3D Whole-body skin imaging for automated melanoma detection.

BACKGROUND: Existing artificial intelligence for melanoma detection has relied on analysing images of lesions of clinical interest, which may lead to missed melanomas. Tools analysing the entire skin surface are lacking. OBJECTIVES: To determine if melanoma can be distinguished from other skin lesions using data from automated analysis of 3D-images. METHODS: Single-centre, retrospective, observational convenience sample of patients diagnosed with melanoma at a tertiary care cancer hospital. Eligible participants were those with a whole-body 3D-image captured within 90 days prior to the diagnostic skin biopsy. 3D-images were obtained as standard of care using VECTRA WB360 Whole Body 3-dimensional Imaging System (Canfield Scientific). Automated data from image processing (i.e. lesion size, colour, border) for all eligible participants were exported from VECTRA DermaGraphix research software for analysis. The main outcome was the area under the receiver operating characteristic curve (AUC). RESULTS: A total of 35 patients contributed 23,538 automatically identified skin lesions >2 mm in largest diameter (102-3021 lesions per participant). All were White patients and 23 (66%) were males. The median (range) age was 64 years (26-89). There were 49 lesions of melanoma and 22,489 lesions that were not melanoma. The AUC for the prediction model was 0.94 (95% CI: 0.92-0.96). Considering all lesions in a patient-level analysis, 14 (28%) melanoma lesions had the highest predicted score or were in the 99th percentile among all lesions for an individual patient. CONCLUSIONS: In this proof-of-concept pilot study, we demonstrated that automated analysis of whole-body 3D-images using simple image processing techniques can discriminate melanoma from other skin lesions with high accuracy. Further studies with larger, higher quality, and more representative 3D-imaging datasets would be needed to improve and validate these results.

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.

Sun Protection Behavior Following Skin Cancer Resection and Reconstruction.

Increased exposure to ultraviolet radiation (UVR) is associated with an increased risk of nonmelanoma skin cancer. Cutaneous surgery can be negatively influenced by UVR, causing delayed wound healing, hyperpigmentation of the scar, and an increased incidence of additional skin cancers. By changing sun protection behavior, these risks can be limited. Therefore, this study evaluates changes in patients' sun protective behavior after Mohs micrographic surgery (MMS). Patients undergoing MMS between December 2017 and November 2019 were included. Patients were asked to complete the FACE-Q Skin Cancer - Sun Protection Behavior checklist before and 3 months and 1 year post-surgery. A total of 125 patients completed the pre-operative and 3-months post-operative checklists, and 89 (71.2%) completed the 1-year post-operative checklist. Reported sun protective behaviors increased post-surgery at all time points (p < 0.001). Patients with a prior history of facial skin cancer demonstrated a larger increase in sun protection behaviors after surgery than patients without a history of facial skin cancer (p = 0.04). Patients with defects located on the ear or scalp demonstrated a lesser increase in sun protection behaviors than patients with defects located in more conspicuous areas as the face (p = 0.02). Our study demonstrates a change in sun protection behavior, with an increase in sun protection behavior over time in patients after MMS. However, more improvement is possible. Targeted counseling can increase sun protection behavior in patients without a history of facial skin cancer and patients with skin cancer located on the ears or scalp.

Association between the dermoscopic morphology of peripheral globules and melanocytic lesion diagnosis.

