The dermoscopic classification of atypical melanocytic naevi (Clark naevi) is useful to discriminate benign from malignant melanocytic lesions

BACKGROUND: The dermoscopic classification is a useful tool for handling patients with atypical naevi (Clark naevi). OBJECTIVES: To investigate if the dermoscopic classification of atypical naevi is of any value to discriminate benign from malignant melanocytic lesions. METHODS: Consecutive patients (n = 205) were included with 254 suspicious melanocytic lesions, confirmed by histopathology at the Pigmented Lesions Clinic of the Department of Dermatology, University Medical Center, University of Tuebingen, Germany. In this retrospective study, dermoscopic images of benign and malignant melanocytic lesions were classified according to the dermoscopic classification of atypical naevi (reticular, globular, homogeneous or combinations of two of these) and pigmentation (uniform, central hyper- or hypopigmentation, eccentric peripheral hyper- or hypopigmentation, or multifocal hyper- or hypopigmentation). The three-structure type (reticular, globular and homogeneous) was additionally defined. RESULTS: Reticular, homogeneous and reticular-homogeneous types were significantly more frequent in naevi than in melanomas, whereas the three-structure type was significantly more frequent in melanomas (P < 0.001). A sensitivity of 86.7%, specificity of 87.7% and diagnostic accuracy of 87.4% was obtained. Uniformly pigmented and centrally hyperpigmented types were significantly more frequent in naevi than in melanomas, whereas eccentric peripheral hyperpigmented and multifocal hyper- or hypopigmented types were significantly more frequent in melanomas (P < 0.001). CONCLUSIONS: The dermoscopic classification of atypical naevi (Clark naevi) is useful to discriminate benign from malignant melanocytic lesions. The three-structure type and eccentric peripheral hyperpigmentation were significantly more frequently found in malignant than in benign melanocytic lesions. The knowledge of these two dermoscopic types should be helpful for the management of patients presenting with multiple melanocytic lesions.     

Klinische Wertigkeit einer dermatoskopischen Klassifikation von Clark‐Nävi

Background and objectives: The aim of this study was to evaluate the practical value of the dermatoscopic classification of Clark nevi Patients and methods: Dermatoscopic images of 268 lesions clinically and dermatoscopically diagnosed as Clark nevi were presented to 2 dermatologists without knowledge of the histological diagnosis. The dermatologists evaluated the lesions according to a simplified version of the classification scheme for Clark nevi proposed by Hofmann‐Wellenhof and differentiated between 12 different types of Clark nevi. Results: The most common type of Clark nevus was the reticular‐homogenous type (n = 64, 23,9 %), followed by the globular‐homogeneous type (n = 32, 12 %) and by the homogenous type (n = 30, 11,2 %). The overall inter‐rater agreement between the examiners was moderate to good (kappa = 0,58). The highest level of agreement was found for the peripheral hyperpigmented type (kappa = 0,83). Histologically, 17 lesions (6,3 %) were diagnosed as melanomas. The frequency of melanoma was highest among the peripheral‐hyperpigmented type for one observer and among the homogenous type for the other observer. No melanoma was found among the globular, reticular‐globular, and the central‐hyperpigmented types. Conclusions: A dermatoscopic classification of Clark nevi is practically feasible and allows – to some extent – a risk stratification of Clark nevi, which could be useful for clinical management.     

Age- and site-specific variation in the dermoscopic patterns of congenital melanocytic nevi: an aid to accurate classification and assessment of melanocytic nevi

