Dermoscopic Nevus Patterns Associated with Melanoma Patients

<b><i>Background:</i></b> The quantitative and qualitative presence of melanocytic nevi is considered a significant risk factor for melanoma. Little is known whether patients showing any of the recognized global dermoscopic nevus patterns might also be considered at increased risk for the disease. <b><i>Objectives:</i></b> We aimed to investigate the frequency of global dermoscopic patterns of common nevi among melanoma patients and compare them to controls, as well as the dermoscopic patterns of atypical nevi between the groups. <b><i>Methods:</i></b> We included consecutive melanoma patients and age- and sex-matched controls who presented to our Department with at least 10 melanocytic nevi. Total body examination was performed, and all nevi had their dermoscopic pattern described. Global dermoscopic patterns of nevi were compared between groups, as well as atypical nevus patterns. Finally, nevus patterns were stratified by their location and also compared between groups. <b><i>Results:</i></b> We included 120 melanoma patients and 120 controls. Melanoma patients presented a larger number of common (<i>p</i> = 0.002) and atypical melanocytic nevi (<i>p</i> &#x3c; 0.001) and more variability of dermoscopic nevus patterns (<i>p</i> &#x3c; 0.001). No difference in the global dermatoscopic pattern of common nevi was observed between groups. The complex pattern of atypical nevi was associated with melanoma (OR = 2.87). Melanoma patients also showed more common nevi with a reticular pattern on the back (<i>p</i> = 0.014) and lower limbs (<i>p</i> = 0.041) as well as atypical nevi on the back with reticular pattern (<i>p</i> = 0.01), with reticular-homogeneous pattern (<i>p</i> = 0.001), and with reticular-globular pattern (<i>p</i> = 0.048) than controls. Nevi with multifocal pigmentation were also more frequent among melanoma patients (OR = 2.61). <b><i>Conclusion:</i></b> Melanoma patients tend to present a higher number of common reticular nevi on the back and lower limbs, as well as atypical nevi with a complex pattern, especially reticular, reticular-homogeneous, and reticular-globular on the back.

Difference in Sun Exposure Habits Between Individuals with High and Low Risk of Skin Cancer

Background: Skin cancer incidence is rapidly increasing. The main risk factor, sun exposure, can be modified. Informational campaigns can be effective in raising skin cancer awareness and target the high-risk population. Still, sun exposure habits in people at high risk of skin cancer are not well-known. Objective: To investigate if and how sun exposure habits differ between low-risk and high-risk individuals. Methods: During the Swedish Euromelanoma campaign of 2018, questionnaires were collected containing information regarding sun exposure habits and risk factors for skin cancer. Data on 4,141 participants was used to investigate the association between risk factors and sun exposure habits. Results: A fair skin type and a previous history of skin cancer were significantly associated with enhanced sun protective behavior. Family history of skin cancer, childhood sunburns and the presence of large/atypical nevi had no effect on sun exposure habits. Going on sunny holidays were particularly unaffected by being at high risk of skin cancer. Conclusion: Individuals at high risk of developing skin cancer showed suboptimal sun exposure habits and harmful traveling behaviors. We suggest that future skin cancer campaigns inform on accurate sun protection behavior during sunny holidays and associated risk factors. Risk factors such as childhood sunburns, numerous common and large/atypical nevi, as well as family history of skin cancer seem to be less recognized by the population.

Prevalence of nevi, atypical nevi, and lentigines in relation to tobacco smoking

Background Melanocytic nevi have a complex evolution influenced by several endogenous and exogenous factors and are known risk factors for malignant melanoma. Interestingly, tobacco use seems to be inversely associated with melanoma risk. However, the association between tobacco use and nevi and lentigines has not yet been evaluated. Methods We investigated the prevalence of nevi, atypical nevi, and lentigines in relation to tobacco smoking in a cohort of 59 smokers and 60 age- and sex-matched nonsmokers, using a questionnaire and performing a total body skin examination by experts. Results No significant differences were detected between smokers and nonsmokers in the numbers of nevi, atypical nevi, and lentigines in sun-exposed areas (p = 0.966, 0.326, and 0.241, respectively) and in non-sun-exposed areas (p = 0.095, 0.351, and 0.546, respectively). Conclusion Our results revealed no significant differences in the prevalence of nevi, atypical nevi, and lentigines between smokers and nonsmokers in sun-exposed and non-sun-exposed areas.

A patient-centric dataset of images and metadata for identifying melanomas using clinical context

Prior skin image datasets have not addressed patient-level information obtained from multiple skin lesions from the same patient. Though artificial intelligence classification algorithms have achieved expert-level performance in controlled studies examining single images, in practice dermatologists base their judgment holistically from multiple lesions on the same patient. The 2020 SIIM-ISIC Melanoma Classification challenge dataset described herein was constructed to address this discrepancy between prior challenges and clinical practice, providing for each image in the dataset an identifier allowing lesions from the same patient to be mapped to one another. This patient-level contextual information is frequently used by clinicians to diagnose melanoma and is especially useful in ruling out false positives in patients with many atypical nevi. The dataset represents 2,056 patients (20.8% with at least one melanoma, 79.2% with zero melanomas) from three continents with an average of 16 lesions per patient, consisting of 33,126 dermoscopic images and 584 (1.8%) histopathologically confirmed melanomas compared with benign melanoma mimickers.