BACKGROUND: The presence of peripheral globules is associated with enlarging melanocytic lesions; however, there are numerous patterns of peripheral globules distribution and it remains unknown whether specific patterns can help differentiate enlarging naevi from melanoma. OBJECTIVE: To investigate whether morphological differences exist between the peripheral globules seen in different subsets of naevi and in melanoma. METHODS: A cross-sectional study of clinical notes that mentioned peripheral globules, in addition to all melanoma images with peripheral globules on the International Skin Imaging Collaboration archive. Dermoscopic images were reviewed and annotated. Associations between diagnosis and categorical features were measured with odds ratios. Non-parametric tests were used for continuous factors. RESULTS: 184 lesions with peripheral globules from our clinic were included in the analysis; only 6 of these proved to be melanoma. 109 melanomas with peripheral globules from the International Skin Imaging Collaboration archive were added to the analysis. Melanomas were more common on the extremities and among older individuals. Melanomas were more likely to display atypical, tiered and/or focal peripheral globules. Only 5% of melanomas lacked dermoscopic melanoma-specific structures compared to 48% of naevi. CONCLUSIONS: Melanocytic lesions with atypical or asymmetrically distributed peripheral globules, especially when located on the extremities, should raise suspicion for malignancy. Melanocytic lesions with typical and symmetrically distributed peripheral globules, and with no other concerning dermoscopic features, are unlikely to be malignant.

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.

'Inverse association between the total naevus count and melanoma thickness'.

BACKGROUND: Individuals with a high total naevus count (TNC) are at a higher risk to develop melanoma, and screening efforts have been largely focused on this group. However, some studies suggest that melanomas of patients with many nevi are thinner than those of patients with few nevi. Additionally, nodular melanoma has been associated with individuals with a low naevus count. OBJECTIVE: To investigate the association between TNC and melanoma Breslow thickness. METHODS: A two-centre retrospective study from 1 January 2016 to 1 January 2018. This included three hundred and twenty-six consecutive melanoma patients from two tertiary melanoma centres. The mean age at presentation was 58.3 years (SD = 15.9), and the majority (54.9%, N = 179) were men. Incidence of new in situ and invasive melanomas and correlation with TNC were measured. RESULTS: The mean total naevus count for patients presenting with in situ melanoma was 57.2 (range 4-178), while for patients presenting with invasive disease was 31.5 (P = 0.01). In situ disease was associated with a higher TNC across all ages. For invasive melanoma, a positive association between age and Breslow thickness was observed, while TNC was inversely associated with Breslow thickness. Each additional naevus accounted for a 4% decreased likelihood that the subject had invasive disease. CONCLUSION: Patients with a higher naevus count had thinner melanomas and more melanomas in situ, independent of age and sex.

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.

Dermoscopic features and patterns of poromas: a multicentre observational case-control study conducted by the International Dermoscopy Society.

BACKGROUND: Poromas are benign cutaneous sweat gland tumours that are challenging to identify. The dermoscopic features of poromas are not well characterized. OBJECTIVE: To determine the clinical-dermoscopic features of poromas. METHODS: Cross-sectional, observational study of 113 poromas and 106 matched control lesions from 16 contributors and eight countries. Blinded reviewers evaluated the clinical and dermoscopic features present in each clinical and dermoscopic image. RESULTS: Poromas were most commonly non-pigmented (85.8%), papules (35.4%) and located on non-acral sites (65.5%). In multivariate analysis, dermoscopic features associated with poroma included white interlacing areas around vessels (OR: 7.9, 95% CI: 1.9-32.5, P = 0.004), yellow structureless areas (OR: 2.5, 95% CI: 1.1-6.0, P = 0.04), milky-red globules (OR: 3.9, 95% CI: 1.4-11.1, P = 0.01) and poorly visualized vessels (OR: 33.3, 95% CI: 1.9-586.5, P = 0.02). The presence of branched vessels with rounded endings was positively associated with poromas but did not reach statistical significance (OR: 2.4, 95% CI: 0.8-6.5, P = 0.10). The presence of any of these five features was associated with a sensitivity and specificity of 62.8% and 82.0%, respectively. CONCLUSION: We identified dermoscopic features that are specific to the diagnosis of poroma. Overall, however, the prevalence of these features was low. Significant clinical and dermoscopic variability is a hallmark of these uncommon tumours, which are most prevalent on non-acral sites.

A Clinical Aid for Detecting Skin Cancer: The Triage Amalgamated Dermoscopic Algorithm (TADA).

