Recognition of early melanoma: a monocentric dermoscopy follow-up study comparing de novo melanoma with nevus-associated melanoma

Multiple Primary Melanoma: A Five-Year Prospective Single-Center Follow-Up Study of Two MC1R R/R Genotype Carriers

BACKGROUND

Multiple primary melanoma (MPM) is a diagnostic challenge even with ancillary imaging technologies available to dermatologists. In selected patients' phenotypes, the use of imaging approaches can help better understand lesion characteristics, and aid in early diagnosis and management.

METHODS

Under a 5-year prospective single-center follow-up, 58 s primary melanomas (SPMs) were diagnosed in two first-degree relatives, with fair skin color, red hair, green eyes, and personal history of one previous melanoma each. Patients' behavior and descriptive demographic data were collected from medical records. The information on the first two primary melanomas (PMs) were retrieved from pathology reports. The characteristics of 60 melanomas were collected from medical records, video dermoscopy software, and pathology reports. Reflectance confocal microscopy (RCM) was performed prior to excision of 22 randomly selected melanomas.

RESULTS

From February 2018 to May 2023, two patients underwent a pooled total of 214 excisional biopsies of suspect lesions, resulting in a combined benign versus malignant treatment ratio (NNT) of 2.0:1.0. The number of moles excised for each melanoma diagnosed (NNE) was 1.7:1.0 and 6.9:1.0 for the female and male patient respectively. The in-situ melanoma/invasive melanoma ratio (IIR) demonstrated a higher proportion of in-situ melanomas for both patients. From June 2018 to May 2023, a total of 58 SPMs were detected by the combination of total body skin exam (TBSE), total body skin photography (TBSP), digital dermoscopy (DD), and sequential digital dermoscopy imaging (SDDI) via comparative approach. The younger patient had her PM one month prior to the second and third cutaneous melanomas (CMs), characterizing a case of synchronous primary CM. The male older relative had a total of 7 nonsynchronous melanomas.

CONCLUSIONS

This CM cohort is composed of 83.3% in-situ melanoma and 16.7% invasive melanoma. Both patients had a higher percentage of SPM with clinical nevus-like morphology (84.5%), global dermoscopic pattern of asymmetric multiple component (60.3%) and located on the lower limbs (46.6%). When RCM was performed prior to excision, 81% of SPM had features suggestive of malignancy. As well, invasive melanomas were more frequent in the lower limbs (40%). In the multivariate model, for the two high-risk patients studied, the chance of a not associated with nevus ("de novo") invasive SPM diagnosis is 25 times greater than the chance of a diagnosis of a nevus-associated invasive SPM.

The Association of Nevus-Associated Melanoma with Common or Dysplastic Melanocytic Nevus: A Systematic Review and Meta-Analysis

Background: Cutaneous melanoma has an adjacent nevus remnant upon histological examination in 30% of cases (nevus-associated melanoma, NAM), while it appears de novo for 70% of tumors. Regarding NAM arising in acquired melanocytic nevus, currently there is no evidence on whether NAM more frequently develops in association with a dysplastic or common melanocytic nevus. Objectives: To conduct a systematic review and meta-analysis to investigate the proportion of dysplastic or common melanocytic nevus in NAM associated with acquired nevus. Methods: A systematic literature search is conducted using PubMed, Scopus, and the Cochrane Library. The PRISMA checklist is used. Studies reporting patients diagnosed with NAM arising in an acquired common or dysplastic melanocytic nevus are included. A meta-analysis of proportions is performed using the random-effects model. The magnitude of heterogeneity is assessed with the I² statistic. Results: A total of 22 studies with 2174 NAMs with an acquired nevus (dysplastic or common) are included. The proportion of dysplastic nevus in NAM varies considerably in the included studies, ranging from 0% to 100%. In the meta-analysis, the overall estimate of the proportion of having a dysplastic nevus in NAM is 51% (95% CI: 39-63%) with high heterogeneity at I²: 95.8% (p < 0.01). A sensitivity meta-analysis of 12 studies that included 30 or more acquired nevus-NAMs (2023 cases) shows that 65% of the NAMs developed in a dysplastic nevus (95% CI: 51-77%). In a meta-analysis of 4 studies reporting invasive-only acquired nevus-NAMs (764 cases), the proportion of dysplastic nevus is 56% (95% CI: 36-75%). Only 2 studies are found reporting in situ NAMs with an acquired nevus, and the pooled estimated proportion of dysplastic nevus is 71% (95% CI: 63-78%). Conclusions: The results of this meta-analysis suggest a higher proportion of dysplastic nevus in acquired nevus-NAM; however, there is considerable uncertainty and high heterogeneity, highlighting the need for future well-designed studies with uniform histopathological definitions for dysplastic nevus remnants which report the type of nevus in NAM separately for invasive melanomas, thin tumors, and by histological subtype.

