The long-term evolution of melanocytic nevi among high-risk adults.

BACKGROUND: There is little understanding regarding the long-term natural history of melanocytic nevi among adults. OBJECTIVE: The objective of the study was to describe the long-term natural history of individual nevi located on the torso of high-risk patients. METHODS: All patients attending Memorial Sloan Kettering Cancer Center (MSKCC) who underwent two total body photography (TBP) sessions 15+ years apart were included ('retrospective' group). To account for a potential selection bias, we also included consecutive patients who had TBP 15+ years ago and consented to undergo follow-up TBP ('prospective' group). We compared baseline and follow-up torso images on the TBPs and evaluated the number of total, new and disappearing nevi; number of seborrheic keratoses and actinic keratoses; each nevus' diameter at both time points; each nevus' colour change; the presence of clinical atypia; and when dermoscopy was available, the dermoscopic features at each time point. RESULTS: One hundred six patients were included in the study. Although the average age of the patients was 40 at baseline TBP, most patients developed new nevi between imaging sessions (median 16.4 years) with an average of 2.6 (SD = 4.8) nevi per participant. The average number of disappearing nevi was 0.3 (SD = 0.6). In addition, 62/106 (58%) patients had an absolute increase, and 9/106 (8%) patients had an absolute decrease in their total nevus count. Roughly half (49%: 1416/2890) of the nevi that could be evaluated at both time points increased in diameter by at least 25%. Only 6% (159/2890) of nevi shrunk in diameter by at least 25%. Patients with a history of melanoma had a higher rate of disappearing nevi, and their nevi were more likely to grow. Most nevi demonstrated no significant dermoscopic changes. CONCLUSIONS: High-risk patients acquire new nevi throughout life with very few nevi disappearing over time. Contrary to prior reports, most nevi in adults increase in diameter, while few nevi shrink.

The differences in clinical and dermoscopic features between in situ and invasive nevus-associated melanomas and de novo melanomas.

BACKGROUND: Nevus-associated melanomas (NAM) account for 30% of all melanomas and are associated with younger age and with thinner Breslow thickness. Previous studies of NAM dermoscopy found conflicting results. OBJECTIVE: To compare the clinical and dermoscopic features of NAM and de novo melanomas (DNM), stratified by melanoma thickness, in a relatively large cohort of patients. METHODS: A cross-sectional study of all melanomas biopsied between 2004 and 2019 at a large cancer centre. Lesions were categorized as in situ and invasive NAM or DNM. Dermoscopic images were reviewed and annotated. Associations between melanoma subtype and dermoscopic features were analysed via logistic regression modelling. Bivariate analyses were conducted using non-parametric bootstrap and chi-squared methods. RESULTS: The study included 160 NAM (86 in situ and 74 invasive) and 218 DNM (109 in situ and 109 invasive). NAM were associated with younger age, greater likelihood of being present on the torso, and thinner Breslow thickness. NAM were 2.5 times more likely to show a negative pigment network than DNM. In situ NAM were 2.1 and two times more likely to display dermoscopic area without definable structures and tan structureless areas than DNM, respectively. In situ melanomas were more likely to present a pigment network, and invasive melanomas more commonly presented scar-like depigmentation and shiny white structures. Streaks, blotches and shiny white structures were associated with deeper Breslow depth. CONCLUSIONS: Even though the nevus component of NAM could not be identified dermoscopically in the current series, negative pigment network, tan structureless areas and areas without definable structures are dermoscopic clues for NAM.

Human surface anatomy terminology for dermatology: a Delphi consensus from the International Skin Imaging Collaboration.