OBJECTIVES: To describe the dermoscopic features of congenital melanocytic nevi (CMN) and assess whether predominant dermoscopic patterns present in CMN are related to an individual's age (<12 years vs >or=12 years), sex, or lesional site (head, neck, and trunk vs extremities). DESIGN: Nonrandomized observational study. PATIENTS: A total of 77 consecutive patients, each with 1 CMN (n = 77 lesions), from an outpatient dermatology clinic. A diagnosis of CMN was established by (1) documentation of a melanocytic nevus during the first year of life or (2) by clinical examination and either clinical history or biopsy findings. MAIN OUTCOME MEASURES: Images of CMN were evaluated for specific dermoscopic structures and patterns. The distribution of patterns was assessed by age, sex, and lesional site. RESULTS: Most of the 77 lesions exhibited 1 of the following predominant dermoscopic patterns: reticular (18 lesions [23%]), globular (14 [18%]), or reticuloglobular (12 [16%]). Globular CMN were present in 5 of the 19 individuals who were younger than 12 years (26%) but in only 9 of the 58 individuals 12 years or older (16%). Reticular CMN were seen exclusively in the individuals who were 12 years or older. Congenital melanocytic nevi exhibiting no predominant pattern were more commonly present in the individuals younger than 12 years. Globular CMN were present in 11 head, neck, and trunk lesions (30%) compared with 3 extremity lesions (8%). Conversely, reticular CMN were present in 16 extremity lesions (40%) compared with 2 head, neck, and trunk lesions (5%). The predominant dermoscopic pattern did not vary based on sex. The most commonly observed dermoscopic structures were globules (in 64 lesions [83%]), hypertrichosis (in 61 [79%]), and reticular networks (in 55 [71%]). CONCLUSIONS: Our results suggest that the predominant dermoscopic patterns of CMN vary according to age and lesional site. These differences may inform future studies on the pathogenesis of CMN.     

Dermoscopy patterns of halo nevi

BACKGROUND: Halo nevi (HN) are benign melanocytic nevi surrounded by a depigmented area (halo). This study aims to evaluate the dermoscopic features of HN and their changes during digital dermoscopic follow-up and to investigate the frequency of the halo phenomenon in a series of melanomas. OBSERVATIONS: In a retrospective study, digital dermoscopic images of HN from patients who attended the Pigmented Skin Lesions Clinic of the Department of Dermatology, Medical University of Graz, between October 1, 1997, and March 31, 2004, were reviewed and classified by dermoscopic morphologic criteria. For HN that were followed up with digital dermoscopy, the percentages of changes in the size of the nevus and halo components were calculated. In addition, digital dermoscopic images of histopathologically confirmed melanomas obtained from the same database were reviewed for the presence of an encircling halolike depigmentation. We classified 138 HN in 87 patients (mean age, 22.4 years). The most common dermoscopic structures were the globular and/or homogeneous patterns in more than 80% of HN. Follow-up of 33 HN revealed considerable size reduction of the nevus component, but this was not associated with significant structural changes. Of a total of 475 melanomas, only 2 revealed an encircling halo, but both displayed clear-cut melanoma-specific patterns according to dermoscopy. CONCLUSIONS: Halo nevi exhibit the characteristic dermoscopic features of benign melanocytic nevi, represented by globular and/or homogeneous patterns that are typically observed in children and young adults. Halo nevi reveal considerable changes of area over time during digital dermoscopic follow-up, albeit their structural patterns remain unchanged. For this reason and because melanoma with halolike depigmentation, despite being rare, additionally exhibits melanoma-specific dermoscopic criteria, the role of digital dermoscopic follow-up in the diagnosis of HN is insignificant.     

Natural History of Atypical and Equivocal Melanocytic Lesions in Children: An Observational Study of 19 Cases

Digital dermoscopy follow‐up helps to identify patterns of change typical of common atypical nevi and early melanoma and improves the follow‐up of patients with atypical nevi. We report the morphologic changes observed over time in 19 atypical or equivocal acquired melanocytic nevi that underwent dermoscopic follow‐up. Two observers retrospectively examined digitalized dermoscopic images of 19 atypical melanocytic nevi from 15 children and young adults (median age 12 years, range 3–26 years). The images were assessed for global dermoscopic patterns at baseline and after a median 25‐month (range 6–138 mos) follow‐up. Ten (52.6%) nevi changed and nine (47.4%) retained a stable dermoscopic pattern. Of the 10 changing lesions, 2 of 4 homogeneous nevi evolved into a reticular pattern and 2 into a mixed pattern; 1 of 2 nevi with a mixed pattern evolved into a homogeneous nevus and 1 into a regressing nevus; 1 of 2 nevi with “other” patterns, such as negative pigment network and peppering throughout the lesion, evolved into a mixed nevus and 1 into a regressing nevus; 1 globular nevus evolved into a mixed pattern; and 1 starburst nevus evolved into a homogeneous nevus. The most striking results of our study were that atypical nevi can evolve into common nevi or they can regress, as documented by long‐term dermoscopic follow‐up. In children and young adults, dermoscopic follow‐up of atypical nevi might be a valid alternative to surgical excision and enables us to achieve new insights into the natural history of these nevi.     