PURPOSE: Family physicians (FPs) frequently evaluate skin lesions but may not have the necessary training to accurately and confidently identify lesions that require skin biopsy or specialist referral. We evaluated the diagnostic performance of a new, simplified dermoscopy algorithm for skin cancer detection. METHODS: In this cross-sectional, observation study, attendees of a dermoscopy course evaluated 50 polarized dermoscopy images of skin lesions (27 malignant and 23 benign) using the Triage Amalgamated Dermoscopic Algorithm (TADA). The dermoscopic criteria of TADA include architectural disorder (ie, disorganized or asymmetric distribution of colors and/or structures), starburst pattern, blue-black or gray color, white structures, negative network, ulcer, and vessels. The study occurred after 1 day of basic dermoscopy training. Clinical information related to palpation (ie, firm, dimpling) was provided when relevant. RESULTS: Of 200 course attendees, 120 (60%) participated in the study. Participants included 64 (53.3%) dermatologists and 41 (34.2%) primary care physicians, 19 (46.3%) of whom were FPs. Fifty-two (43%) individuals had no previous dermoscopy training. Overall, the sensitivity and specificity of TADA for malignant skin lesions was 94.8% and 72.3%, respectively. Previous dermoscopy training and years of dermoscopy experience were not associated with diagnostic sensitivity (P = .13 and P = .05, respectively) or specificity (P = .36 and P = .21, respectively). Specialty type was not associated with sensitivity (P = .37) but dermatologists had a higher specificity than nondermatologists (79% v. 72%, P = .008). CONCLUSIONS: After basic instruction, TADA may be a useful dermoscopy algorithm for FPs who examine skin lesions as it has a high sensitivity for detecting skin cancer.

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.

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.

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.

Dermoscopy of acral melanoma: a multicenter study on behalf of the international dermoscopy society.

BACKGROUND: Most studies on dermoscopy of acral lesions were conducted in Asian populations. In this study, we analyzed these features in a predominantly Caucasian population. OBJECTIVE: Estimate the prevalence of dermoscopic features in acral lesions, and assess their level of agreement between observers. METHODS: In this retrospective multicenter study, 167 acral lesions (66 melanomas) were evaluated for 13 dermoscopic patterns by 26 physicians, via a secured Internet platform. RESULTS: Parallel furrow pattern, bizarre pattern, and diffuse pigmentation with variable shades of brown had the highest prevalence. The agreement for lesion patterns between physicians was variable. Agreement was dependent on the level of diagnostic difficulty. CONCLUSION: Lesions with a diameter >1 cm were more likely to be melanoma. We found as well that a benign pattern can be seen in parts of melanomas. For this reason one should evaluate an acral lesion for the presence of malignant patterns first.

Clinical and dermoscopic characteristics of new naevi in adults: results from a cohort study.

BACKGROUND: Naevogenesis is a process known to occur throughout life. To date, investigators have made conclusions about new naevi in adults based on results of cross-sectional studies. OBJECTIVES: To determine the incidence of new naevus development in adults and to describe the dermoscopic morphology of new naevi. METHODS: A cohort of 182 patients seen at the outpatient dermatology clinic at Memorial Sloan-Kettering Cancer Center between 2000 and 2009 was evaluated with baseline total body photographs. The patients were aged 17 years or older and had presented for routine follow-up surveillance examination at least 3 months after baseline total body photographs. The number of new naevi and the dermoscopic morphology of these naevi were recorded. RESULTS: Of the 182 patients evaluated, 50 (27%) developed at least one new naevus during follow-up. The incidence of new naevi was 202 per 1000 person-years of follow-up. The most common types of naevi were reticular (47·1%), followed by the homogeneous (22·1%) and complex (reticuloglobular) patterns (15·4%). CONCLUSIONS: Our results provide support for the theory that there are two distinct pathways of naevogenesis, a dynamic process occurring throughout life. This study demonstrates that the predominant dermoscopic morphology of newly acquired naevi in adults is reticular.

One-year follow-up of dermoscopy education on the ability of medical students to detect skin cancer.