A review of nevus-associated melanoma: What is the evidence?

Cutaneous melanoma may have an adjacent nevus remnant on histological examination in 30% of cases (nevus-associated melanoma, NAM), while it may appear de novo, without a precursor lesion, in the remaining 70% of cases. Nevus-associated melanoma and the concept of acquired melanocytic nevi serving as precursors of melanoma, has long been considered as a controversial topic. This controversy is, in part, due to their overall low rate of transformation to melanoma and scarce data on the natural history of progression. Another matter of debate regarded the possibility that the reported differences of NAM versus de novo melanoma, were due to an underestimation of NAM in thicker lesions due to obliteration of the nevus component by the tumour. During the last few years, several evidence has accumulated in order to address these controversies. In this review, we present a comprehensive synthesis of the epidemiological, clinical, dermoscopic and genetic findings in NAM, including thin NAM, compared to de novo melanoma. Answering the questions on nevus-associated melanoma may provide further insight on the classification of these tumours and disentangle their biology and route of development from that of de novo melanoma.

Influence of germline genetic variants on dermoscopic features of melanoma

Nevus count is highly determined by inherited variants and has been associated with the origin of melanoma. De novo melanomas (DNMMs) are more prevalent in patients with a low nevus count and have distinctive dermoscopic features than nevus-associated melanomas. We evaluated the impact of nine single nucleotide polymorphisms (SNPs) of MTAP (rs10811629, rs2218220, rs7023329 and rs751173), PLA2G6 (rs132985 and rs2284063), IRF4 (rs12203592), and PAX3 (rs10180903 and rs7600206) genes associated with nevus count and melanoma susceptibility, and the MC1R variants on dermoscopic features of 371 melanomas from 310 patients. All MTAP variants associated with a low nevus count were associated with regression structures (peppering and mixed regression), blue-whitish veil, shiny white structures, and pigment network. SNPs of PLA2G6 (rs132985), PAX3 (rs7600206), and IRF4 (rs12203592) genes were also associated with either shiny white structures or mixed regression (all corrected p-values ≤ .06). Melanomas from red hair color MC1R variants carriers showed lower total dermoscopy score (p-value = .015) and less blotches than melanomas from non-carriers (p-value = .048). Our results provide evidence that germline variants protective for melanoma risk and/or associated with a low nevus count are associated with certain dermoscopic features, more characteristic of de novo and worse prognosis melanomas.

Nevus-associated melanoma: facts and controversies

Nevus-associated melanoma (NAM) is defined on histopathological basis by the coexistence of melanoma and nevus components. Melanomas developing on pre-existing congenital or acquired nevi are usually of the superficial spreading subtype and harbor the BRAFV600E mutation. NAM accounts for almost one-third of melanoma cases As compared to de novo melanoma, NAM develops on younger patients, is more frequently located on the trunk, and is associated with a high nevus count, light eye color and history of frequent sunburns. NAM has been regarded as a model to investigate melanoma origin. Molecular analysis defining the mutation profile of NAM's nevus and melanoma components supported the existence of two pathways of melanoma development, the first not involving clinically visible precursors, the second involving melanocytic nevi as precursors. Concerning diagnosis, dermatoscopy may identify nevus and melanoma components when located side-by-side, but no specific criteria have been described when superimposed. In-vivo reflectance confocal microscopy significantly enhances the recognition of NAM by allowing the detection of nevus remnants when superficially located. Regarding prognosis, NAM is generally thinner and more frequently in-situ than de-novo melanoma. Furthermore, studies reporting survival analysis demonstrated a trend towards better overall, distant-metastasis-free and recurrence-free survival. Although a clinical, phenotypic and molecular profile of NAM has been defined, controversies still exist. In the current review, we widely report and discuss facts and controversies on NAM.

Potential association between oral mucosal nevus and melanoma: A preliminary clinicopathologic study

OBJECTIVES

To assess potential association between oral nevi (ON) and nevus-associated melanoma (NAM), in which melanoma cells coexist with nevus cells.

METHODS

A total of 74 ON patients and 7 NAM patients were retrospectively reviewed. Comparative and regression analyses of clinical and histological data were performed between two groups.