Clinical and dermoscopic stability and volatility of melanocytic nevi in a population-based cohort of children in Framingham school system

Nevi are important risk markers of melanoma. The study aim was to describe changes in nevi of children using longitudinal data from a population-based cohort. Overview back photography and dermoscopic imaging of up to 4 index back nevi was performed at age 11 years (baseline) and repeated at age 14 years (follow-up). Of 443 children (39% females) imaged at baseline, 366 children (39% females) had repeated imaging 3 years later. At age 14, median back nevus counts increased by two; 75% of students (n=274) had at least one new back nevus and 28% (n=103) had at least one nevus that disappeared. Of 936 index nevi imaged dermoscopically at baseline and follow-up, 69% (645 nevi) had retained the same dermoscopic classification from baseline evaluation. Only 4% (n=13) of nevi assessed as globular at baseline were classified as reticular at follow-up, and just 3% (n=3) of baseline reticular nevi were classified as globular at follow-up. Of 9 (1%) index nevi that disappeared at follow-up, none showed halo or regression at baseline. In conclusion, the relative stability of dermoscopic pattern of individual nevi in the face of the overall volatility of nevi during adolescence suggests that specific dermoscopic patterns may represent distinct biological nevus subsets.     

Morphologic changes of acquired melanocytic nevi with eccentric foci of hyperpigmentation ("Bolognia sign") assessed by dermoscopy

BACKGROUND: Melanocytic nevi with eccentric foci of hyperpigmentation ("Bolognia sign") can be considered as a melanoma-simulating type of acquired melanocytic nevus. We report on the morphologic changes of this type of melanocytic nevus over a 39-month period of dermoscopic follow-up. OBSERVATIONS: A 5-year-old girl had a 4-mm brown papule with a peripheral blue-black area on her right upper arm. The eccentric focus of the hyperpigmentation corresponded dermoscopically to a blue-gray area of pigmentation associated with irregular brown-black globules or dots and partially with a superficial black network. After 39 months, a globular type of acquired melanocytic nevus was detectable, which clinically and dermoscopically appeared to be completely benign. A nearly identical situation was observed in 5 other melanocytic nevi, underlining the involution of the pigmented foci in these nevi. The histopathologic diagnoses of 2 lesions were consistent with a compound type of acquired melanocytic nevus with eccentric foci of hyperpigmentation. CONCLUSIONS: Dermoscopy allows identification of a morphologic pathway of modifications, probably typical for this type of melanocytic nevus in children, and therefore enables avoidance of surgical excision with attendant hypertrophic scarring in children. Conversely, in adults, when dermoscopic follow-up of melanocytic nevi reveals eccentric foci of hyperpigmentation, surgical excision of the lesion is indicated.     

