Dermoscopic features of melanomas associated with MC1R variants in Spanish CDKN2A mutation carriers

Clinicopathologically Defined Naevus Subtypes and Melanoma Risk

Early detection of melanoma is a major determinant in disease outcome and drives the number of (over)excised naevi in clinical practice. This study aimed to evaluate demographic features and melanoma risk of clinically suspicious, mainly flat naevus subtypes. Based on the methodology of ex vivo dermoscopy and derm dotting, the 12 most prevalent naevus subtypes were identified in a collection of over 7000 naevi excised for medical reason. Dermoscopical, histopathological and clinical features of these subtypes were described. In addition, the association with melanoma history, histopathological atypia and melanoma occurrence within naevi was compared. Nearly half of the naevi removed for medical reasons were of the hypermelanotic subtype with no or mild histopathological atypia and low melanoma association, suggesting overtreatment in daily practice. Contrarily, the subtypes atypical lentiginous naevus and orange pulverocytic flat naevus were associated with higher proportions of (severe) atypia and melanoma (history). We believe these subtypes may reflect different tumoural and/or (germline) genetic entities with different melanoma risk. The data from this study may direct further prospective research on specific naevus subtypes in order to obtain better insights in associated clinical/genetic factors and melanoma risk.

Melanocortin-1 receptor (MC1R): a review for dermatologists

Melanocortin-1 receptor (MC1R) and its variants have a pivotal role in melanin synthesis. However, MC1R has been associated to non-pigmentary pathways related to DNA-repair activities and inflammation. The aim of this review is to provide an up-to-date overview about the role of MC1R in the skin. Specifically, after summarizing the current knowledge about MC1R structure and polymorphisms, we report data concerning the correlation between MC1R, phenotypic traits, skin aging, other diseases and skin cancers and their risk assessment through genetic testing.

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.

Familial Melanoma and Susceptibility Genes: A Review of the Most Common Clinical and Dermoscopic Phenotypic Aspect, Associated Malignancies and Practical Tips for Management

A family history of melanoma greatly increases the risk of developing cutaneous melanoma, a highly aggressive skin cancer whose incidence has been steadily increasing worldwide. Familial melanomas account for about 10% of all malignant melanomas and display an inheritance pattern consistent with the presence of pathogenic germline mutations, among which those involving CDKN2A are the best characterized. In recent years, a growing number of genes, such as MC1R, MITF, CDK4, POT1, TERT, ACD, TERF2IP, and BAP1, have been implicated in familial melanoma. The fact that individuals harboring these germline mutations along with their close blood relatives have a higher risk of developing multiple primary melanomas as well as other internal organ malignancies, especially pancreatic cancer, makes cascade genetic testing and surveillance of these families of the utmost importance. Unfortunately, due to a polygenic inheritance mechanism involving multiple low-risk alleles, genetic modifiers, and environmental factors, it is still very difficult to predict the presence of these mutations. It is, however, known that germline mutation carriers can sometimes develop specific clinical traits, such as high atypical nevus counts and specific dermoscopic features, which could theoretically help clinicians predict the presence of these mutations in prone families. In this review, we provide a comprehensive overview of the high- and intermediate-penetrance genes primarily linked to familial melanoma, highlighting their most frequently associated non-cutaneous malignancies and clinical/dermoscopic phenotypes.

Dermoscopic Criteria, Histopathological Correlates and Genetic Findings of Thin Melanoma on Non-Volar Skin

Dermoscopy is a non-invasive, in vivo technique that allows the visualization of subsurface skin structures in the epidermis, at the dermoepidermal junction, and in the upper dermis. Dermoscopy brought a new dimension in evaluating melanocytic skin neoplasms (MSN) also representing a link between clinical and pathologic examination of any MSN. However, histopathology remains the gold standard in diagnosing MSN. Dermoscopic-pathologic correlation enhances the level of quality of MSN diagnosis and increases the level of confidence of pathologists. Melanoma is one of the most genetically predisposed among all cancers in humans. The genetic landscape of melanoma has been described in the last years but is still a field in continuous evolution. Melanoma genetic markers play a role not only in melanoma susceptibility, initiation, and progression but also in prognosis and therapeutic decisions. Several studies described the dermoscopic specific criteria and predictors for melanoma and their histopathologic correlates, but only a few studies investigated the correlation among dermoscopy, pathology, and genetic of MSN. The aim of this work is to review the published data about dermoscopic features of melanoma, their histopathological correlates with regards also to genetic alterations. Particularly, this review will focus on low-CSD (cumulative sun damage) melanoma or superficial spreading melanoma, high-CSD melanoma, and nevus-associated 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.