BACKGROUND: There is no internationally vetted set of anatomic terms to describe human surface anatomy. OBJECTIVE: To establish expert consensus on a standardized set of terms that describe clinically relevant human surface anatomy. METHODS: We conducted a Delphi consensus on surface anatomy terminology between July 2017 and July 2019. The initial survey included 385 anatomic terms, organized in seven levels of hierarchy. If agreement exceeded the 75% established threshold, the term was considered 'accepted' and included in the final list. Terms added by the participants were passed on to the next round of consensus. Terms with <75% agreement were included in subsequent surveys along with alternative terms proposed by participants until agreement was reached on all terms. RESULTS: The Delphi included 21 participants. We found consensus (≥75% agreement) on 361/385 (93.8%) terms and eliminated one term in the first round. Of 49 new terms suggested by participants, 45 were added via consensus. To adjust for a recently published International Classification of Diseases-Surface Topography list of terms, a third survey including 111 discrepant terms was sent to participants. Finally, a total of 513 terms reached agreement via the Delphi method. CONCLUSIONS: We have established a set of 513 clinically relevant terms for denoting human surface anatomy, towards the use of standardized terminology in dermatologic documentation.

Dermatoscopic features of thin (≤2 mm Breslow thickness) vs. thick (>2 mm Breslow thickness) nodular melanoma and predictors of nodular melanoma versus nodular non-melanoma tumours: a multicentric collaborative study by the International Dermoscopy Society.

BACKGROUND: Thin nodular melanoma (NM) often lacks conspicuous melanoma-specific dermatoscopic criteria and escapes clinical detection until it progresses to a thicker and more advanced tumour. OBJECTIVE: To investigate the dermatoscopic morphology of thin (≤2 mm Breslow thickness) vs. thick (>2 mm) NM and to identify dermatoscopic predictors of its differential diagnosis from other nodular tumours. METHODS: Retrospective, morphological case-control study, conducted on behalf of the International Dermoscopy Society. Dermatoscopic images of NM and other nodular tumours from 19 skin cancer centres worldwide were collected and analysed. RESULTS: Overall, 254 tumours were collected (69 NM of Breslow thickness ≤2 mm, 96 NM >2 mm and 89 non-melanoma nodular lesions). Light brown coloration (50.7%) and irregular brown dots/globules (42.0%) were most frequently observed in ≤2 mm NMs. Multivariate analysis revealed that dotted vessels (3.4-fold), white shiny streaks (2.9-fold) and irregular blue structureless area (2.4-fold) were predictors for thinner NM compared to non-melanoma nodular tumours. Overall, irregular blue structureless area (3.4-fold), dotted vessels (4.6-fold) and serpentine vessels (1.9-fold) were predictors of all NM compared to non-melanoma nodular lesions. LIMITATIONS: Absence of a centralized, consensus pathology review and cases selected form tertiary centres maybe not reflecting the broader community. CONCLUSIONS: Our study sheds light into the dermatoscopic morphology of thin NM in comparison to thicker NM and could provide useful clues for its differential diagnosis from other non-melanoma nodular tumours.

Standardization of dermoscopic terminology and basic dermoscopic parameters to evaluate in general dermatology (non-neoplastic dermatoses): an expert consensus on behalf of the International Dermoscopy Society.

BACKGROUND: Over the last few years, several articles on dermoscopy of non-neoplastic dermatoses have been published, yet there is poor consistency in the terminology among different studies. OBJECTIVES: We aimed to standardize the dermoscopic terminology and identify basic parameters to evaluate in non-neoplastic dermatoses through an expert consensus. METHODS: The modified Delphi method was followed, with two phases: (i) identification of a list of possible items based on a systematic literature review and (ii) selection of parameters by a panel of experts through a three-step iterative procedure (blinded e-mail interaction in rounds 1 and 3 and a face-to-face meeting in round 2). Initial panellists were recruited via e-mail from all over the world based on their expertise on dermoscopy of non-neoplastic dermatoses. RESULTS: Twenty-four international experts took part in all rounds of the consensus and 13 further international participants were also involved in round 2. Five standardized basic parameters were identified: (i) vessels (including morphology and distribution); (ii) scales (including colour and distribution); (iii) follicular findings; (iv) 'other structures' (including colour and morphology); and (v) 'specific clues'. For each of them, possible variables were selected, with a total of 31 different subitems reaching agreement at the end of the consensus (all of the 29 proposed initially plus two more added in the course of the consensus procedure). CONCLUSIONS: This expert consensus provides a set of standardized basic dermoscopic parameters to follow when evaluating inflammatory, infiltrative and infectious dermatoses. This tool, if adopted by clinicians and researchers in this field, is likely to enhance the reproducibility and comparability of existing and future research findings and uniformly expand the universal knowledge on dermoscopy in general dermatology. What's already known about this topic? Over the last few years, several papers have been published attempting to describe the dermoscopic features of non-neoplastic dermatoses, yet there is poor consistency in the terminology among different studies. What does this study add? The present expert consensus provides a set of standardized basic dermoscopic parameters to follow when evaluating inflammatory, infiltrative and infectious dermatoses. This consensus should enhance the reproducibility and comparability of existing and future research findings and uniformly expand the universal knowledge on dermoscopy in general dermatology.