Videodermoscopic pattern analysis of acral melanocytic nevi

Three major and three minor types of acral melanocytic lesions have been described: parallel furrow, lattice-like, fibrillar, reticular, homogeneous and globular. To examine the dermoscopic patterns of acral melanocytic lesions and to investigate the association of these patterns with clinical features. This study included 419 acral melanocytic lesions of 295 patients. Dermoscopic images were stored in a standardized digital system and assessed. The incidence rates of the patterns were as follows: parallel furrow (62.5%), reticular (12.2%), globular (7.6%), fibrillar (5.0%), lattice-like (4.3%), homogeneous (3.8%), non-typical (3.8%), globulostreak-like (0.5%) and parallel ridge (0.2%). There was a significant association between pattern and diameter; nevi showing globular pattern were significantly smaller than those showing lattice-like pattern. There was a significant correlation between pattern and localization. The fibrillar pattern was observed more commonly on the feet, and the lattice-like pattern was seen almost entirely on the hands. Homogeneous and globular patterns were proportionately more common on the feet than on the hands. A significant association was found between patterns and colors. Compared with the lattice-like pattern, parallel furrow, fibrillar and homogeneous patterns were lighter in color; the globular pattern was darker than the homogeneous pattern. There was no significant correlations between pattern and clinical presentation. In conclusion, unlike all other studies, in the present study, the two most common patterns following the parallel furrow pattern were reticular and globular, which are minor patterns. Besides the differences in pattern distribution and inherent variability in individual assessment, the age of the study group and location of nevi influence the pattern, possibly in association with race.     

Melanocytic nevi with special features: clinical‐dermoscopic and reflectance confocal microscopic‐findings

Histopathology is considered the ‘gold’ standard for the diagnosis and classification of melanocytic nevi, but the widespread use of in vivo diagnostic technologies such as dermoscopy and reflectance confocal microscopy (RCM), has enriched profoundly the knowledge regarding the morphological variability in nevi. This is because most morphological observations made via these in vivo tools are closely correlated with features seen in histopathology. Dermoscopy has allowed for a more detailed classification of nevi. As such, dermoscopy identifies four main morphologic groups (i.e. globular, reticular, starburst and structureless blue nevi), one group of nevi located at special body sites (i.e. face, acral, nail) and one group of nevi with special features. This latter category consists of nevi of the former categories, which are typified by peculiar clinical‐histopathological findings. They can be subdivided into ‘melanoma simulators’ including combined nevi, recurrent nevi and sclerosing nevus with pseudomelanomatous features, ‘targetoid’ nevi (i.e. halo, cockade, irritated targetoid haemosiderotic and eczematous nevus) and uncommon histopathological variants such as desmoplastic, white dysplastic or ballon cell nevus. While the dermoscopic and RCM patterns of the former categories have been studied in detail, little is currently known about the clinical morphology of the heterogeneous group of ‘special’ nevi. In this article, we describe the clinical, dermoscopic and RCM features of ‘special’ nevi and review the current literature on this group of melanocytic proliferations.     

Predominant dermoscopic patterns observed among nevi

BACKGROUND: It has been clinically observed that patients' "normal" moles resemble each other. Whether this concept is applicable to dermoscopic practice has not been sufficiently studied. OBJECTIVE: To investigate whether physicians evaluating dermoscopic images would identify common dermoscopic profiles of nevi within individual patients. METHODS: Images of 205 nevi belonging to 18 patients were evaluated by 2 dermatologists for dermoscopic global pattern, color, and specific structures. We defined dermoscopic patterns as dominant if seen in >or= 40% of the patient's nevi; a minor pattern was defined as 20 to 39%. RESULTS: A dominant pattern was seen in 15 patients (83%). In 13 (72%) of the patients, >or= 80% of the nevi were classified into one, two, or three global patterns. The reticular global pattern was the most prevalent dominant pattern, seen in 9 patients (50%); the homogeneous pattern was the most prevalent minor pattern, seen in 16 patients (89%). CONCLUSION: Individuals tend to have one to three predominant dermoscopic nevus global patterns.     