Dermoscopy comparative approach for early diagnosis in familial melanoma: influence of MC1R genotype

BACKGROUND

MC1R polymorphisms interact with CDKN2A mutations modulating melanoma risk and contribute to a less suspicious clinical and dermoscopic appearance of melanomas. Different strategies, including dermoscopic comparative approach and digital monitoring, are used for the melanoma diagnosis in this context.

OBJECTIVE

To analyse the diagnostic accuracy of the morphologic approach and comparative approach in dermoscopy, and to detect melanoma in familial melanoma (FamMM) patients according to different genetic backgrounds.

METHODS

Two independent readers evaluated 415 lesions belonging to 25 FamMM: 26 melanomas (62% in situ, 36% early invasive) and 389 naevi, blinded for dermoscopic and histopathologic diagnosis, following two different steps. First step-Randomized: all lesions were randomly located in one single folder. Second step-Comparative approach: the lesions were clustered by patient. Sensitivity, specificity and number needed to excise (NNE) for melanoma diagnosis were calculated for both diagnostic strategies. Sensitivity and specificity were also assessed regarding the genetic background.

RESULTS

The comparative approach showed lower sensitivity compared to the morphologic approach (69.2 and 73.1 vs. 76.9 both readers) but better specificity (95.9 and 95.1 vs. 84.3 and 90.2, respectively). NNE was better in the comparative approach. The readers had more difficulties diagnosing lesions from CDKN2A mutation carriers with red hair colour (RHC) MC1R variants.

CONCLUSION

The comparative approach can be useful in high-risk patients to decrease the NNE. Early melanomas in CDKN2A carriers with RHC polymorphisms are more difficult to diagnose even with the comparative approach and benefit from the detection of changes during digital dermoscopy monitoring for early diagnosis.

Phenotypic and genotypic analysis of amelanotic and hypomelanotic melanoma patients

BACKGROUND

Amelanotic/hypomelanotic melanoma is associated with poorer outcomes due to a more advanced disease stage at diagnosis.

OBJECTIVE

To determine phenotypic risks and genotypic associations with amelanotic/hypomelanotic melanoma to develop a clinical and genetic profile that could assist in identifying high-risk individuals.

METHODS

The Brisbane Naevus Morphology Study conducted from 2009 to 2016 has recruited a core of 1254 participants. Participants were drawn from a combination of volunteers from dermatology outpatient clinics, private dermatology clinics, the Brisbane Longitudinal Twin Study and QSkin study. Case participants had a personal history of melanoma and control participants no personal history of melanoma. We specifically examined seven known candidate pigmentation and melanoma genes and pigmentary phenotypic characteristics in participants with amelanotic/hypomelanotic melanoma compared to pigmented melanomas. This assayed single nucleotide polymorphisms in MC1R, TYR, HERC/OCA2, IRF4, MTAP, PLA2G6 and MITF.

RESULTS

Forty-seven participants had at least one amelanotic/hypomelanotic melanoma, and 389 had pigmented melanomas, with amelanotic/hypomelanotic melanoma patients significantly older than pigmented melanoma participants (63.3 ± 13.0 vs. 54.6 ± 15.3 years; P < 0.001). Amelanotic/hypomelanotic melanoma patients were more likely than pigmented melanoma patients to have red hair (34% vs. 15%; P = 0.01), severe hand freckling (13% vs. 5%; P = 0.01) and propensity to sunburn (63% vs. 44%; P = 0.01). MC1R R/R genotype was much more frequent in our amelanotic/hypomelanotic melanoma population (31.1% vs. 11%; P < 0.001; OR 26.4 vs. 5.9; control 1.0). Amelanotic/hypomelanotic melanoma was associated with TYR rs1126809*A/A [OR (CI 95%) 2.7 (1.1-6.8) vs. 1.2 (0.8-1.9)] and PLA2G6 rs11570734*A/A [OR (CI 95%) 3.7 (1.0-13.6) vs. 1.3 (0.9-2.0)]. The MTAP melanoma risk SNP genotype, associated with darker pigmentation, (rs4636294*A/A) was less common in amelanotic/hypomelanotic melanoma patients [OR (CI 95%) 0.8 (0.3-2.1) vs. 2.0 (1.3-3.1)].