A comparative dermoscopic and reflectance confocal microscopy study of naevi and melanoma with negative pigment network.

BACKGROUND: Negative pigment network (NPN) is a dermoscopic structure observed more frequently among melanomas than naevi. Precise tissue correlates of NPN are still elusive. OBJECTIVE: To describe the reflectance confocal microscopy (RCM) findings underlying NPN in melanocytic neoplasms. METHODS: We retrospectively identified all melanocytic neoplasms displaying dermoscopic NPN that were imaged with RCM and subsequently biopsied between 2011 and 2015. Images from study lesions (n = 50) were evaluated for dermoscopic and RCM Criteria. Histopathological correlational study was performed in a subset of cases (n = 15). RESULTS: The study data set consisted of 21 melanomas (42%) and 29 naevi (58%). Melanomas showed more frequently irregularly shaped globules than naevi (62% vs. 28%, P = 0.03); NPN also tended to be more asymmetrically located among melanomas (86%) than naevi (62%), albeit not significant (P = 0.06). Under RCM, we observed three patterns of dermal papillae (DP): (i) 'Dark DP' - whereby DP were devoid of nests and often surrounded by a junctional proliferation as thick-Rings - this pattern was less common among melanomas (n = 10, 48%) than naevi (n = 23, 79%, P = 0.02); (ii) 'Bulging DP' - whereby junctional nests of melanocytes protrude into the DP, often in association with junctional proliferation as Meshwork - with comparable frequency among melanomas (n = 12, 57%) and naevi (n = 23, 79%, P = 0.09) and (iii) 'Expanded DP' - whereby junctional and/or dermal nests filled and expanded the DP, often in association with dermal-epidermal junction (DEJ) Clod pattern - seen more commonly among melanomas (n = 15, 71%) than naevi (n = 6, 21%, P < 0.001). Dermoscopy-RCM correlation and comparison to histopathological findings show that the hypo-pigmented lines of NPN correlate with broadened epidermal retes, which often show overlying surface dells and wedge-shaped hypergranulosis, while the pigmented globules of NPN correlate with a predominantly-junctiona of melanocytes along and between the elongated retes. CONCLUSIONS: Dermoscopic NPN correlates with three DEJ RCM patterns with differing frequency between naevi and melanomas.

Dermoscopy of naevi in patients with oculocutaneous albinism.

Oculocutaneous albinism (OCA) increases predisposition to skin malignancies. Nevertheless, the differential diagnosis between melanoma and naevi in patients with OCA is still challenging, because pigmentary lesions have rarely been described in this population. We aimed to describe the dermoscopic patterns of naevi in patients with OCA. We prospectively evaluated 83 naevi from 37 patients with OCA in a single centre in Brazil. Lesions were analysed by eye and by dermoscopy and were grouped by dermoscopic pattern. Eight main patterns were identified: homogeneous structureless pattern (n = 28; 33.7%), globular pattern (n = 27; 32.5%), reticular pattern (n = 8; 9.6%), peripheral reticular pattern with central hypopigmentation (n = 8; 9.6%), peripheral globules (n = 8; 9.6%), irregular brown globules with pink background (n = 2; 2.4%), reticular globular disorganized pattern (n = 1; 1.2%) and peripheral reticular globular with central hypopigmentation (n = 1; 1.2%). We found previously undescribed dermoscopic patterns in patients with OCA, in addition to confirming previously described patterns. These descriptions may help the understanding of pigmented naevi in patients with OCA.

Accuracy of tele-consultation on management decisions of lesions suspect for melanoma using reflectance confocal microscopy as a stand-alone diagnostic tool.