Age-related prevalence of dermoscopy patterns in acquired melanocytic naevi

BACKGROUND: Based on the dermoscopic classification of acquired melanocytic naevi, six different dermoscopic types can be distinguished by morphology (globular, globular-reticular, globular-homogeneous, reticular, reticular-homogeneous, homogeneous) and by pigment distribution (uniform, central hyperpigmentation, central hypopigmentation, peripheral hyperpigmentation, peripheral hypopigmentation, multifocal hyper/hypopigmentation). It has been suggested that most individuals harbour one predominant dermoscopic type among their naevi. OBJECTIVES: To evaluate whether the age of the patient influences the predominant naevus pattern observed in individuals with multiple acquired melanocytic naevi. METHODS: Individuals were recruited from the pigmented skin lesion clinic in Graz between July 2000 and February 2001. Individuals with at least 10 melanocytic naevi were selected consecutively until a total of 10 individuals in each of five age groups was obtained. Age groups were: 0-15 years, 16-30 years, 31-45 years, 46-60 years and > 60 years. Digitized images of acquired melanocytic naevi, defined as benign melanocytic proliferations having a diameter of at least 5 mm with a macular component and which were not apparent within the first year of life, were evaluated by dermoscopic criteria. The associations of dermoscopic features as a function of patient age were analysed. We calculated absolute numbers and frequencies, given as percentages, as well as predominance of the dermoscopic types of naevi in the different age groups. RESULTS: Analysis of 1268 naevi revealed that the globular pattern predominated in the youngest age group. By contrast, the reticular and/or homogeneous patterns were increasingly exhibited in naevi from older individuals (older than 15 years). Uniform pigmentation was most common in melanocytic naevi in the youngest age group, while central hyperpigmentation was predominantly seen in the group of individuals aged 16-30 years. CONCLUSIONS: The predominance of dermoscopic types of melanocytic naevi varies according to the individual's age. Awareness of the age-related dermoscopic predominance of melanocytic naevi might allow more accurate recognition of dermoscopic patterns of melanocytic skin lesions that are unusual with respect to the individual's age. This observation may help in the early recognition of some 'banal'-appearing melanomas. Furthermore, the observations made in this study raise interesting questions regarding naevus evolution.     

Three years dermoscopic follow‐up of atypical nevi

Atypical nevi are dynamic lesions and may progressively transform into more or less atypical lesions. We aimed to investigate the dermoscopic features of atypical nevi and dynamic changes in these lesions over a period of 3‐years. Patients with 3‐year dermoscopic follow‐up records were enrolled in the study. We compared the dermatoscopic features of the nevus recorded in the first dermoscopic examination and at the end of the third year. Changes in size (mm), pattern, and color were investigated. The most common dermoscopic patterns were reticular (18 patients; 34%), reticular‐homogeneous (17 patients; 32.1%), and reticular‐globular (7 patients; 13.2%). The most common pigmentation patterns were central hyperpigmentation (28 patients; 52.8%), regular pigmentation (nine patients; 17.0%), and multifocal hypo/hyperpigmentation (eight patients; 15.1%). Twenty‐one (39.6%) patients showed changes in pattern. The transformation from reticular‐homogeneous pattern to the homogeneous pattern was the most frequent change in pattern (7 of 21 patients; 33.3%). The transformation from reticular pattern to reticular‐homogeneous pattern was the second most common change in pattern (5 of 21 patients; 23.8%). Fourteen (26.4%) patients experienced symmetrical enlargement. Symmetrical enlargement was statistically more frequent in patients who showed dermoscopic changes in pattern than in those who did not show any changes in the pattern (p: .038). In this study, we did not observe any new dermoscopic clues for the diagnosis of melanoma during the follow‐up. The nevi tended to turn into a homogeneous (structureless) pattern. We observed that the most common dermoscopic change in pattern was the transformation from reticular‐homogeneous pattern to homogeneous pattern, and the lesions had symmetrical enlargement during this transformation. In conclusion, despite the known association between atypical nevi and the risk of developing melanoma, most atypical nevi do not transform into melanoma. Therefore, our study suggests that the excision of atypical nevi is not necessary and dermatoscopic follow‐up can reduce the number of unnecessary excisions.     