CONCLUSIONS

Knowledge of phenotypic and genotypic associations of amelanotic/hypomelanotic melanoma can help predict risks and associations of this difficult to diagnose melanoma, which may ultimately assist clinical management and patient skin self-examination.

Familial Melanoma: Diagnostic and Management Implications

Background

An estimated 5%-10% of all cutaneous melanoma cases occur in families. This review describes susceptibility genes currently known to be involved in melanoma predisposition, genetic testing of familial melanoma patients, and management implications.

Results

CDKN2A is the major high-penetrance susceptibility gene with germline mutations identified in 20%-40% of melanoma families. A positive CDKN2A mutation status has been associated with a high number of affected family members, multiple primary melanomas, pancreatic cancer, and early age at melanoma onset. Mutations in the other melanoma predisposition genes-CDK4, BAP1, TERT, POT1, ACD, TERF2IP, and MITF-are rare, overall contributing to explain a further 10% of familial clustering of melanoma. The underlying genetic susceptibility remains indeed unexplained for half of melanoma families. Genetic testing for melanoma is currently recommended only for CDKN2A and CDK4, and, at this time, the role of multigene panel testing remains under debate. Individuals from melanoma families must receive genetic counseling to be informed about the inclusion criteria for genetic testing, the probability of an inconclusive result, the genetic risk for melanoma and other cancers, and the debatable role of medical management. They should be counseled focusing primarily on recommendations on appropriate lifestyle, encouraging skin self-examination, and regular dermatological screening.

Conclusions

Genetic testing for high-penetrance melanoma susceptibility genes is recommended in melanoma families after selection of the appropriate candidates and adequate counseling of the patient. All patients and relatives from melanoma kindreds, irrespective of their mutation status, should be encouraged to adhere to a correct ultraviolet exposure, skin self-examination, and surveillance by physicians.

The Melanocortin 1 receptor and its influence on naevi and melanoma in dark-skinned phenotypes

It is well appreciated that melanocortin 1 receptor variants can produce a fair skinned and red-haired phenotype that has a strong association with increased melanoma risk. These patients are easily recognised and given appropriate attention. What may not be appreciated is that darker-skinned individuals may also carry melanocortin 1 receptor variant alleles and that they can also be at increased risk of melanoma. Considering that melanocortin 1 receptor is crucial for melanocyte proliferation, regulation and differentiation do the naevi of these darker-skinned individuals have specific features that help identify them as carrying one of these melanocortin 1 receptor variants and do melanomas that develop in dark-skinned melanocortin 1 receptor variant carriers have particular characteristics?

Melanocortin 1 receptor (MC1R) polymorphisms' influence on size and dermoscopic features of nevi

The melanocortin 1 receptor (MC1R) is a highly polymorphic gene. The loss-of-function MC1R variants ("R") have been strongly associated with red hair color phenotype and an increased melanoma risk. We sequenced the MC1R gene in 175 healthy individuals to assess the influence of MC1R on nevus phenotype. We identified that MC1R variant carriers had larger nevi both on the back [p-value = .016, adjusted for multiple parameters (adj. p-value)] and on the upper limbs (adj. p-value = .007). Specifically, we identified a positive association between the "R" MC1R variants and visible vessels in nevi [p-value = .033, corrected using the FDR method for multiple comparisons (corrected p-value)], dots and globules in nevi (corrected p-value = .033), nevi with eccentric hyperpigmentation (corrected p-value = .033), a high degree of freckling (adj. p-value = .019), and an associative trend with presence of blue nevi (corrected p-value = .120). In conclusion, the MC1R gene appears to influence the nevus phenotype.

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

Melanocytic nevi are a strong phenotypic marker of cutaneous melanoma risk. Changes in nevi during childhood and adolescence make these prime periods for studying nevogenesis. Insights gained by the study of nevi in childhood have implications for melanoma detection in both adults and children. A more comprehensive understanding of the morphologic characteristics of nevi in different anatomic locations, in association with the patient's age and pigmentary phenotype may aid in the identification of melanomas. When monitoring melanocytic lesions over time, it is essential to differentiate normal from abnormal change. This review summarizes the rapidly expanding body of literature relevant to nevus phenotype, particularly in the context of our experience with the Study of Nevi in Children (SONIC) Project.