BACKGROUND: Learning skin cancer detection skills is important, yet many medical schools lack a standardized skin cancer examination (SCE) curriculum. OBJECTIVE: To determine medical students' skills in discriminating benign from malignant skin lesions on a 10-item image-based test one year after receiving a SCE intervention. METHODS: Cohort 1 received SCE teaching only. Cohort 2 received SCE teaching with dermoscopy tutorial, and a dermatoscope. The same test was given to assess students post-intervention and one year later. RESULTS: 43% (n = 145) and 38% (n = 143) of cohorts 1 and 2, respectively, participated one year later. Both cohorts improved or maintained their scores to correctly classify all lesions from post-intervention to one-year follow-up. After one year, cohort 2 maintained higher scores for successful identification of both benign and malignant lesions as compared to cohort 1. CONCLUSION: Medical students receiving a SCE intervention can improve their diagnostic skills after one year, especially with the aid of dermoscopy.

Changes observed in slow-growing melanomas during long-term dermoscopic monitoring.

BACKGROUND: Melanomas vary in growth rate from rapidly developing nodular melanomas to slow-growing melanomas (SGM) that hardly change over years. OBJECTIVES: To evaluate longitudinal changes in dermoscopic findings of SGM. METHODS: We retrospectively analysed a dermoscopic image dataset from 15 pigmented lesion clinics, of SGM that were followed sequentially by digital dermoscopy for at least 1 year. We evaluated baseline and follow-up images for changes in global pattern, organization, colours, structure and size. RESULTS: Our series consisted of 92 SGM. On follow-up, these melanomas developed the following dermoscopic findings: more homogeneous and less reticular global dermoscopic pattern; more frequent disorganization of pattern (baseline, 67% vs. follow-up, 79%); decreased prominence of light brown colour, increased prominence of dark brown colour, and increased frequency of the colours red, white, grey, blue and black (baseline: 29%, 3%, 18%, 6% and 33% vs. follow-up: 41%, 10%, 31%, 13% and 45%, respectively); decrease in prominence of dermoscopic structure of pigmented network, with a concomitant increase in prominence of structureless areas; and increased prominence or new appearance of melanoma-specific dermoscopic structures, including negative network, blue-white structures and blotches. The majority of lesions (75%) remained the same size or grew by < 2 mm in diameter. An increase in lesion size was associated with change in the total number of colours and structures (χ(2) = 14·3, P = 0·027) at follow-up. CONCLUSIONS: While their diameter changed minimally over time, most SGM became more disorganized, revealed loss of network in favour of structureless areas, and developed new colours.

White shiny structures: dermoscopic features revealed under polarized light.

BACKGROUND: White shiny structures, including white shiny lines, white shiny areas and rosettes, are features only observed under polarized dermoscopy (PD). OBJECTIVE: To evaluate the prevalence of the varied morphologies of white shiny structures in melanoma, basal cell carcinoma (BCC), squamous cell carcinoma (SCC), actinic keratosis (AK) and lichen planus-like keratosis (LPLK). METHODS: Retrospective study using dermoscopic images of biopsy-proven melanoma, BCC, SCC, AK and LPLK. RESULTS: A total of 538 lesions were assessed under PD. One or more types of white shiny structures were observed in 38.7% of study lesions (208/538). BCCs were significantly more likely to display a combination of white shiny areas and white shiny lines (short lines and/or ill-defined strands) (31.9%; 61/191) than any other lesions (P<0.001). BCC were more likely than other lesions to have white shiny lines distributed without any organized pattern (P<0.001). Lines in melanoma were significantly more likely than other lesion types to be oriented orthogonally (P<0.001). When white shiny lines were present, melanomas were significantly more likely than other lesions to exhibit short discrete white lines (P<0.001). Rosettes were significantly more likely to be observed in actinic tumours than other lesions (P<0.001). CONCLUSION: The presence of white shiny lines of any length accompanied by white shiny areas is most suggestive of a diagnosis of BCC (P<0.001). Melanomas are more likely to display short white shiny lines in an orthogonal distribution (P<0.001) and without white shiny areas. Actinic tumours are most likely to exhibit rosettes (P<0.001).