RESULTS

The mean age of the patients with ON was 36.5 years compared with that of 54.7 years of the patients with NAM (p = .008). Gender ratio was female predominance for ON (1.64:1 ratio) and male predominance for NAM (6:1 ratio). The most common location of ON and NAM was the palate (31.1%) and gingiva (71.4%), respectively. Univariate regression analysis revealed that elderly male patients (≥60 years) with junctional ON located on the gingiva correlate with higher risk of melanoma. Multivariate analysis revealed that junctional type of ON was an independent factor (adjusted OR, 38.32; 95% CI, 3.20-458.64; p = .004) associated significantly with increased risk for melanoma.

CONCLUSIONS

The preliminary study for the first time elucidated the clinicopathologic features of a Chinese series of ON and evaluated the potential association between ON and NAM with a limited sample size. Further large multicenter studies are needed to confirm the findings.

Digital dermoscopic changes during follow-up of de-novo and nevus-associated melanoma: a cohort study

BACKGROUND

Nevus-associated melanoma (NAM) has been regarded as a distinct biological entity from de-novo melanoma (DNM); however, static dermoscopy often fails in differentiating these entities. Digital dermoscopic monitoring allows to identify dynamic changes occurring during follow-up; this may improve diagnostic accuracy and potentially our knowledge on NAM biology. We aimed to define main independent factors associated with NAM diagnosis and those influencing follow-up time in a population of melanomas excised at follow-up.

METHODS

A cohort of melanomas excised at follow-up was retrospectively and consecutively selected. NAMs and DNMs were compared according to baseline features and main dermoscopic changes occurring during follow-up. Univariate and multivariable logistic and Cox's regression analysis were performed to respectively define factors associated with NAM diagnosis and those influencing the risk for excision.

RESULTS

Eighty-six melanomas were enrolled, of which 21 (24.4%) were nevus-associated. During follow-up NAMs mainly underwent atypical network modifications (47.6%), followed by inverse network (28.6%) and dermoscopic island (23.8%) worsening or appearance. DNMs were also mainly characterized by atypical network modifications (47.7%), however, a significant proportion of cases underwent irregular pigmentation/dots/globules or regression changes (29.2%), which were rarely seen among NAMs. Furthermore, both multivariable logistic and Cox's regression analysis demonstrated a significant association between NAM and a longer follow-up.

CONCLUSIONS

We demonstrated that among melanomas excised at follow-up, different patterns of dermoscopic changes may be found between NAMs and DNMs. This finding, together with the association of NAM with a longer follow-up time, supports the hypothesis of different biological behavior of these two entities.

Clinical and dermoscopic characteristics of congenital and noncongenital nevus-associated melanomas

BACKGROUND

No specific features of nevus-associated melanoma (NAM) are currently defined.

OBJECTIVE

To identify clinical/dermoscopic features of NAM.

METHODS

Retrospective evaluation of histopathologically diagnosed NAM.

RESULTS

Eighty of 165 NAMs had a clinically recognizable nevus component, often raised or nodular, most frequently characterized by different morphologic clones and/or colors. In 111 of 165 NAMs, dermoscopy showed a nevus component, prevalently characterized by regular dots/clods and structureless brown areas. Clinically, the melanoma component was eccentric/peripheral in 45 of 80 cases and central in 35 of 80; dermoscopically, the figures were 59 of 111 and 52 of 111, respectively. Melanomas associated with congenital nevi (C-NAMs) occur at a younger age and have a thicker Breslow depth than melanomas associated with acquired nevi (NC-NAMs). Dermoscopically, regular dots/globules characterize C-NAMs, and hypopigmented structureless areas characterize NC-NAMs.

LIMITATIONS

Retrospective analysis.

CONCLUSION

C-NAMs are more often central to a congenital nevus, with a clod/globular or structureless brown pattern, typical of young patients. NC-NAMs are frequently hypopigmented nodules/plaques, eccentric/peripheral, with hypopigmented structureless areas, typical of older patients.

Is There More Than One Road to Nevus-Associated Melanoma?

The association of melanoma with a preexisting nevus is still a debated subject. Histopathological data support an associated nevus in approximately 30% of all excised melanomas. The annual risk of an individual melanocytic nevus becoming malignant is extremely low and has been estimated to be approximately 0.0005% (or less than 1 in 200,000) before the age of 40 years, to 0.003% (1 in 33,000) in patients older than 60 years. Current understanding, based on the noticeable, small, truly congenital nevi and nevi acquired early in life, is that the first develops before puberty, presents with a dermoscopic globular pattern, and persists for the lifetime, becoming later a dermal nevus in the adult. In contrast, acquired melanocytic nevi develop mostly at puberty and usually undergo spontaneous involution after the fifth decade of life. The purpose of this review is to analyze the data of the literature and to propose, on the basis of epidemiological and clinical-dermoscopic characteristics, a new model of melanogenesis of nevus-associated melanoma.