Characterization of individuals at high risk of developing melanoma in Latin America: bases for genetic counseling in melanoma

Purpose:

CDKN2A is the main high-risk melanoma-susceptibility gene, but it has been poorly assessed in Latin America. We sought to analyze CDKN2A and MC1R in patients from Latin America with familial and sporadic multiple primary melanoma (SMP) and compare the data with those for patients from Spain to establish bases for melanoma genetic counseling in Latin America.

Genet Med18 7, 727–736.

Methods:

CDKN2A and MC1R were sequenced in 186 Latin American patients from Argentina, Brazil, Chile, Mexico, and Uruguay, and in 904 Spanish patients. Clinical and phenotypic data were obtained.

Genet Med18 7, 727–736.

Results:

Overall, 24 and 14% of melanoma-prone families in Latin America and Spain, respectively, had mutations in CDKN2A. Latin American families had CDKN2A mutations more frequently (P = 0.014) than Spanish ones. Of patients with SMP, 10% of those from Latin America and 8.5% of those from Spain had mutations in CDKN2A (P = 0.623). The most recurrent CDKN2A mutations were c.-34G>T and p.G101W. Latin American patients had fairer hair (P = 0.016) and skin (P < 0.001) and a higher prevalence of MC1R variants (P = 0.003) compared with Spanish patients.

Genet Med18 7, 727–736.

Conclusion:

The inclusion criteria for genetic counseling of melanoma in Latin America may be the same criteria used in Spain, as suggested in areas with low to medium incidence, SMP with at least two melanomas, or families with at least two cases among first- or second-degree relatives.

Genet Med18 7, 727–736.

High incidence of primary melanomas in an MC1R RHC homozygote/CDKN2A mutant genotype patient

Melanoma incidence in Australia remains the highest in the world; hence understanding its causation is paramount for future therapeutic developments. Multiple primary melanomas are also common occurrences among the Australian population with identified risk factors such as personal and family history of melanoma, fair skin type, dysplastic naevus syndrome and history of significant ultraviolet exposure. The roles of both environmental and genetic factors have been elucidated in melanoma development, but the synergy of interactions between the two remains complex given the heterogeneous nature of the disease. We present a rare case of a 57-year-old female with 20 cutaneous melanomas and review the role of genetic and environmental factors in development of her multiple primary melanomas.

CDKN2A mutations could influence the dermoscopic pattern of presentation of multiple primary melanoma: a clinical dermoscopic genetic study

BACKGROUND

Patients who develop cutaneous melanoma are at increased risk of developing a second primary melanoma. There are many aetiological reasons by which the risk of a second melanoma increases. Among others, genetic factors may contribute to modulating this risk. The risk of identifying a CDKN2A germline mutation increases with the number of primary melanomas and with the presence of familial history of melanoma. Patients with melanoma are especially encouraged to have regular follow-up visits with their dermatologist to perform clinical and dermatoscopic examination. In particular, dermoscopy could be very useful in multiple primary melanoma (MPM) patients.

OBJECTIVES

To analyse the clinical and dermatoscopic features of multiple melanomas, focusing on those features that are more frequently found in the same patient to recognize them earlier and understand whether they appear with the similar peculiar dermatoscopic features, especially in CDKN2A carriers.

METHODS

Medical records of MPM patients were selected from a database including 1065 patients with histopathologically proven melanoma diagnosis, all treated at the dermatology clinic of the University of Florence from 2000 to 2013. Pictures of melanoma were independently and blindly administered to three dermatologist experts in dermoscopy to evaluate the presence or absence of ABCD criteria for each clinical image, and the main pattern for the dermoscopic images. The results were then analyzed and crossed to rate the clinical and dermoscopic features of MPM.

RESULTS

Seventy five (7.0%) of 1065 patients included in our database were found to carry an MPM disease. Among them, we selected 12 (16%) patients with three or more MPMs. The presence of the CDKN2A melanoma susceptibility gene was observed in 4/12 (33.33%) patients; two patients presented the C500G and c.5 + 1delG polymorphisms in the CDKN2A gene. In CDKN2A carriers, each patient showed a similar and specific dermatoscopic pattern in their lesions.

CONCLUSIONS

Even being aware of the limitations of this study, according to hereditary characters and their modes of transmissions, we could speculate that for each patient with a CDKN2A germline mutation, it is possible to find the same kind of dermoscopical pattern among their melanocytic tumours.