Dermoscopic patterns of acral melanocytic nevi and melanomas in a white population in central Italy

OBJECTIVE: To investigate the dermoscopic features of acral melanocytic lesions in a white population in central Italy. DESIGN: Retrospective review. SETTING: University dermatology department. PATIENTS: Six hundred fifty-one Italian subjects, ranging in age from 6 months to 78 years. MAIN OUTCOME MEASURES: We retrospectively investigated all digital dermoscopic images of acral melanocytic lesions included in our database from January 1996 to May 2005. RESULTS: We retrieved digital images of 723 benign acral melanocytic lesions in 641 patients (235 males and 406 females; mean age, 26.5 years) and of 10 acral melanomas in 10 patients (7 males and 3 females; mean age, 65 years). Individual lesions were located on the soles (n=520), fingers (n=146), and palms (n=67). Among acral nevi, the parallel furrow (42.1%) was the most common pattern, followed by the latticelike (14.9%), nontypical (13.7%), fibrillar (10.8%), homogeneous (9.3%), globular (5.4%), and reticular (2.1%) patterns. The frequency of distribution of the latticelike, nontypical, fibrillar, and homogeneous patterns significantly differed (P<.001, P=.03, P<.001, and P=.03, respectively) between anatomical sites. Also, 13 acral nevi (1.8%), mainly located on the fingers, showed a new combined pattern (transition pattern) consisting of a brownish black network associated with a parallel furrow or latticelike pattern. All 10 acral melanomas showed a multicomponent dermoscopic pattern. CONCLUSIONS: In our series of acral nevi, we observed 8 dermoscopic patterns, with varying distribution by anatomical site. Identification of a specific pattern is highly suggestive of the benign or the malignant nature of any given acral melanocytic lesion.     

Unna's and Miescher's nevi: two different types of intradermal nevus: hypothesis concerning their histogenesis

In 1991, we tentatively introduced the classification of Ackerman and Magana-García for acquired melanocytic nevi in our laboratory. We soon realized that every acquired intradermal melanocytic nevus might be easily classified into either Unna's or Miescher's patterns and that this classification had both clinical implications and significant histological differences. The decisive discriminative feature between Unna's and Miescher's nevi is that Unna's nevus is an almost purely adventitial lesion confined to expanded papillary dermis and, many times, to the perifollicular dermis too. In Miescher's nevus melanocytes diffusely infiltrate both adventitial and reticular dermis in a wedge-shaped pattern. With these concepts in mind, every acquired intradermal melanocytic nevus can be easily classified as either Unna's or Miescher's. We studied 751 acquired melanocytic nevi; 458 (61%) of them were intradermal; of these, 234 were Unna's nevi and 224 were Miescher's nevi. Eighty- three per cent of the nevi from the head and neck were intradermal nevi, whereas on the trunk and limbs junction and compound nevi were the most frequent (56%). When intradermal nevi were divided into Unna's and Miescher's patterns, it resulted that 91% of Miescher's nevi located on the face and 94% of intradermal nevi on the face were Miescher's nevi. In contradistinction, 87% of the Unna's nevi located on the neck, trunk, and limbs, and 96% of intradermal nevi from these locations were Unna's nevi. Only on the scalp was there no clear predominance of one type of intradermal nevus. A series of other histological characteristics were significantly predominant (P = 0.000) in either Unna's or Miescher's nevi. Unna's nevi had more: junctional nests above the intradermal component (40% versus 20%), a radial pattern of intradermal nests (38% versus 0%), vascular-like clefts lined by nevus cells (48% versus 4%), and in depth maturation (94% versus 0%). Miescher's nevi had more: pilosebaceous follicles within the nevus (100% versus 51%), subnevis folliculitis (12% versus 1%), large isolated melanocytes along the basal epidermal layer (47% versus 11%), multinucleated nevocytes (89% versus 44%), and adipocytes within the nevus (53% versus 11%). In conclusion, Unna's and Miescher's nevi are 2 subsets of acquired melanocytic nevus with clinical implications and significant histological differences. A histogenetic hypothesis is proposed on the basis of their histological structure.     

