Dermoscopic features of combined melanocytic nevi

Combined WNT-activated deep-penetrating/plexiform melanocytoma: insights into clinicopathological and molecular characterization

BACKGROUND

A combined deep-penetrating tumour redefined as WNT-activated deep-penetrating/plexiform melanocytoma (DPM), may pose challenging clinical and histological diagnoses.

OBJECTIVES

To review the clinicopathological characteristics of combined DPMs and characterize the molecular profile of atypical and malignant forms.

METHODS

The study included 51 patients with combined DPMs diagnosed at the Hospital Clinic of Barcelona and the University of Florence between 2012 and 2020. Clinical data, dermoscopy images (when available) and histological characteristics were reviewed. Immunohistochemistry for β-catenin, LEF1, HMB45, Ki67, p16 and PRAME (preferentially expressed antigen in melanoma) was performed. Atypical forms underwent next-generation sequencing (NGS) panel analysis, including driver genes implicated in DPMs, TERT-promoter (p) mutations and the investigation of the 9p21 locus via fluorescence in situ hybridization.

RESULTS

Among the 51 patients (32 females and 19 males, age range 4-74 years), 68% with available clinical data (15/22) were initially suspected of having melanoma. Except for one patient, complete excision resulted in no recurrences or metastases. One patient who had an incompletely excised combined DPM developed a lymph node melanoma metastasis 10 years later. In the 51 patients, 10 samples (20%) showed atypical histological features; 7 (14%) exhibited a significant loss of p16 expression; and 2 (4%) showed a high-proliferative index (Ki67 over 5%). NGS analysis in 11 patients revealed a double mutation BRAFV600E and exon 3 CTNNB1; no TERTp mutations were detected.

CONCLUSIONS

Clinical suspicion of melanoma is common in combined DPMs, but malignant progression is infrequent in tumours lacking high-grade atypia or proliferation. These findings are congruent with the consideration of these lesions as intermediate-grade tumours or melanocytomas.

Spitz Nevus with Features of Clark Nevus, So-Called SPARK Nevus: Case Series Presentation with Emphasis on Cytological and Histological Features

Background: SPARK nevus represents a little-known and characterized entity, with few case series available in the literature. Methods and results: we present a case series of 12 patients (6 F and 6 M) between January 2005 and December 2020 and conduct a review of the current literature. Ten articles were selected on the basis of the adopted inclusion criteria and the PRISMA guidelines. Conclusions: The definition of histopathological and dermoscopic criteria are important to allow for an agreement to be reached among dermopathologists, and for the development of a consensus on higher case studies. To our knowledge, there are not many case series in the literature, and ours is part of the attempt to increase the knowledge of an entity that remains little-known and characterized.

Dermatoscopy of combined blue nevi: a multicentre study of the International Dermoscopy Society

BACKGROUND

Combined blue nevi (CBN) may mimic melanoma and are relatively often biopsied for diagnostic reasons.

OBJECTIVE

To better characterize CBN and to compare it with melanoma.

METHODS

We collected clinical and dermatoscopic images of 111 histologically confirmed CBN and contrasted their dermatoscopic characteristics with 132 partly blue coloured melanomas. Furthermore, we compared the accuracy of human experts using pattern analysis with a computer algorithm based on deep learning.

RESULTS

Combined blue nevi are usually flat or slightly elevated and, in comparison with melanoma, more frequent on the head and neck. Dermatoscopically, they are typified by a blue structureless part in combination with either brown clods (n = 52, 46.8%), lines (n = 28, 25.2%) or skin-coloured or brown structureless areas (n = 31, 27.9%). In contrast with melanoma, the blue part of CBN is more often well defined (18.9% vs. 4.5%, P < 0.001) and more often located in the centre (22.5% vs. 5.3%, P < 0.001). Melanomas are more often chaotic (OR: 28.7, 95% CI: 14.8-55.7, P < 0.001), have at least one melanoma clue (OR: 10.8, 95% CI: 5.2-22.2 P < 0.001) in particular white lines (OR: 37.1, 95% CI: 13.4-102.9, P < 0.001). Using simplified pattern analysis (chaos and clues), two raters reached sensitivities of 93.9% (95% CI: 88.4-97.3%) and 92.4% (95% CI: 86.5-96.3%) at corresponding specificities of 59.5% (95% CI: 49.7-68.7%) and 65.8% (95% CI: 56.2-74.5%). The human accuracy with pattern analysis was on par with a state-of-the-art computer algorithm based on deep learning that achieved an area under the curve of (0.92, 95% CI: 0.87-0.96) and a specificity of 85.3% (95% CI: 76.5-91.7%) at a given sensitivity of 83.6% (95% CI: 72.5-91.5%).

