The study of nevi in children: Principles learned and implications for melanoma diagnosis

Dermoscopic monitoring of pediatric melanocytic nevi regarding pattern and diameter changes

BACKGROUND

Childhood and adolescence are dynamic period in terms of nevogenesis, and the development and growth of new melanocytic nevus are frequently observed. In this study, the aim was to examine the pattern and diameter changes seen in the follow-up of pediatric melanocytic nevus.

OBJECTIVES

To describe the pattern and diameter changes seen in the follow-up of pediatric melanocytic.

METHODS

Our study involved the assessment of 301 pediatric melanocytic nevi in 50 patients attended at the Dermatology Clinic of Istanbul Training and Research Hospital between January 2008 and 2022. The pediatric melanocytic nevi were diagnosed clinically and dermoscopically. Subsequently, we conducted video-dermoscopic monitoring of these nevi over a span of 3 months to 3 years.

RESULTS

46% of our patients were female (n = 23), with a mean age of 11.5 years. While the pattern of nevi was globular in 40% patients, the rate of globular pattern decreased to 30% in the follow-up. The basal homogeneous nevus pattern was seen in 10% patients, but was detected in 13.9% in the follow-up. Peripheral globules were observed in 19.3% of the cases, but in the follow-up, 61.1% of the globules regressed completely. Nevus excision was indicated in only 11 of 301 nevi.

STUDY LIMITATIONS

Single-center study and a small of studies available on this subject.

CONCLUSIONS

Pediatric melanocytic nevi can show dynamic changes compared to nevi in adults. In this study, growth rates, dermoscopic features, and pattern changes seen in the follow-up of melanocytic nevi were evaluated. The globular pattern was observed most frequently. The presence of peripheral globules is frequently observed in pediatric melanocytic nevi with regression during the follow-up period.

A facial lentiginous nevus with atypical clinical features in a child: The importance of in vivo reflectance confocal microscopic findings

A 14-year-old girl presented with a facial-pigmented lesion suspicious of melanoma clinically and dermoscopically. In vivo, reflectance confocal microscopy (RCM) findings excluded melanoma by revealing typical epidermal honeycomb and cobblestone patterns. Well-defined follicular contours were seen at the dermal-epidermal junction; there were no elongated, "medusa head-like" follicular protrusions or folliculotropism, which are classical findings seen in lentigo maligna. With this report, we aim to demonstrate the significance of utilizing RCM technology in difficult to diagnose lentiginous pigmented lesions.

Epidemiological characteristics and hospitalization burden analysis of pediatric inpatients with melanocytic nevi in China from 2016 to 2021: A nationwide retrospective study of 13,396 cases

BACKGROUND

Melanocytic nevi typically appear in early childhood, and their removal is a common plastic surgery procedure performed on children. However, the epidemiological characteristics and hospitalization burden of children with melanocytic nevi have rarely been described in detail.

METHODS

Medical records of pediatric inpatients with melanocytic nevi from January 1, 2016, to December 31, 2021, were collected from the Futang Research Center of Pediatric Development database in China. We then extracted and statistically analyzed the relevant information, including demographic characteristics, clinical information, hospitalization burden, and other basic information for each inpatient.

RESULTS

Among the 13,396 inpatients with melanocytic nevi, the highest number of cases was found in East China, and most patients were residents of urban areas. Most hospitalized patients consisted of boys aged 7-12 years with melanocytic nevi. Lesion sites in the buttocks and lower limbs were most common among pediatric inpatients with melanocytic nevi. Compound nevi were the most common (38.50 %) histological subtype and the rate of conversion into melanoma was 1.02 % (137 inpatients) among pediatric inpatients with melanocytic nevi. The hospitalization burden for patients varied significantly based on factors such as the age of the patients undergoing surgery, year of hospitalization, site of the lesion, histological subtype, and surgical method. In general, if the patients' age was under 1 year, lesion site was located in face, and there was a need for excision combined with tissue expander can significantly increase the treatment fees for pediatric inpatients with melanocytic nevi.

CONCLUSION

Given the increasing number and relatively large hospitalization burden among children with melanocytic nevi hospitalized in China, the government needs to pay more attention to this group and provide corresponding economic and policy support.