The light and the dark of dermatoscopy in the early diagnosis of melanoma: facts and controversies

Early diagnosis remains the best method to reduce melanoma and non-melanoma skin cancer-related mortality and morbidity. Dermatoscopy was first introduced at the end of the last century, and besides the strict criticism that it initially received, the majority of the scientific community presently considers it revolutionary in the field of melanocytic lesion diagnostics. Cumulative evidence provides definite data that dermatoscopy improves the clinicians' diagnostic accuracy for melanoma compared with other clinical diagnostic approaches. There remain some barriers for its use such as lack of training, lack of time, and lack of reimbursement, as well as persisting skepticism about its true utility. In the current contribution, we focus on false beliefs and facts concerning dermatoscopy in the early diagnosis of melanoma and shed some light on some of the remaining "dark sides" of this issue.

Dermoscopic features of cutaneous melanoma are associated with clinical characteristics of patients and tumours and with MC1R genotype

BACKGROUND

Several algorithms are available for the dermoscopic diagnosis of pigmented skin lesions. The MC1R gene is a key determinant of pigmentation characteristics that are established host-related melanoma risk factors.

OBJECTIVES

To investigate the association of dermoscopic features of sporadic cutaneous melanomas with clinical characteristics of patients and corresponding tumours and with genetic changes in the MC1R and BRAF genes.

METHODS

A total of 64 dermoscopic images of 62 patients were scored by ABCD rule and modified pattern analysis. Detailed patients' and melanomas' characteristics were collected. Patients were screened for germline MC1R variants and related melanomas for somatic V600 BRAF mutations.

RESULTS

A lower total dermoscopic score (TDS) was observed in melanomas of patients with red hair (P = 0.019), due to reduced dermoscopic structures (P < 0.0001). Thicker melanomas showed higher TDS values (P = 0.021) due to sharper borders (P < 0.0001) and higher number of colors (P = 0.004). An atypical pigment network was prevalent in superficial spreading melanomas (P = 0.010), in individuals with dark skin (P = 0.043) and hair color (P = 0.001). An atypical vascular pattern was more frequent in nodular (P < 0.0001) and thick (P < 0.0001) melanomas, in individuals with skin type I-II (P = 0.037), blond or red hair color (P = 0.032) and blue or green eyes (P = 0.014). Melanomas of MC1R R carriers showed lower TDS value (P = 0.037), reduced dermoscopic structures (P = 0.001) and lower prevalence of atypical pigment network (P = 0.001). No differences were identified between BRAF-mutated or wild-type melanomas.

CONCLUSIONS

We suggest a phenotypic/MC1R profile for melanoma patients and their tumours. Melanomas of MC1R R carriers show a significant lower TDS value, with reduced dermoscopic structures, and a lower prevalence of an atypical pigment network. Non-carriers of MC1R R variants develop melanomas dermoscopically characterized by an atypical pigment network which is prevalent in superficial spreading melanomas, in patients with dark complexion and less frequent in red-haired individuals.

CDKN2A and MC1R variants influence dermoscopic and confocal features of benign melanocytic lesions in multiple melanoma patients

Non-invasive diagnostic tools are effective in the histomorphological study of melanocytic lesions. The role of melanoma susceptibility genes on melanocytic nevi histopathological features is not clear. The current study aimed to correlate genetic alterations and histomorphological features of melanocytic nevi. Clinical, dermoscopic and confocal features of 34 multiple melanoma patients and 34 controls were compared. Among patients with melanoma, carriers of CDKN2A mutations and/or MC1R variants, and wild-type genes were also compared. In patients with melanoma, a lighter phototype (P = 0.051), a higher number of nevi (P < 0.01) and clinically atypical nevi (P < 0.01) were observed. At dermoscopy, these nevi showed a complex pattern (P = 0.011), atypical network (P = 0.018) and irregular pigmentation (P = 0.037); at confocal, an irregular meshwork pattern (P = 0.026) with atypical nests (P = 0.016) and an inflammatory infiltrate (P = 0.048) were observed. Among patients with melanoma genetically tested, CDKN2A G101W mutation carriers were more frequently younger (P = 0.023), with clinically atypical nevi (P = 0.050), with cytological atypia (P = 0.033) at confocal. G101W mutation and MC1R variants carriers showed hypopigmented nevi (P = 0.002) and, at confocal, roundish cells infiltrating the junction (P = 0.019). These data suggest an influence of CDKN2A mutation and MC1R variants in the development of dysplastic melanocytic lesions. Non-invasive histomorphological evaluation, together with genetic studies, improves melanoma risk identification and early diagnosis, for a patient-tailored management.