CONCLUSION

CBN usually lack melanoma clues, in particular white lines. The accuracy of pattern analysis for combined nevi is acceptable, and histopathologic confirmation may not be necessary in exemplary cases.

Dermatoscopic Features of Combined nevus – a Case Report

Combined nevi (CN), a rare nevus type represent a category of so-called compound tumors. Determined by the presence of two or more different nevus in one biopsy specimen, CN commonly show variable clinical and dermatoscopic features. Therefore, CN could be a diagnostic challenge. We present a 7-year-old Caucasian girl with a pigmented lesion on the arm of no specified duration. Clinical examination showed sharply demarcated pigmented papule. Dermatoscopy revealed a nonchaotic lesion with structureless well defined, minimally eccentric blue area, structureless brown area and brown clods in a symmetric fashion, no vessels and no other clues for melanoma. Histopathology showed a compound common melanocytic nevus, blue nevus in the centre of the lesion with no signs of atypia. Up to now, only 25 cases of CN with dermatoscopic description have been published, withno precise dermatoscopic features established yet. Therefore, studies with larger number of cases are needed for the final conclusions.

A Case Report on the Dermoscopic Features of Spark's Nevus

Spark's nevus is a compound word composed of Spitz nevus and Clark's nevus. It is one of the combined melanocytic nevi which is more common in female and usually presents as a sharp circumscribed hyperpigmented macule on the lower extremities. On histopathologic findings, both cytologic features of Spitz nevus characterized as large spindle or epithelioid melanocytes containing large nuclei with abundant cytoplasm, and architecture of Clark's nevus characterized as elongation of rete ridges, bridging of the nests, concentric and lamellar fibrosis can be seen. A 24-year-old female presented with an asymptomatic, solitary, dark-brown-colored papule surrounded by brownish patch that looked similar to dysplastic nevus or malignant melanoma on the buttock. On dermoscopic examination, it showed brown-to-black globules, diffuse homogenous pigmentation with blue-white structures, and a surrounding brownish reticular pattern that faded away. On histopathologic findings, overall asymmetrical structure, epithelioid large melanocytes containing large nuclei with abundant cytoplasm, and Kamino body were seen in the central portion. Also, lentiginous hyperplasia, bridging of the nests composed of melanocytes containing foamy cytoplasm, concentric and lamellar fibrosis along with the elongation of rete ridge, and perivascular lymphocytic infiltration were seen in the peripheral portion. The diagnosis of Spark's nevus was made. Following its definition, this combined nevus is diagnosed histopathologically, but the clinicodermoscopic features have not been well described. Herein, we report a case of Spark's nevus in which dermoscopy was helpful for differentiating it from malignant melanoma.

Diagnostic performance of a deep learning convolutional neural network in the differentiation of combined naevi and melanomas

BACKGROUND

Deep learning convolutional neural networks (CNN) may assist physicians in the diagnosis of melanoma. The capacity of a CNN to differentiate melanomas from combined naevi, the latter representing well-known melanoma simulators, has not been investigated.

OBJECTIVE

To assess the diagnostic performance of a CNN when used to differentiate melanomas from combined naevi in comparison with dermatologists.

METHODS

In this study, a CNN with regulatory approval for the European market (Moleanalyzer-Pro, FotoFinder Systems GmbH, Bad Birnbach, Germany) was used. We attained a dichotomous classification (benign, malignant) in dermoscopic images of 36 combined naevi and 36 melanomas with a mean Breslow thickness of 1.3 mm. Primary outcome measures were the CNN's sensitivity, specificity and the diagnostic odds ratio (DOR) in comparison with 11 dermatologists with different levels of experience.

RESULTS

The CNN revealed a sensitivity, specificity and DOR of 97.1% (95% CI [82.7-99.6]), 78.8% (95% CI [62.8-89.1.3]) and 34 (95% CI [4.8-239]), respectively. Dermatologists showed a lower mean sensitivity, specificity and DOR of 90.6% (95% CI [84.1-94.7]; P = 0.092), 71.0% (95% CI [62.6-78.1]; P = 0.256) and 24 (95% CI [11.6-48.4]; P = 0.1114). Under the assumption that dermatologists use the CNN to verify their (initial) melanoma diagnosis, dermatologists achieve an increased specificity of 90.3% (95% CI [79.8-95.6]) at an almost unchanged sensitivity. The largest benefit was observed in 'beginners', who performed worst without CNN verification (DOR = 12) but best with CNN verification (DOR = 98).

CONCLUSION

The tested CNN more accurately classified combined naevi and melanomas in comparison with trained dermatologists. Their diagnostic performance could be improved if the CNN was used to confirm/overrule an initial melanoma diagnosis. Application of a CNN may therefore be of benefit to clinicians.