Improving Artificial Intelligence-Based Diagnosis on Pediatric Skin Lesions

Artificial intelligence algorithms to classify melanoma are dependent on their training data, which limits generalizability. The objective of this study was to compare the performance of an artificial intelligence model trained on a standard adult-predominant dermoscopic dataset before and after the addition of additional pediatric training images. The performances were compared using held-out adult and pediatric test sets of images. We trained two models: one (model A) on an adult-predominant dataset (37,662 images from the International Skin Imaging Collaboration) and the other (model A+P) on an additional 1,536 pediatric images. We compared performance between the two models on adult and pediatric held-out test images separately using the area under the receiver operating characteristic curve. We then used Gradient-weighted Class Activation Maps and background skin masking to understand the contributions of the lesion versus background skin to algorithm decision making. Adding images from a pediatric population with different epidemiological and visual patterns to current reference standard datasets improved algorithm performance on pediatric images without diminishing performance on adult images. This suggests a way that dermatologic artificial intelligence models can be made more generalizable. The presence of background skin was important to the pediatric-specific improvement seen between models. Our study highlights the importance of carefully curated and labeled data from diverse inputs to improve the generalizability of AI models for dermatology, in this case applied to dermoscopic images of adult and pediatric lesions to improve melanoma detection.

Domain shifts in dermoscopic skin cancer datasets: Evaluation of essential limitations for clinical translation

The limited ability of Convolutional Neural Networks to generalize to images from previously unseen domains is a major limitation, in particular, for safety-critical clinical tasks such as dermoscopic skin cancer classification. In order to translate CNN-based applications into the clinic, it is essential that they are able to adapt to domain shifts. Such new conditions can arise through the use of different image acquisition systems or varying lighting conditions. In dermoscopy, shifts can also occur as a change in patient age or occurence of rare lesion localizations (e.g. palms). These are not prominently represented in most training datasets and can therefore lead to a decrease in performance. In order to verify the generalizability of classification models in real world clinical settings it is crucial to have access to data which mimics such domain shifts. To our knowledge no dermoscopic image dataset exists where such domain shifts are properly described and quantified. We therefore grouped publicly available images from ISIC archive based on their metadata (e.g. acquisition location, lesion localization, patient age) to generate meaningful domains. To verify that these domains are in fact distinct, we used multiple quantification measures to estimate the presence and intensity of domain shifts. Additionally, we analyzed the performance on these domains with and without an unsupervised domain adaptation technique. We observed that in most of our grouped domains, domain shifts in fact exist. Based on our results, we believe these datasets to be helpful for testing the generalization capabilities of dermoscopic skin cancer classifiers.

Sun-Protective Clothing Worn Regularly during Early Childhood Reduces the Number of New Melanocytic Nevi: The North Queensland Sun-Safe Clothing Cluster Randomized Controlled Trial

Numerous pigmented moles are associated with sun exposure and melanomarisk. This cluster randomized controlled trial aimed to determine if sun-protective clothing could prevent a significant proportion of the moles developing in young children (ACTRN12617000621314; Australian New Zealand Clinical Trials Registry. Twenty-five childcare centers in Townsville (19.25° S), Australia, were matched on shade provision and socioeconomic status. One center from each pair was randomized to the intervention arm and the other to the control arm. Children at 13 intervention centers wore study garments and legionnaire hats at childcare and received sun-protective swimwear and hats for home use, while children at the 12 control centers did not. The 1–35-month-old children (334 intervention; 210 control) were examined for moles at baseline (1999–2002) and were re-examined annually for up to 4 years. Both groups were similar at baseline. Children at intervention centers acquired fewer new moles overall (median 12.5 versus 16, p = 0.02; 0.46 versus 0.68 moles/month, p = 0.001) and fewer new moles on clothing-protected skin (6 vs. 8; p = 0.021 adjusted for confounding and cluster sampling) than controls. Intervention children had 24.3% fewer new moles overall (26.5 versus 35) and 31.6% (13 versus 19) fewer moles on clothing-protected skin than controls after 3.5 years. Sunlight’s influence on nevogenesis is mitigated when children regularly wear UPF 30-50+ clothing covering half their body, implying that increased clothing cover reduces melanoma risk. Sun-protective clothing standards should mandate reporting of the percentage of garment coverage for childrenswear.

Melanoma with peripheral globules: clinical and dermoscopic features

BACKGROUND

Morphology and biology of nevi with peripheral globules are well known, while that of melanomas with peripheral globules remain unclear.

OBJECTIVE

Comparing the dermoscopic characteristics of nevi and melanomas with peripheral globules.

METHODS

A total of 401 melanocytic lesions with peripheral globules were included in this retrospective study. Dermoscopic patterns and structures, including those of the peripheral globules, were evaluated. A generalized estimating equation model with a binomial distribution dependent variable and logit link function was fitted to the dataset to identify features with the highest odds for differentiating melanoma from nevi.

RESULTS

Of the 401 lesions, 179 (44.64%) were excised, 41 (10.22%) of which were melanoma. Melanomas were most common in the lower extremities (P<0.01), with a disorganized pattern, whereas melanocytic nevi were most common on the trunk, with an organized pattern. The presence of blotches, atypical dots and globules, or atypical vessels was associated with melanomas (P<0.01).

LIMITATIONS

The retrospective design of the study may have caused an inclusion bias.

