Dermoscopic Features of Congenital Melanocytic Nevus and Becker Nevus in an Adult Male Population: An Analysis with a 10-Fold Magnification

Abstract

Background: Dermoscopic features of congenital melanocytic nevi (CMN) have been mostly assessed by high-resolution videodermoscopy. However, optical dermoscopy with the 10-fold magnification is largely available. In some instances, the differential diagnosis between large CMN and Becker nevus (BN) may be difficult. Objective: The aims of this work were: (1) to assess by dermoscopy with the 10-fold magnification the morphological features which have been previously suggested as useful for the identification of CMN in high-resolution videodermoscopy; (2) to search and point out the dermoscopic features of BN; (3) to explore dermoscopic differences between CMN and BN. Methods: The subjects were observed among about 23,000 consecutive young men assessed at the Draft Council’s Medical Unit of the Italian Navy in Taranto for compulsory recruitment and referred to the Department of Dermatology of the Italian Navy Hospital for dermatological examination. Lesions were examined by the same observer using a dermatoscope with a 10-fold magnification, and both the dermoscopic criteria stated by the international Consensus Net Meeting on Dermoscopy and dermoscopic features previously suggested as useful for the identification of CMN by videodermoscopy were recorded in a predisposed patient’s card. Results: There were 127 male subjects, median age 19 years, with 127 CMN, measuring ≧1.5 to ≤19.9 cm in 78% and ≧20 cm in 22% of cases, and 64 male subjects, median age 19 years, with 64 BN. In the sample of medium-sized and large CMN, dermoscopic features previously identified as characteristic of congenital lesions (i.e. target network, focal thickening of network lines, target globules, skin furrow hypopigmentation, focal hypopigmentation, hair follicles, perifollicular hypopigmentation, vessels and target vessels) were observed in sufficiently high rates. In the BN group, network, focal hypopigmentation, skin furrow hypopigmentation, hair follicles, perifollicular hypopigmentation and vessels were the main dermoscopic features. Focal thickening of network lines, globules, target globules, homogeneous diffuse pigmentation, hyperpigmented areas, blotches and target vessels were more frequently observed in CMN than in BN. Conclusions: (1) The same dermoscopic features observed in small and medium-sized CMN by videodermoscopy with high magnifications are also detectable in medium-sized and large CMN, employing the dermoscopy with the 10-fold magnification. (2) Network, focal, skin furrow and perifollicular hypopigmentation, hair follicles and vessels could be considered as peculiar dermoscopic features of BN. (3) Major differences in the frequency of dermoscopic characteristics were detected between CMN and BN, and dermoscopy seems to provide some diagnostic aid in differentiating CMN from BN in equivocal cases.

Age- and Site-Specific Variation in the Dermoscopic Patterns of Congenital Melanocytic Nevi

“…Many of these structures have been previously described as common features of CMN. [7][8][9]12,15 If the dermoscopic appearance of the lesion revealed that a single pattern was present in greater than one-third of the total area of the lesion, that lesion was classified as having 1 of the following 5 predominant dermoscopic patterns: reticular, globular, reticuloglobular, diffuse background pigment with or without remnant structures, or other. A reticular pattern was defined as a primarily reticular pattern, a globular pattern was defined as a primarily globular pattern, and a reticuloglobular pattern was defined as peripheral reticulation with central globules.…”

“…We note that this network has been previously described as a reticular network centered by a dot. [7][8][9] However, a variety of different structures, such as dots, globules, and vessels, may occupy the spaces of a reticular network ( Figure 5). Because the spaces of the network have a targetlike appearance in each case, strictly speaking, a network may be accurately described as a target network regardless of the exact type of structure present.…”

“…[4][5][6] The identification of distinct dermoscopic features of CMN may provide an important diagnostic tool for distinguishing between CMN and other pigmented lesions. Previous studies [7][8][9] indicate that CMN exhibit distinct dermoscopic features that may be helpful in distinguishing CMN from acquired melanocytic nevi and Becker nevi. There is also evidence that suggests that dermoscopy may be effective in detecting early malignant changes.…”

Literature Update on Melanocytic Nevi and Pigmented Lesions in the Pediatric Population

“…A recent retrospective study of 118 children in Italy with a diagnosed Becker nevus showed a nearly equal distribution among sexes (47 % male) in contrast to the common assumption of predominance in adolescent males [62]. Hypertrichosis also was present in only one-third of cases as compared to the presence of terminal hairs in the Becker nevi of 70 % of young Italian men [63]. The authors attribute this observation to the young age of the study patients, many of whom were preadolescent and thus had not experienced prominent hormone changes.…”

Update on Epidermal Nevi and Associated Syndromes

“…Skin furrow and perifollicular hypopigmentation also can be present. Hair follicles and vessels are apparent [57]. BN are not generally considered to have malignant potential.…”