BACKGROUND: Diagnostic accuracy of reflectance confocal microscopy (RCM) as a stand-alone diagnostic tool for suspect skin lesions has not been extensively studied. OBJECTIVE: Primary aim was to measure experts' accuracy in RCM-based management decisions. Secondary aim was to identify melanoma-specific RCM features. METHODS: The study enrolled patients ≥18 years that underwent biopsy of skin lesions clinically suspected to be melanoma. One hundred lesions imaged by RCM were randomly selected from 439 lesions prospectively collected at four pigmented lesion clinics. The study data set included 23 melanomas, three basal cell and two squamous cell carcinomas, 11 indeterminate melanocytic lesions and 61 benign lesions including 50 nevi. Three expert RCM evaluators were blinded to clinical or dermoscopic images, and to the final histopathological diagnosis. Evaluators independently issued a binary RCM-based management decision, 'biopsy' vs. 'observation'; these decisions were scored against histopathological diagnosis, with 'biopsy' as the correct management decision for malignant and indeterminate lesions. A subset analysis of 23 melanomas and 50 nevi with unequivocal histopathological diagnosis was performed to identify melanoma-specific RCM features. RESULTS: Sensitivity, specificity and diagnostic accuracy were 74%, 67% and 70% for reader 1, 46%, 84% and 69% for reader 2, and 72%, 46% and 56% for reader 3, respectively. The overall kappa for management decisions was 0.34. Readers had unanimous agreement on management for 50 of the 100 lesions. Non-specific architecture, non-visible papillae, streaming of nuclei, coarse collagen fibres and abnormal vasculature showed a significant association with melanoma in the evaluation of at least two readers. CONCLUSIONS: Reflectance confocal microscopy tele-consultation of especially challenging lesions, based on image review without benefit of clinical or dermoscopy images, may be associated with limited diagnostic accuracy and interobserver agreement. Architectural and stromal criteria may emerge as potentially useful and reproducible criteria for melanoma diagnosis.

The smart approach: feasibility of lentigo maligna superficial margin assessment with hand-held reflectance confocal microscopy technology.

BACKGROUND: Lentigo maligna may be challenging to clear surgically. OBJECTIVE: To evaluate feasibility of using superficial skin cuts as RCM imaging anchors for attaining negative surgical margins in lentigo maligna. METHODS: Included patients presented with lentigo maligna near cosmetically sensitive facial structures. We evaluated, with hand-held-RCM, microscopic clearance of melanoma beyond its dermoscopically detected edges. Evaluated margins were annotated using shallow skin cuts. If a margin was positive at 'first-step' RCM evaluation, we sequentially advanced the margin radially outward at that segment by 2-mm intervals until an RCM-negative margin was identified. Prior to final surgical excision, we placed sutures at the outmost skin cuts to allow comparison of RCM and histopathological margin assessments. Primary outcome measure was histopathological verification that RCM-negative margins were clear of melanoma. RESULTS: The study included 126 first-step margin evaluations in 23 patients, median age 70 years (range: 43-91). Seventeen patients (74%) had primary in-situ melanoma and six (26%) invasive melanoma, mean thickness 0.3 mm (range 0.2-0.4 mm). Six cases (26%) showed complete negative RCM margins on 'first-step', 11 (48%) were negative at 'second-step', and four (17%) at 'third-step'. In two additional cases (9%), margins clearance could not be determined via RCM due to widespread dendritic cells proliferation. The RCM-negative margins in all 21 cases proved clear of melanoma on histopathology. Of the 15 cases that returned at 1-year follow-up, none showed any residual melanoma on dermoscopic and RCM examinations. Interobserver reproducibility showed fair agreement between bedside RCM reader and blinded remote-site reader, with Spearman's rho of 0.48 and Cohen's kappa of 0.43; using bedside reader as reference, the remote reader's sensitivity was 92% and specificity 57% in positive margin detection. CONCLUSIONS: Margin mapping of lentigo maligna with hand-held-RCM, using superficial skin cuts, appears feasible. This approach needs validation by larger studies.

Dermoscopy and the diagnosis of primary cutaneous B-cell lymphoma.