CONCLUSION

Melanocytic lesions displaying peripheral globules are at the greatest risk for melanoma if located on the lower extremity and if lesions reveal any of the following structures: blotch or atypical dots and globules or atypical vessels.

In vivo microscopy as an adjunctive tool to guide detection, diagnosis, and treatment

SIGNIFICANCE

There have been numerous academic and commercial efforts to develop high-resolution in vivo microscopes for a variety of clinical use cases, including early disease detection and surgical guidance. While many high-profile studies, commercialized products, and publications have resulted from these efforts, mainstream clinical adoption has been relatively slow other than for a few clinical applications (e.g., dermatology).

AIM

Here, our goals are threefold: (1) to introduce and motivate the need for in vivo microscopy (IVM) as an adjunctive tool for clinical detection, diagnosis, and treatment, (2) to discuss the key translational challenges facing the field, and (3) to propose best practices and recommendations to facilitate clinical adoption.

APPROACH

We will provide concrete examples from various clinical domains, such as dermatology, oral/gastrointestinal oncology, and neurosurgery, to reinforce our observations and recommendations.

RESULTS

While the incremental improvement and optimization of IVM technologies should and will continue to occur, future translational efforts would benefit from the following: (1) integrating clinical and industry partners upfront to define and maintain a compelling value proposition, (2) identifying multimodal/multiscale imaging workflows, which are necessary for success in most clinical scenarios, and (3) developing effective artificial intelligence tools for clinical decision support, tempered by a realization that complete adoption of such tools will be slow.

CONCLUSIONS

The convergence of imaging modalities, academic-industry-clinician partnerships, and new computational capabilities has the potential to catalyze rapid progress and adoption of IVM in the next few decades.

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.

A practical review of dermoscopy for pediatric dermatology part I: Melanocytic growths

The value of dermoscopy in the detection of skin cancer is well established. Less is published on the utility of dermoscopy in the evaluation of pediatric skin disease. Our review (in two parts) aims to serve as an update on pediatric dermoscopy and to provide readers with a practical application for the use of dermoscopy in pediatric dermatology clinics. In part I, we propose a dermoscopy algorithm for pediatric skin disease and melanocytic growths, and in part II, we address vascular growths, common skin infections, and inflammatory conditions for which dermoscopy is valuable.

Clinical and dermoscopic features of surgically treated melanocytic nevi: a retrospective study of 1046 cases

Background:

Compared with Caucasians, unique demographic and clinical features have been reported in Chinese patients with malignant melanoma, but similar comparative studies of melanocytic nevi (MN) are lacking. This study examined the clinical and dermoscopic features of MN in surgically treated Chinese cases.

Methods:

Clinical data and dermoscopic findings from 1046 cases of MN were collected and analyzed. Cases were treated from January 1 to December 31, 2014 at the Department of Dermatology and Venerology, Peking University First Hospital. The association between nevi location and histologic subtypes was examined with Chi-squared test and univariate logistic regression. Chi-squared test was also used to analyze the proportion of globular patterns across different body sites, and proportion of parallel furrow patterns across different histologic subtypes.

Results:

The majority of the nevi were from female patients, irrespective of location. The range of age at the time of nevi onset was from 0 (birth) to 79 years. There were 381 (36.4%, 381/1046) congenital nevi; of these 81.6% (311/381) were present at birth. Nevi appeared before 30 years of age in 83.2% (870/1046) of the cases. Median values of length growth rate in congenital and acquired MN were 2.0 and 1.6, respectively. Median values of length growth rates in four age groups (0–9, 10–19, 20–29, and ≥30 years) of congenital nevi were 2.2, 2.0, 2.4, and 2.0, respectively. In acral nevi, which often need to be differentiated from acral lentiginous melanoma, 50.2% (109/217) were junctional (odds ratio [OR]; 95% confidence interval [CI]: 91.572 [52.210–160.959], P < 0.05). Acral location was also associated with a higher likelihood of compound nevi subtype (OR [95% CI]: 14.468 [8.981–23.306], P < 0.05). The globular (59.4%, 354/596) and pseudonetwork (48.8%, 291/596) dermoscopic patterns were often seen in the head and neck region. In areas other than head and neck and acral regions, the globular pattern was the commonest pattern (34.8%, 71/204) regardless of age. Parallel furrow pattern occurred in 46.0% (87/189) of acral MN, followed by fibrillar pattern (21.7%, 41/189).

Conclusion:

Unique clinical and dermoscopic features exist in Chinese patients with MN compared with observations reported in other population.

Sequential digital dermatoscopic imaging of patients with multiple atypical nevi

Patients with multiple atypical nevi are at higher risk of developing melanoma. Among different techniques, sequential digital dermatoscopic imaging (SDDI) is a state-of-the art method to enhance diagnostic accuracy in evaluating pigmented skin lesions. It relies on analyzing digital dermatoscopic images of a lesion over time to find specific dynamic criteria inferring biologic behavior. SDDI can reduce the number of necessary excisions and finds melanomas in an early—and potentially curable—stage, but precautions in selecting patients and lesions have to be met to reach those goals.