Dermoscopic Evolution of Pediatric Nevi

BackgroundThe incidence of pediatric melanoma is very rare. Dermoscopic features help to distinguish pediatric melanoma and common nevi.ObjectiveTo study the evolution of dermoscopic findings in benign nevi in childhood through serial observation and photography.MethodsWe examined 504 melanocytic lesions in 100 patients. From each participant, dermoscopic images of the nevi from 4-year dermoscopic follow-up were obtained, including randomly selected nevi.ResultsThe most common dermoscopic patterns were homogeneous (193 nevi; 38.3%), globular (92 nevi; 18.3%), and reticular (86 nevi; 17.1%). Dermoscopic pattern changes were detected in 27% of patients aged 2~10 years and in 20% of patients aged 11~16 years. The main pattern changes consisted of the transition from homogeneous to globular-homogeneous (16%), from homogeneous to reticular-homogeneous (12%) and from globular to globular-homogeneous (10%). Although 257 of the 504 nevi (51.0%) have stable duration without size changes, 169 of the 504 nevi (33.5%) were enlarged, and 78 of the 504 nevi (15.5%) had become smaller.ConclusionThese results contrast with the prevailing view that dermoscopic patterns in pediatric nevi are usually characterized by globular patterns and that melanocytic nevi generally undergo a characteristic transition from a globular pattern to a reticular pattern. Fifty one percent of patients did not exhibit a size change. While 33% of patients had symmetrical enlargement, 15% of patients had involution. Therefore, enlargement is a common dermoscopic change in pediatric nevi, and is not a specific sign of pediatric melanoma.     

The spectrum of Spitz nevi: a clinicopathologic study of 83 cases

OBJECTIVE: To achieve a clinicopathologic classification of Spitz nevi by comparing their clinical, dermoscopic, and histopathologic features. DESIGN: Eighty-three cases were independently reviewed by 3 histopathologists and preliminarily classified into classic or desmoplastic Spitz nevus (CDSN, n = 11), pigmented Spitz nevus (PSN, n = 14), Reed nevus (RN, n = 16), or atypical Spitz nevus (ASN, n = 14); the remaining 28 cases were then placed into an intermediate category (pigmented Spitz-Reed nevus, PSRN) because a unanimous diagnosis of either PSN or RN was not reached. SETTING: University dermatology and pathology departments and general hospital pathology departments. PATIENTS: A sample of subjects with excised melanocytic lesions. MAIN OUTCOME MEASURE: Frequency of dermoscopic patterns within the different histopathologic subtypes of Spitz nevi. RESULTS: Overlapping clinical, dermoscopic, and histopathologic findings were observed among PSN, RN, and PSRN, thereby justifying their inclusion into the single PSRN diagnostic category. Asymmetry was the most frequent indicator of histopathologic ASN (79%; n = 11); in only 4 cases did dermoscopic asymmetry show no histopathologic counterpart, and in those cases the discrepancy was probably the result of an artifact of the gross sampling technique carried out with no attention to the dermoscopic features. CONCLUSIONS: Among Spitz nevi, histopathologic distinction between PSN and RN is difficult, not reproducible, and may be clinically useless. A simple clinicopathologic classification of these neoplasms might therefore be structured as CDSN, PSRN, and ASN. Asymmetry should be assessed using both dermoscopic and histopathologic analysis, and reliability in histopathologic diagnosis may be enhanced by the simultaneous evaluation of the corresponding dermoscopic images.     

BRAF mutations are common somatic events in melanocytic nevi

We determined mutations in the BRAF, N-ras, and CDKN2A genes in 27 histologically diverse melanocytic nevi and corresponding surrounding tissues from 17 individuals. Mutations in the BRAF and N-ras gene were found in 22 nevi (81%) from 16 individuals (94%). The predominant BRAF mutation T1799A (V600E) was detected in 18 nevi; 1 nevus had a novel A1781G (D594V) mutation in the same gene and 3 nevi had mutations in codon 61 of the N-ras gene. In 4 individuals both nevi carried a BRAF mutation, whereas in 2 other individuals 1 nevus showed a BRAF mutation and the second nevus had an N-ras mutation. In 2 individuals normal skin distant from nevi showed a BRAF mutation. No mutations were detected in the CDKN2A gene. The mutations in the BRAF and N-ras genes, in this study, were not associated with histologic type, location, skin type, size, or numbers of nevi. Our results suggest that mutations in the BRAF gene and to some extent in the N-ras gene represent early somatic events that occur in melanocytic nevi. We hypothesize the dual effect of solar ultraviolet irradiation on melanoma, through mutagenesis and by increasing the number of melanocytic nevi, many of which carry a BRAF or N-ras mutation.     

