Congenital melanocytic nevi and nevus spilus have a tendency to follow the lines of Blaschko: an examination of 200 cases

Nevus Spilus With Dermatoheliosis: A Histologic Mimicker of Melanoma in Situ at Melanoma Excision Margins

ABSTRACT

Nevus spilus, or speckled lentiginous nevus, is a relatively common lesion that presents at birth or in early childhood. It consists of a background tan patch, which appears similar to a café au lait macule or lentigo simplex on histology, studded with various types of nevi. Rarely, these nevi can undergo malignant transformation to melanoma. When melanoma develops within a heavily photodamaged nevus spilus, evaluating excision margins may be challenging because the combined histologic features of nevus spilus and severe dermatoheliosis can mimic melanoma in situ. We report a case of an elderly man with extensive sun damage who developed malignant melanoma within an occult nevus spilus, resulting in multiple excisions with false-positive margins.

Segmental Pigmentation Disorder: Clinical Manifestations and Epidemiological Features in 144 patients, a Retrospective Case-control Study

Segmental pigmentation disorder (SPD) is characterized by hypo- or hyper-pigmented patches segmentally distributed, present in infancy, more prominently in darker-skinned children. The aim of this study was to define the demographic and clinical characteristics of SPD in a large series of patients. This was a retrospective case-control study at 2 paediatric dermatology centres in Israel. Data were collected through a telephone questionnaire and medical records. The study group consisted of 144 individuals with SPD and 144 individuals visiting the same institutions matched for age and sex. Median age of onset of SPD was near birth; 51% of patients were Sephardic Jews, and patients were followed up for a median period of 27 years. The patches were located on the torso (43%), mostly hypopigmented (52%), and remained of the same intensity and size in 55% and 41% of cases, accordingly. No differences in extracutaneous morbidities were found between SPD and control patients. This study delineates the demographic and clinical characteristics of SPD, confirms that cutaneous findings in SPD are more prominent in darker skin, tends not to expand in size or accentuate throughout the years, nor to be associated with extracutaneous morbidities.

Epidermal, sebaceous, and melanocytic nevoid proliferations are spectrums of mosaic RASopathies

Growing evidence demonstrates that various nevoid proliferations such as keratinocytic epidermal nevi and nevus sebaceous result from somatic mosaicism. Many of the mutations identified have been within the RAF/RAS/MAPK pathway, hence supporting the previously introduced term "mosaic RASopathy" for these nevi. In this issue, Kinsler et al. were among the first to characterize certain pigmented melanocytic nevi that may also fit this paradigm. To better frame these findings, we provide a summary of the analogous genotypic profiles for epidermal and melanocytic nevi from recent studies.

Nevus Spilus and Melanoma: Case Report and Review of the Literature

Background:

Nevus spilus is characterized by a pigmented patch with scattered flat or maculopapular speckles. Nevus spilus was first described by Burkley in 1842. Since then, this lesion has been widely debated in the literature, particularly for the possible occurrence of melanoma within the lesion.

Objective:

We describe the case of a 65-year-old female presenting with a nodular achromic melanoma that occurred within a nevus spilus on the left thigh.

Conclusion:

Our observation is consistent with the idea that this entity in some circumstances may have the ability to evolve into a malignant melanoma.