Recent changes in speckled pigmented lesion

Abstract

A 54-year-old Caucasian male (phototype III) was referred via the skin cancer screening pathway with a skin lesion present since infancy. He reported a 1-year history of change with no associated symptoms.

He did not report a prior family history of skin malignancy. He had a significant history of sun exposure as he worked in the Royal Navy in the past. He denied any associated symptoms.

On examination, there was a background 4.5 × 5 cm pigmented speckled lesion with a nodular component. Dermoscopy showed a large background light brown patch with a few scattered darker pigmented macular lesions with a reticular pattern. Additionally, noted a nodular component with darker coalescing irregular reticular pattern with associated structureless central zone (Figure 1). In view of the suspicious clinical and dermoscopic features, the lesion, both macular and nodular component was excised with a 2 mm margin (Figure 2).

Nevus spilus is a rare type of congenital lesion initially described in 1842 by Burkley.¹ It consists of a background patch of hyperpigmentation with darker speckled macules or papules. It is uncommon, found in 0.2%−2.3% of the population.²

In our case, we observed (Figure 1a,b) on dermoscopy two distinct features: an area of change within a pre-existing lesion with background pale brown patch and speckled pigmented macules and an area of recent change with and a nodular component with milky red areas and polymorphous atypical vascular structures with a pigmented patch showing peripheral dots and globules and brown structureless zones. These changes were highly suggestive of a malignant transformation.

Previously, NS was considered an innocuous pigmented lesion. However, the first case of a melanoma arising within a NS was reported in 1957 by Perkinson.³ There have been approximately 30 cases published of this type of clinical presentation. Within the literature, most cases of malignant transformation were noted in Caucasian or Afro-Caribbean patients, with a slight female preponderance. Common sites of presentation were noted on the limbs (36%) and trunk (64%) and the mean age of diagnosis was 49 years.^{4, 5}

NS generally presents as three sizes: small (<1.5 cm), medium (1.5–19.9 cm) and large (>20 cm), with rarer presentations being segmented and zosteriform.⁴

There is no clear consensus, as this presentation is not common, but it is thought that the risk of malignant transformation is around 0.13%–0.2%.⁶

However, once a melanoma arises, there is no clear difference in terms of management and prognosis when compared to melanomas which arise in other clinical circumstances. The prevalent practice of self-monitoring, photographic documentation, and long-term follow-up with dermoscopy is favoured.⁷ Additionally, the biopsy of suspicious areas within NS aids in the early detection of malignant transformation. There is no evidence in the literature to encourage prophylactic excision of lesions in the absence of confirmed dysplasia or malignancy. When dysplasia or malignancy is biopsy confirmed, if the size of the lesions allows, complete excision should be performed to investigate the potential for other areas of dysplasia or multifocal melanomas. In our case, the size of the lesion allowed for complete excision and histological evaluation of both background lesion and area of malignant transformation.

In the eventuality of large, segmental, or zosteriform lesions there is no consensus regarding complete excision and the size makes such interventions difficult. There have been case reports of complete excision of large lesions with good results with noted synchronous melanomas detected within the background NS.^{5, 8} However, other cases of segmental NS have opted for removal of areas of synchronous malignant transformation with background larger lesion being closely monitored.⁹

Irina Nocivin led the conception and draft of article with review of data. Rakesh Anand, Parastoo Babakinejad, Andrew Giles and Khushboo Sinha revised critically and approved version to be published.

The authors declare no conflict of interest.

The patient in this manuscript has given written informed consent for participation in the study and the use of their deidentified, anonymized, aggregated data and their case details (including photographs) for publication. Ethical Approval: not applicable.