Clinical and dermoscopic features of small Reed nevus (<6 mm)

Background The differential diagnosis between Reed nevi and melanoma becomes more difficult if the lesion to analyse presents a small size, with a diameter of 6 mm or smaller. Many studies have reported various dermoscopic features of Reed nevi during their growth phases. In early stages of evolution, the lesions generally show a characteristic globular appearance typically found in childhood, followed by the so‐called starburst pattern. Objective The aim of the study was to identify the main dermoscopic features in small Reed nevi (<6 mm in size). Methods Using a computerized skin‐imaging database for melanoma prevention surgery at the Department of Dermatology of the University of Florence, 15 Reed nevi were selected among 103 small (<6 mm) melanocytic lesions consecutively excised. Images of small Reed nevi, independently blinded to histopathological diagnosis, were administered to a dermatologist expert in dermoscopy, who separately examined the clinical and the dermatoscopic images of small Reed nevi and evaluated their clinical and dermoscopic parameters. Results Analysis of the main dermoscopic patterns showed that 40% had a reticular pattern, 20% had a starburst pattern, 6.5% had a globular pattern, 6.5% had a homogeneous pattern and 27% had an atypical pattern. Conclusion We propose that small, early‐stage Reed nevus are not characterized by an evolution of growth patterns to a phenotype typical of larger lesions. We assume that the patterns are distributed in a linear manner between age groups, may all be present at the outset and thus are independent from the various stages of nevus development.     

A dual concept of nevogenesis:Theoretical considerations based on dermoscopic features of melanocytic nevi

The dermoscopic features of melanocytic nevi in children are clearly different from those in adults. While nevi in children show almost exclusively globular patterns, those in adults usually exhibit reticular patterns. These remarkable differences could be explained by a dual concept of nevogenesis, based on current clinico‐epidemiologic, dermoscopic, histopathologic and genetic data.     

Large atypical melanocytic nevi in recessive dystrophic epidermolysis bullosa: clinicopathological, ultrastructural, and dermoscopic study

A 3-year-old boy with recessive dystrophic epidermolysis bullosa developed a rapidly growing, large, acquired irregular melanocytic nevus on the lower aspect of the back. The lesion was clinically atypical and fulfilled the criteria for a malignant melanocytic proliferation. A complete surgical excision was performed. Histopathologic examination disclosed a compound melanocytic nevus without melanocytic atypia. Ultrastructural examination showed melanocytic cells located both at the roof and the floor of the blister. Several months later, three pigmentary lesions with a similar clinical appearance developed. Periodic clinical and dermoscopic examinations were recommended. Dermoscopic examination disclosed a globular pattern with brown globules and black dots distributed all over the lesions. The lesions also exhibited blue-greyish dots and multiple rounded white structures corresponding to milia-like cysts. No dermoscopic features suggestive of malignancy were noted. Acquired melanocytic nevi showing atypical clinical features have been reported to occur in areas of blistering in patients with epidermolysis bullosa. These nevi appear as large, asymmetrical pigmentary lesions with irregular borders. Initially, they are very dark in pigmentation, with color variegation and loss of pigment, and even becoming papillomatous over time. Histopathologic examination can show features of compound/junctional nevus as well as persistent/recurrent nevus. The concept of "epidermolysis bullosa nevus" has been proposed to define these peculiar lesions. The clinical, histopathologic and ultrastructural features of these nevi are reviewed. The usefulness of dermoscopic examination in the routine diagnosis and follow-up of these lesions are stressed.