Differentiation of combined nevi and melanomas: Case-control study with comparative analysis of dermoscopic features

BACKGROUND AND OBJECTIVES

Combined nevi (CN) show two or more components of major nevus subtypes and simulate melanomas. We investigated a panel of dermoscopic features and three dermoscopic algorithms for differentiating CN from melanomas.

PATIENTS AND METHODS

Retrospective, blinded case-control study using dermoscopic images of 36 CN and 36 melanoma controls. Twenty-one dermoscopic features validated for the diagnosis of melanocytic lesions, the number of colors, and three dermoscopic algorithms were investigated (ABCD rule of dermoscopy, Menzies scoring method, 7-point checklist).

RESULTS

Five of seven features indicative of nevi were observed significantly more frequently in CN than in melanomas (all p < 0.05) and two were exclusively found in CN. Eleven out of 14 features indicative of melanomas were observed significantly more frequently in melanomas than in CN (all p < 0.03) and five were exclusively found in melanomas. The mean (± SD) number of colors in CN was lower than in melanomas (2.1 ± 0.6 versus 3.4 ± 0.7; p < 0.001). Among tested algorithms the ABCD rule of dermoscopy performed best (sensitivity 91.7 %, specificity 77.8 %).

CONCLUSIONS

The ABCD rule of dermoscopy differentiated CN from melanomas most efficiently. Additional knowledge of dermoscopic features to be expected exclusively in either CN or melanomas should help dermatologists to make a correct clinical diagnosis.

Dermoscopy Case of the Month Combined Nevus - a Case Report

Combined nevi are melanocytic lesions composed of two or more distinct types of melanocytic populations within the same lesion. Different types of combined nevi may form bizarrely shaped, multicolored skin lesions, making them one of the greatest melanoma mimickers. We report a 48-year-old female patient with suspicious skin lesion in the left lumbar region. Clinically, there was an oval, slightly asymmetrical lesion measuring 6 x 4 mm, showing multiple colors and shades of brown and black. A dermoscopic examination revealed a brown-bluish coloration in the right part of the lesion, while a fine pigment network with perifollicular halo was found in the left part of the lesion, suggesting the diagnosis of a combined nevus. Histological examination showed a poorly circumscribed proliferation of dendritic melanocytes in the superficial and deep dermis and proliferation of melanocytes in the dermoepidermal junction. A surgical excision of the tumor was performed, in order to confirm the dermoscopic findings. In conclusion, dermoscopy is useful in differentiating combined nevi from other melanocytic lesions.

Optimal management of common acquired melanocytic nevi (moles): current perspectives

Although common acquired melanocytic nevi are largely benign, they are probably one of the most common indications for cosmetic surgery encountered by dermatologists. With recent advances, noninvasive tools can largely determine the potential for malignancy, although they cannot supplant histology. Although surgical shave excision with its myriad modifications has been in vogue for decades, the lack of an adequate histological sample, the largely blind nature of the procedure, and the possibility of recurrence are persisting issues. Pigment-specific lasers were initially used in the Q-switched mode, which was based on the thermal relaxation time of the melanocyte (size 7 μm; 1 μsec), which is not the primary target in melanocytic nevus. The cluster of nevus cells (100 μm) probably lends itself to treatment with a millisecond laser rather than a nanosecond laser. Thus, normal mode pigment-specific lasers and pulsed ablative lasers (CO2/erbium [Er]:yttrium aluminum garnet [YAG]) are more suited to treat acquired melanocytic nevi. The complexities of treating this disorder can be overcome by following a structured approach by using lasers that achieve the appropriate depth to treat the three subtypes of nevi: junctional, compound, and dermal. Thus, junctional nevi respond to Q-switched/normal mode pigment lasers, where for the compound and dermal nevi, pulsed ablative laser (CO2/Er:YAG) may be needed. If surgical excision is employed, a wide margin and proper depth must be ensured, which is skill dependent. A lifelong follow-up for recurrence and melanoma is warranted in predisposed individuals, although melanoma is decidedly uncommon in most acquired melanocytic nevi, even though histological markers may be seen on evaluation.

Using dermoscopic criteria and patient-related factors for the management of pigmented melanocytic nevi

OBJECTIVE

To review recent dermoscopy studies that provide new insights into the evolution of nevi and their patterns of pigmentation as they contribute to the diagnosis of nevi and the management of pigmented melanocytic nevi.

DATA SOURCES

Data for this article were identified by searching the English and German literature by Medline and Journals@Ovid search for the period 1950 to January 2009.

