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.

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.

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.