BACKGROUND: Primary cutaneous B-cell lymphomas (PCBCLs) are frequently misdiagnosed, and a biopsy is needed to attain the correct diagnosis. OBJECTIVE: To characterize the dermoscopic features of PCBCL. METHODS: In this retrospective observational study, we analysed the pathology reports of 172 newly diagnosed PCBCL for the initial clinical differential diagnosis. The dermoscopic images of 58 PCBCL were evaluated for dermoscopic features. Two dermoscopy experts, who were blinded to the diagnosis and the study objective, evaluated images from 17 cases for a dermoscopic differential diagnosis. RESULTS: Of 172 biopsy-proven PCBCL lesions, cutaneous lymphoma was suspected by the clinician in 16.3%; the leading diagnosis was basal cell carcinoma in 17.4%, and other skin neoplasms in 21%. Studying 58 PCBCL dermoscopic images, we most frequently identified salmon-coloured background/area (79.3%) and prominent blood vessels (77.6%), mostly of serpentine (linear-irregular) morphology (67.2%). Dermoscopic features did not differ significantly by subtype or location. Blinded evaluation by dermoscopy experts raised a wide differential diagnosis including PCBCL, arthropod bite, basal cell carcinoma, amelanotic melanoma and scar/keloid. CONCLUSIONS: Two dermoscopic features, salmon-coloured area/background and serpentine vessels, are frequently seen in PCBCL lesions. These characteristic dermoscopic features, although not specific, can suggest a possible diagnosis of PCBCL.

Clinical and dermoscopic clues to differentiate pigmented nail bands: an International Dermoscopy Society study.

BACKGROUND: Longitudinal melanonychia might be difficult to differentiate and the use of dermoscopy can be useful for the preoperative evaluation and management decision. OBJECTIVES: The aim of our study was to investigate clinical and dermoscopic criteria of acquired longitudinal melanonychia in adults to identify the best predictors of melanoma using a multivariate analysis and to explore eventual new dermoscopic criteria for nail melanoma diagnosis. METHODS: In this retrospective observational study, 82 histopathologically diagnosed, acquired nail pigmented bands were collected and examined. All variables were included in the analysis and examined as possible predictors of nail melanoma. Both univariate and multivariable analyses have been performed. RESULTS: Among 82 cases, 25 were diagnosed as nail melanoma and 57 as benign lesions (including 32 melanocytic nevi and 25 benign melanocytic hyperplasia). Melanoma cases were significantly associated with a width of the pigmented band higher than 2/3 of the nail plate, grey and black colours, irregularly pigmented lines, Hutchinson and micro-Hutchinson signs, and nail dystrophy. Granular pigmentation, a newly defined dermoscopic criterion, was found in 40% of melanomas and only in 3.51% of benign lesions. CONCLUSIONS: Dermoscopic examination of longitudinal melanonychia provides useful information that could help clinicians to improve melanoma recognition.

Cross-sectional analysis of the dermoscopic patterns and structures of melanocytic naevi on the back and legs of adolescents.

BACKGROUND: Junctional (flat) naevi predominate on the extremities, whereas dermal (raised) naevi are found primarily on the head, neck and trunk. Few studies have investigated the anatomical site prevalence of melanocytic naevi categorized using dermoscopy. OBJECTIVES: To identify the prevalence of dermoscopic patterns and structures of naevi from the back and legs of adolescents. METHODS: Dermoscopic images of acquired melanocytic naevi were obtained from the back and legs of students from a population-based cohort in Framingham, Massachusetts. Naevi were classified into reticular, globular, homogeneous or complex dermoscopic patterns. Multinomial logistic regression modelling assessed the associations between dermoscopic pattern and anatomical location. RESULTS: In total 509 participants (mean age 14 years) contributed 2320 back naevi and 637 leg naevi. Compared with homogeneous naevi, globular and complex naevi were more commonly observed on the back than the legs [odds ratio (OR) 29·39, 95% confidence interval (CI) 9·53-90·65, P < 0·001 and OR 6·8, 95% CI 2·7-17·14, P < 0·001, respectively], whereas reticular lesions were less likely to be observed on the back than on the legs (OR 0·67, 95% CI 0·54-0·84, P = 0·001). Naevi containing any globules were more prevalent on the back than on the legs (25% vs. 3·6%, P < 0·001). Naevi containing any network were more prevalent on the legs than on the back (56% vs. 40·6%, P < 0·001). CONCLUSIONS: These findings add to a robust body of literature suggesting that dermoscopically defined globular and reticular naevi represent biologically distinct naevus subsets that differ in histopathological growth pattern, age- and anatomical-site-related prevalence, molecular phenotype and aetiological pathways.

