Dermoscopy for the Pediatric Dermatologist Part III: Dermoscopy of Melanocytic Lesions

Abstract

Melanocytic nevi encompass a variety of lesions, including blue, Spitz, congenital, and acquired nevi. These nevi can occasionally manifest clinical morphologies resembling melanoma, and the presence of such nevi in children can elicit anxiety in patients, parents, and clinicians. Dermoscopy has been shown to increase the diagnostic accuracy for melanoma and to help differentiate melanoma from nevi, ultimately aiding in the decision-making process as to whether to perform a biopsy. Dermoscopy is the perfect instrument to use during the evaluation of pigmented skin lesions in children because it is painless and provides important information for the clinician that can assist in formulating appropriate management decisions. This review highlights the most common benign dermoscopic patterns encountered in nevi and discuss the 10 most common dermoscopic structures seen in melanomas. Lesions manifesting a benign dermoscopic pattern and lacking any melanoma-specific structures do not need to be excised and can safely be monitored. In contrast, melanomas will invariably deviate from the benign nevus patterns and will usually manifest at least 1 of the 10 melanoma-specific structures: atypical network, negative network, streaks, crystalline structures, atypical dots and globules, irregular blotch, blue-white veil, regression structures, peripheral brown structureless areas, and atypical vessels. It is important to be cognizant of the fact that melanomas in childhood usually do not manifest the clinical ABCD features. Instead, they are often symmetric, amelanotic, nodular lesions. Although the clinical appearance may not be alarming, with dermoscopy they will invariably manifest at least one melanoma-specific structure, the most common being atypical vascular structures and crystalline structures.

Dermoscopy pathology correlation in melanoma

“…Recognition of a flat amelanotic melanoma is very difficult because of the absence of specific dermoscopic criteria coupled with the paucity of the available anamnestic data about the tumor growth. However, according to Argenziano et al ., dermoscopy of amelanotic flat melanoma may be characterized by crystalline structures, namely: fine, white, shine lines, usually arranged in an orthogonal manner, visible only on polarized light, and corresponding histologically to remodeled or new dermal collagen . The crystalline structures or chrysalis structures, behind the invasive melanoma, could be observed also in other skin tumors, such as basal cell carcinoma, dermatofibromas, scars and, rarely, even in (desmoplastic) nevi …”

Dermoscopic patterns of melanocytic nevi in children and adolescents: a cross-sectional study

“…3 However, the globular pattern on dermoscopy (which correlates with compound or dermal nevi, and is expected to appear later) has shown, in other studies, to be predominant in children. 1,13-16 Therefore, the globular pattern can also be associated with actively growing nevi, and the patterns can change according to age.…”

“…3 This technique is ideal for the evaluation of pigmented skin lesions in children, as it is painless and provides important information that can assist physicians in formulating appropriate management decisions. 1 Nevertheless, studies of dermoscopic nevi patterns in children, which are essential for the understanding of nevogenesis, are still scarce in medical literature. 3 …”

Congenital Melanocytic Nevi

“…CMN on the head, neck, and trunk of children frequently exhibit a globular pattern, whereas those arising on the extremities (particularly the lower limb) often display a reticular pattern [ 50 ].…”