions by qRT-PCR, immunocytochemical analysis and flow cytometry. We also investigated their biocompatibility by injecting the cells into immunodeficient mice for clinical use. RESULT: We successfully differentiated and established a pure culture of melanocytes. The melanocytes maintained their growth rate for a long time, approximately 200 days, and were functional. They exhibited melanogenesis and transfer of melanin to peripheral keratinocytes. Moreover, melanocytes simulated the developmental processes from melanoblasts to melanocytes. The melanocytes had high engraftability and biocompatibility in the immunodeficient mice. CONCLUSION: The robust generation of functional and long-lived melanocytes are key to developing clinical applications for the treatment of pigmentary skin disorders.