Giant nevus sebaceus: Definition, surgical techniques, and rationale for treatment

Background: A reduction in the reported incidence of malignant degeneration within nevus sebaceus has led many physicians to recommend serial clinical evaluation and biopsy of suspicious areas rather than prophylactic surgical excision. Unfortunately, no well-defined inclusion criteria, including lesion size and location, have been described for the management of nevus sebaceus. Methods: To assess whether the incidence or timing of malignant degeneration contraindicates surgical excision, the authors performed a PubMed literature search for any studies, excluding case reports, related to malignant change within nevus sebaceus since 1990. They then defined giant nevus sebaceus to consist of lesions greater than 20 cm or greater than 1 percent of the total body surface area and retrospectively examined their experience and outcomes treating giant nevus sebaceus. Results: Data were pooled from six large retrospective institutional studies (2520 patients). The cumulative incidence of benign and malignant tumors was 6.1 and 0.5 percent, respectively. Of the authors' 195 patients with giant congenital nevi, only six (3.0 percent) met the definition of giant nevus sebaceus. All patients required tissue expansion for reconstruction, and two patients required concomitant skin grafting. Two complications required operative intervention. Conclusions: Early malignant degeneration within nevus sebaceus is rare. Management, however, must account for complex monitoring, particularly for lesions within the scalp, associated alopecia, involvement of multiple facial aesthetic subunits, and postpubertal transformation affecting both appearance and monitoring of the lesions. The latter considerations, rather than the reported incidence of malignant transformation, should form the bases for surgical intervention in giant nevus sebaceus. Clinical Question/Level of Evidence: Therapeutic, V.