Reflectance confocal microscopy in the diagnosis of solitary pink skin tumours: review of diagnostic clues.

Reflectance confocal microscopy (RCM) is a noninvasive tool that can be helpful in the diagnosis of nonpigmented skin tumours. As RCM enables visualization of architectural and cytological structures at near-histological resolution, it can improve the diagnostic accuracy of dermoscopically equivocal solitary pink neoplasms. For management decisions, it is important to identify specific morphological clues that allow bedside classification of nonpigmented skin neoplasms into benign vs. malignant and melanocytic vs. nonmelanocytic. More specifically, the presence of a nested melanocytic proliferation at the dermoepidermal junction or dermis level permits the clinician to ascribe a given lesion as melanocytic; the identification of basaloid bright tumour islands is a key RCM feature for the diagnosis of basal cell carcinoma; and the presence of disarrayed epidermis along with small demarcated papillae is suggestive for the diagnosis of squamous cell carcinoma. The present review offers a comprehensive description of the main RCM diagnostic clues for solitary pink neoplasms that direct clinicians to the correct diagnosis and that may serve as groundwork for future prospective studies.

Genetic factors associated with naevus count and dermoscopic patterns: preliminary results from the Study of Nevi in Children (SONIC).

BACKGROUND: Melanocytic naevi are an important risk factor for melanoma. Naevi with distinct dermoscopic patterns can differ in size, distribution and host pigmentation characteristics. OBJECTIVES: We examined MC1R and 85 other candidate loci in a cohort of children to test the hypothesis that the development and dermoscopic type of naevi are modulated by genetic variants. METHODS: Buccal DNAs were obtained from a cohort of 353 fifth graders (mean age 10·4 years). Polymorphisms were chosen based on a known or anticipated role in naevi and melanoma. Associations between single-nucleotide polymorphisms (SNPs) and baseline naevus count were determined by multivariate regression adjusting for sex, race/ethnicity and sun sensitivity. Dermoscopic images were available for 853 naevi from 290 children. Associations between SNPs and dermoscopic patterns were determined by polytomous regression. RESULTS: Four SNPs were significantly associated with increasing (IRF4) or decreasing (PARP1, CDK6 and PLA2G6) naevus count in multivariate shrinkage analyses with all SNPs included in the model; IRF4 rs12203952 showed the strongest association with log naevus count (relative risk 1·56, P < 0·001). Using homogeneous naevi as the reference, IRF4 rs12203952 and four other SNPs in TERT, CDKN1B, MTAP and PARP1 were associated with either globular or reticular dermoscopic patterns (P < 0·05). CONCLUSIONS: Our results provide evidence that subsets of naevi defined by dermoscopic patterns differ in their associations with germline genotypes and support the hypothesis that dermoscopically defined subsets of naevi are biologically distinct. These results require confirmation in larger cohorts. If confirmed, these findings will improve the current knowledge of naevogenesis and assist in the identification of individuals with high-risk phenotypes.

Accuracy of in vivo confocal microscopy for diagnosis of basal cell carcinoma: a comparative study between handheld and wide-probe confocal imaging.