STUDY SELECTION

The following relevant terms were used: dermoscopy, dermatoscopy, epiluminescence microscopy (ELM), surface microscopy, digital dermoscopy, digital dermatoscopy, digital epiluminescence microscopy, digital surface microscopy, melanocytic skin lesion, nevi, and pigmented skin lesions. There were no exclusion criteria.

DATA SYNTHESIS

The dermoscopic diagnosis of nevi relies on the following 4 criteria (each of which is characterized by 4 variables): (1) color (black, brown, gray, and blue); (2) pattern (globular, reticular, starburst, and homogeneous blue pattern); (3) pigment distribution (multifocal, central, eccentric, and uniform); and (4) special sites (face, acral areas, nail, and mucosa). In addition, the following 6 factors related to the patient might influence the pattern of pigmentation of the individual nevi: age, skin type, history of melanoma, UV exposure, pregnancy, and growth dynamics.

CONCLUSIONS

The 4 x 4 x 6 "rule" may help clinicians remember the basic dermoscopic criteria of nevi and the patient-related factors influencing their patterns. Dermoscopy is a useful technique for diagnosing melanocytic nevi, but the clinician should take additional factors into consideration to optimize the management of cases of pigmented lesions.

Melanocytic aggregation in the skin: diagnostic clues from lentigines to melanoma

Pigmented skin lesions are among the most common skin lesions. Among them, melanocytic proliferations are morphologically diverse and their behavior may be difficult to discern with certainty. Researchers must be able to distinguish melanocytic from nonmelanocytic pigmented skin lesions and, in particular, benign from malignant lesions. The majority of these lesions can be diagnosed with ease; however, a minority of cases is difficult and have potential for error. The authors have systematically analyzed the clinical and dermoscopic features of melanocytic skin lesions, so as to increase in vivo diagnostic accuracy.

Management and dermoscopy of fast-growing nevi in pregnancy: case report and literature review

BACKGROUND

The relationship between pregnancy and a change in melanocytic nevi is still controversial. Moreover, management of the rapid evolution of a nevus in an unauspicious melanocytic lesion can be a clinical challenge in pregnancy.

METHODS

This article examines a case of a fast-growing deep penetrating nevus in a pregnant woman and provides a literature review of articles relative to pregnancy and nevi change, the management of fast-growing pigmented lesions, and the role and usefulness of dermoscopy in these cases.

RESULTS

Recent studies have documented that pregnancy is not associated with any significant change in the size of melanocytic nevi. The management of fast-growing melanocytic lesions during this period compulsorily leans toward excision. Dermoscopy can be useful, providing clinicohistopathologic correlations and a better assignment of the lesion.

CONCLUSION

This case report and review provide important management considerations for nevi during pregnancy. Early intervention with aggressive treatment measures is the best management for fast-growing lesions, and epiluminescence dermoscopy can assist the management, although still remaining a second-level examination, useful for documentation and for a better classification of the lesion.

Blue-whitish veil-like structure as the primary dermoscopic feature of combined nevus

The combined nevus is a clinical simulator of melanoma, and clinical examination alone can be inadequate to diagnose this melanocytic pigmented skin lesion. Dermoscopy is a useful tool to differentiate the features related to each type of nevus. We report two cases of combined nevi dermoscopically characterized by a diffuse blue-whitish pigmentation similar to the blue-whitish veil, suggesting the diagnosis of melanoma.

Dermoscopic Evolution of a Congenital Combined Nevus in Childhood

BACKGROUND

A combined nevus most commonly consists of a blue nevus in combination with a Clark or Spitz nevus. Dermoscopically, combined nevus can mimic melanoma owing to the presence of dermoscopic features common to both types of lesions. Benign clinical and dermoscopic changes can occur in nevi over time, especially in children and young adults.

OBJECTIVE

To describe the dermoscopic evolution of a congenital combined nevus showing unusual dermoscopic features.

METHODS

Digital dermoscopic analysis was performed at the initial visit and after 8 months. The lesion was surgically excised and histopathologically examined.

RESULTS

An asymptomatic plaque with a central blue area and peripheral brown pigmentation located on the back of a 13-year-old boy was diagnosed dermoscopically as combined nevus. Dermoscopic analysis 8 months later showed color changes from steel blue to gray-blue and black in the central area of the lesion, an increased number of blue-black dots or globules, and peripheral irregular streaks. Histopathology revealed typical features of a congenital combined nevus (blue nevus + compound nevus).

CONCLUSION

Over time, congenital combined nevus may show clinical and dermoscopic changes in size, color, and structure. Surgical excision is recommended when clinical and dermoscopic features are equivocal and the diagnosis of melanoma cannot be ruled out.