Nevus Spilus: A Review of the Literature

Abstract

Since Burkley first adopted the term Nevus spilus (NS) in 1842, then, many terms have been used as synonyms in the literature to indicate this lesion; speckled nevus: nevus on nevus, naevus sur naevus, spotty nevus, speckled lentiginous nevus, speckled zostriform lentiginous nevus, speckled nevus spilus, cafè au lait spot and partial unilateral lentiginosis. NS refers to a more or less circular shaped lesion, a tan to light brown patch of various sizes and sites, either congenital or acquired and characterized by multiple small darker brown macules superimposed, which can be flat or raised and irregular in nature (Figure 1). The histological patterns of the colored base are those of a simple freckle (macula) or cafè-au-lait patch, whilst the spotted lesions are usually made up of junctional, compound, or intradermal nevi. As a rule, NS is not considered a precursor of melanoma, but more than one case has been reported of melanoma arising in NS [1-31]. We will analyze the clinical characteristics and the general evolution of NS and the risk factors of turning malignant. Abstract Nevus spilus (NS) is usually the term given to a pigmented skin lesion, either congenital or acquired, consisting of a large light tan patch, containing macules or papules. Usually, these superimposed lesions are numerous, small circumscribed, dark brown in color, flat or slightly raised. Nevus spilus can be seen anywhere on the body surface, but the most common location is on the chest and upper limbs. NS was first described by Burkley in 1842 as evenly pigmented patches and Ito and Hamado in 1952 were the first to apply the term NS to speckled lesions. For a long time, NS was believed to be a benign lesion. However, more than one case of melanoma arising in NS has been published. As a rule, NS is not considered a precursor of melanoma, but to this day, despite the wide range of publications, it is still necessary to clarify the relationship between NS and melanoma, in terms of the risk factors of turning malignant. We will describe the clinical features, the evolution and the management of NS, in view also of the recent genetic findings. (a) (b) Figure 1: The classic aspect of nevus spilus (brown patch and darker macules within).