BACKGROUND: Reflectance confocal microscopy (RCM) increases specificity of identification of basal cell carcinoma (BCC). A smaller-diameter handheld RCM (HH-RCM) allows better access to limited anatomic locations. OBJECTIVE: To compare accuracy of HH-RCM in identification of BCC to that of traditional wide-probe RCM (TWP-RCM). METHODS: Patients presenting at least one lesion clinically and dermoscopically suspicious for BCC, were recruited from two dermatology skin cancer clinics. Prior to excision, we attempted to image all lesions with HH-RCM and TWP-RCM using a standardized protocol. RCM images were retrospectively evaluated, jointly by two blinded readers. For purposes of comparative RCM, sensitivity and specificity analysis, we used a threshold of ≥3 RCM criteria to identify BCC, whereby at least one criterion had to be presence of 'dark silhouettes' or 'bright tumor islands'. RESULTS: Among 54 lesions imaged with both RCM devices, 45 were biopsy-proven BCCs. Comparison between TWP-RCM vs. HH-RCM was as follows: sensitivity (100% vs. 93%), specificity (78% for both probes), positive predictive value (96% vs. 95%), and negative predictive value (100% vs. 70%) respectively. Notably, both TWP-RCM and HH-RCM demonstrated the presence of 'dark silhouettes' or 'bright tumor islands' in all 45 BCCs. CONCLUSION: Both RCM probes demonstrate high PPV. TWP-RCM shows higher NPV, since its broader field-of-view probably allows more exhaustive search for BCC criteria. The RCM criteria threshold for BCC identification should be further tested.

Melanocytic naevi with globular and reticular dermoscopic patterns display distinct BRAF V600E expression profiles and histopathological patterns.

BACKGROUND: BRAF (v-raf murine sarcoma viral oncogene homologue B) V600E mutations have been detected with high frequency in melanocytic naevi. Few studies have stratified analyses by naevus dermoscopic pattern. OBJECTIVES: To determine the frequency of BRAF V600E expression and histopathological pattern in acquired melanocytic naevi distinguished by a globular vs. reticular dermoscopic pattern. METHODS: We retrospectively identified histologically proven melanocytic naevi with banal reticular or globular dermoscopic patterns and evaluated BRAF V600E expression using immunohistochemistry. RESULTS: BRAF V600E expression was detected in 11 of 12 globular naevi vs. four of 13 reticular naevi (91·7% vs. 30·1%, P = 0·004). A predominantly dermal growth pattern (P < 0·001) and the presence of large junctional nests (P = 0·017) were each associated with a globular dermoscopic pattern. The presence of either a predominantly dermal growth pattern or large junctional nests was found in 13 of 15 naevi positive for BRAF V600E and in two of 10 naevi negative for BRAF V600E (86·7% vs. 20%, P = 0·002). CONCLUSIONS: The frequency of BRAF V600E mutations differs in naevi distinguished by unique dermoscopic structures and microanatomical growth patterns. Globular naevi, which most often histologically correspond to a predominantly dermal growth pattern and/or the presence of large junctional nests, are significantly more likely to express BRAF V600E than reticular naevi. These preliminary results require validation, but may directly inform future studies of naevogenesis and melanoma genesis.

Towards an in vivo morphologic classification of melanocytic nevi.

BACKGROUND: Nevi are common benign neoplasms and the main diagnostic entity in the differential diagnosis of melanoma. Reflectance confocal microscopy (RCM), a novel technique for skin imaging at cellular-level magnification, has been shown to be useful for differentiating nevi from melanoma. However, systematic studies of the specific RCM features of nevi are still lacking. OBJECTIVE: To describe the characteristic RCM features of common melanocytic nevi and to correlate them with histopathology. METHODS: A total of 180 biopsy-proven nevi were imaged with RCM prior to excision. RCM images were evaluated for the overall nevus pattern and presence of specific RCM criteria. Upon histopathology, nevi were analysed for thickness using adapted Breslow depth and Clark's level grading. RESULTS: Observed RCM patterns varied according to anatomic depth of nevi. Junctional nevi were mainly characterized on RCM by a Ringed pattern, indicating a predominantly single cell proliferation of melanocytes; in contrast, the junctional component of compound nevi appeared on RCM as a Meshwork pattern, indicating a predominantly nested-proliferation. In compound nevi, the size of dermal nests was related to the thickness of nevi. Moreover, nevi extending deeper into the dermis were more likely to display a junctional component that extended laterally beyond the dermal component and appeared on RCM as either Ringed or Meshwork pattern. Intradermal nevi showed on RCM, in almost all cases, large clods. CONCLUSIONS: The possibility for in vivo histopathological classification of nevi may help in attaining a better understanding of the origin of nevi and of nevus-related melanoma risk.