Patients with Spitz naevi in the Greek population: Epidemiologic, Clinical and Histopathological characteristics

BACKGROUND

Spitz naevi may present with clinical and histopathological atypical features that do not affect patient prognosis but may become worrisome for patients ≥40 years presenting with newly appearing SN.

OBJECTIVE

Patient characteristics and sun behaviour patterns were investigated in correlation with age. SN characteristics and histopathological attributes were also investigated in correlation with age.

METHODS

Patients with histopathologically confirmed diagnosis of SN were invited for a clinical examination. Data such as skin type, number of banal/atypical naevi, sun exposure patterns and personal/family history were collected. Histopathology preparations were re-examined by two different histopathologists, and characteristics were collected based on a prespecified checklist. Patients were afterwards followed up every 6 months.

RESULTS

A total of 110 patients with SN were identified and assigned to three age groups. The most common area of presentation was the trunk, for the ≥40 years age group, and the limbs for the other age groups. Patients ≥40 years had a higher possibility of presenting with a naevus count ≥50 and at least one atypical naevus compared to the other age groups. Patients ≥40 years presented more commonly with a history of painful sunburn (100%) before the appearance of the SN, used less sunscreen, had higher sun exposure times and more clinical signs of solar skin damage compared to the other age groups. Finally, patients ≥40 years presented more commonly with signs of histopathological atypia such as the presence of mitoses, cellular atypia and prominent nucleolus.

CONCLUSION

Patients ≥40 were more likely to report a history of longer sun exposure times, of never using a sunscreen and of having a history of painful sunburn. However, the importance of this observation remains to be elucidated as these patients also presented more commonly with lesions located on non-sun-exposed areas (trunk) and higher naevus/atypical naevus counts.

Results of the 2016 International Skin Imaging Collaboration International Symposium on Biomedical Imaging challenge: Comparison of the accuracy of computer algorithms to dermatologists for the diagnosis of melanoma from dermoscopic images

BACKGROUND

Computer vision may aid in melanoma detection.

OBJECTIVE

We sought to compare melanoma diagnostic accuracy of computer algorithms to dermatologists using dermoscopic images.

METHODS

We conducted a cross-sectional study using 100 randomly selected dermoscopic images (50 melanomas, 44 nevi, and 6 lentigines) from an international computer vision melanoma challenge dataset (n = 379), along with individual algorithm results from 25 teams. We used 5 methods (nonlearned and machine learning) to combine individual automated predictions into "fusion" algorithms. In a companion study, 8 dermatologists classified the lesions in the 100 images as either benign or malignant.

RESULTS

The average sensitivity and specificity of dermatologists in classification was 82% and 59%. At 82% sensitivity, dermatologist specificity was similar to the top challenge algorithm (59% vs. 62%, P = .68) but lower than the best-performing fusion algorithm (59% vs. 76%, P = .02). Receiver operating characteristic area of the top fusion algorithm was greater than the mean receiver operating characteristic area of dermatologists (0.86 vs. 0.71, P = .001).

LIMITATIONS

The dataset lacked the full spectrum of skin lesions encountered in clinical practice, particularly banal lesions. Readers and algorithms were not provided clinical data (eg, age or lesion history/symptoms). Results obtained using our study design cannot be extrapolated to clinical practice.

CONCLUSION

Deep learning computer vision systems classified melanoma dermoscopy images with accuracy that exceeded some but not all dermatologists.

Evolution of Spitz Nevi

BACKGROUND/OBJECTIVES

Spitz nevi are melanocytic lesions with clinical, dermoscopic, and histopathologic presentations that may resemble those of melanoma. The evolution of Spitz nevi is a well-known feature. The objectives of this study were to investigate the clinical and dermoscopic features of Spitz nevi and define their evolution.

METHODS

A retrospective observational study was performed and 70 Spitz nevi were analyzed using clinical and dermoscopic examination.

RESULTS

Seventy patients were included in the study. The most common dermoscopic pattern was globular (n = 35 [50%]) followed by starburst (n = 24 [34.3%]), reticular (n = 8 [11.4%]), and homogeneous (n = 3 [4.3%]). Follow-up data were available for 27 of 70 patients. Of these, 21 demonstrated evolution on the follow-up images. A stable pattern (no evolution) was noted in 6 of 27 lesions. The patients who exhibited evolution were younger on average than the stable group (p = 0.04).

CONCLUSION

Based on our study, the most common biologic behavior for Spitz nevi is evolution. Although no significant differences were observed in other clinical features, the inverse relationship between evolution and age is important to consider when attempting to differentiate Spitz nevus from melanoma.