Speckled lentiginous nevus: within the spectrum of congenital melanocytic nevi.

BACKGROUND Currently, there is disagreement as to whether speckled lentiginous nevi (nevi spili) are congenital or acquired pigmented lesions. Part of this controversy is related to the natural history of these lesions that often present at birth as hyperpigmented patches and then take several years to reach their more readily recognized spotted form. Arguments in favor of speckled lentiginous nevi as a subtype of congenital nevi include the following observations: multiple reports of lesions present at birth or noted soon thereafter; patterns of distribution reflecting embryonic development; hamartomatous behavior with various types of nevi (eg, junctional nevi, blue nevi, and Spitz nevi) presenting in the same lesion over time; and histologic features of congenital melanocytic nevi within the spots. Herein we present additional evidence for the congenital nature of speckled lentiginous nevi. OBSERVATIONS Ten patients are described with congenital pigmented lesions that had the clinical appearance of speckled lentiginous nevi in whole or in part. These lesions either evolved and acquired an appearance more suggestive of "classic" congenital nevi, or they existed as "hybrid" lesions with portions appearing as classic congenital nevi adjacent to or admixed with portions appearing as speckled lentiginous nevi. On histologic examination, biopsy specimens from the spots within these lesions showed features of congenital melanocytic nevi. CONCLUSIONS These 10 cases, along with the arguments outlined above, provide strong support for the hypothesis that speckled lentiginous nevi are a subtype of congenital melanocytic nevi.