Dermatology Online Journal

Homogeneous blue pattern: A rare presentation in an acral congenital melanocytic nevus
Francisco Manuel Almazán-Fernández, Maria-Antonia Fernández-Pugnaire, Jesús Hernández-Gil, Salvador Arias-Santiago, José Abad-Romero, Salvio Serrano-Ortega, Ramón Naranjo-Sintes
Dermatology Online Journal 16 (8): 10

Hospital Clínico San Cecilio

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Abstract

Acral melanocytic nevi are relatively frequent in the palmoplantar location. In congenital nevi various characteristic dermoscopic patterns have been described, such as reticular and globular patterns, brown pigmented areas, and areas with peripilar depigmentation. However, there are few reports on the dermoscopic pattern of acral congenital nevi. The homogeneous blue pattern is typical of blue nevus and is not typical of acral localization and metastasis of cutaneous melanoma. However, this pattern should be considered characteristic of acral congenital nevus.

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Introduction

Acral melanocytic nevi are relatively frequent in palmoplantar locations. It is important to establish that they are not acral melanoma. For this reason, dermoscopy is a helpful additional test. Dermoscopy is commonly used to distinguish acquired acral nevi and melanomas. However, the dermoscopy pattern of acral congenital nevi have not been clearly delineated.

Case report

Acral melanocytic nevi are relatively frequent in palmoplantar locations. It is important to establish that they are not acral melanoma. For this reason, dermoscopy is a helpful additional test. Dermoscopy is commonly used to distinguish acquired acral nevi and melanomas. However, the dermoscopy pattern of acral congenital nevi have not been clearly delineated.

Figure 1	Figure 2

A 30-year-old woman, with no personal or family history of interest, was referred to the Melanoma Unit of University Hospital San Cecilio of Granada because she had a pigmented lesion located on the right foot, present since birth. Clinical examination revealed a bluish plaque, 40 x 20 mm in diameter, with well-defined and regular borders (Figure 1). Dermoscopy showed a homogeneous blue pattern similar to that described in blue nevi and melanoma metastases (Figure 2). Excision was performed and the pathological diagnosis was intradermal melanocytic congenital nevus, because of the presence of melanocytes, without atypia, infiltrating the skin appendages. There was maturation in the deeper areas and the presence of nevus cells in “Indian file” between collagen fibers (Figure 3).

Congenital melanocytic nevi are present in 1 percent of newborns. They may be small, medium, or giant (>20cm) and the development of malignancy appears to be associated the lesion size (with a risk of between 5% and 40% for patients with giant nevus) [1]. Acral congenital nevi are less common than in other locations.

Acral nevi have well-defined dermoscopic patterns of which parallel furrow, latticelike structure, and fibrillar pattern are the most prevalent [2]. Other patterns described are the atypical and globular patterns and the homogeneous lattice, which is considered by some authors to be related to an involutional phase [3].

In congenital nevi various patterns such as reticular and globular patterns, brown pigment areas, and areas with peripilar depigmentation have been described. When there is a papillomatous surface, fissures and crypts and even comedo-like holes may be seen. Dark blue areas have been observed in relation to the deeper component of the tumor.

In non-acral locations, thehomogeneous blue pattern is typical of blue nevus and metastasic melanoma. Cellular blue nevus with plantar location has been described as having a parallel ridge pattern and may be a simulator of melanoma [4].

However, there are few reports describing the dermoscopic pattern of the acral congenital nevus. Zaudek et al. describe an acral congenital nevus presenting with a combination of parallel furrow, lattice, and fibrillar patterns [5]. Garrido-Ríos et al., in 2008, described a similar case to ours in a 46-year-old woman [6]. In this case, as in ours, the location of the nevus cells in the deep dermis produced this homogeneous blue pattern, similar to blue nevus.

We believe that this homogeneous blue pattern should be considered to be a characteristic of acral congenital nevus and although it is a benign pattern, we recommend close monitoring or removal of these congenital nevi.

In our case, given the size of the lesion, we preferred to excise the nevus; reconstruction by rotation flap produced an excellent functional outcome. This type of reconstruction of the sole should lead to optimal functional results, with protection of sensation and solid anchoring to deep tissue. Reconstruction by grafting is not a good option in areas of pressure. The ideal is to make a flap to cover areas of pressure. If necessary, the donor site may be grafted without pressure with walking [7].

References

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6. Garrido-Ríos AA, Carrera C, Puig S, Aguilera P, Salerni G, Malvehy J. Homogeneous blue pattern in an acral congenital melanocytic nevus. Dermatology. 2008; 217: 315-7. [PubMed]

7. Hong JP, Kim EK. Sole reconstruction using anterolateral thigh perforator free flaps. Plast Reconstr Surg. 2007;119(1):186-93. [PubMed]

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