Dermoscopic nevus patterns in skin of colour: a prospective, cross-sectional, morphological study in individuals with skin type V and VI

BACKGROUND

Most of the knowledge on the prevailing dermoscopic patterns of acquired melanocytic nevi (AMV) is based on studies in Caucasians, while little research focuses on the dermoscopic variability in nevi in skin of colour.

OBJECTIVE

To analyse the prevalent dermoscopic nevus patterns in subjects with a skin type (ST) V and VI.

METHODS

Prospective, cross-sectional, morphological study was conducted in six clinics with enrolment of consecutive individuals with a ST V or VI. Digital dermoscopic images of selected representative AMN were assessed for dermoscopic colours, morphological patterns and pigment distribution.

RESULTS

Analysis of 300 nevi from subjects with ST V and VI revealed significant differences in the nevus pattern between these two groups. The majority of nevi in ST V revealed a reticular pattern, whereas persons with ST VI more frequently exhibited a structureless pattern. Black, blue and grey were more frequent in ST VI, whereas the vast majority of nevi in ST V individuals showed dark brown colour.

CONCLUSIONS

Our study provides new insights into the nevus pattern in individuals with a dark pigmentary trait, which may aid the diagnosis and management of nevi in this patients group.

High-definition optical coherence tomography imaging of melanocytic lesions: a pilot study

High-definition optical coherence tomography (HD-OCT) is a non-invasive in vivo imaging technique with cellular resolution based on the principle of conventional optical coherence tomography. The objective of this study was to evaluate HD-OCT for its ability to identify architectural patterns and cytologic features of melanocytic lesions. All lesions were examined by one observer clinically and using dermoscopy. Cross-sectional HD-OCT images were compared with histopathology. En face HD-OCT images were compared with reflectance confocal microscopy (RCM). Twenty-six melanocytic lesions of 26 patients were imaged. Identification of architectural patterns in cross-sectional mode and cytologic features of pigmented cells in the epidermis, dermo-epidermal junction, papillary dermis, and superficial reticular dermis in the en face mode was possible by HD-OCT. HD-OCT provides morphological imaging with sufficient resolution and penetration depth to discriminate architectural patterns and cytologic features of pigmented cells in epidermis and dermis. The method appears to offer the possibility of additional three-dimensional structural information complementary to that of RCM, albeit at a slightly lower lateral resolution. The diagnostic potential of HD-OCT regarding malignant melanoma is not high enough for ruling out a diagnosis of malignant melanoma.

Phenotypic characterization of nevus and tumor patterns in MITF E318K mutation carrier melanoma patients

A germline polymorphism of the microphthalmia transcription factor (MITF) gene encoding a SUMOylation-deficient E318K-mutated protein has recently been described as a medium-penetrance melanoma gene. In a clinical assessment of nevi from 301 volunteers taken from Queensland, we identified six individuals as MITF E318K mutation carriers. The phenotype for 5 of these individuals showed a commonality of fair skin, body freckling that varied over a wide range, and total nevus count between 46 and 430; in addition, all were multiple primary melanoma patients. The predominant dermoscopic signature pattern of nevi was reticular, and the frequency of globular nevi in carriers varied, which does not suggest that the MITF E318K mutation acts to force the continuous growth of nevi. Excised melanocytic lesions were available for four MITF E318K carrier patients and were compared with a matched range of wild-type (WT) melanocytic lesions. The MITF staining pattern showed a predominant nuclear signal in all sections, with no significant difference in the nuclear/cytoplasmic ratio between mutation-positive or -negative samples. A high incidence of amelanotic melanomas was found within the group, with three of the five melanomas from one patient suggesting a genetic interaction between the MITF E318K allele and an MC1R homozygous red hair color (RHC) variant genotype.

MC1R variants predisposing to concomitant primary cutaneous melanoma in a monozygotic twin pair

Background

Concomitant primary cutaneous melanoma in monozygotic twins has been reported in only two pairs but in neither of them genetic analysis was performed. Two high-penetrance susceptibility genes, CDKN2A and CDK4 and one low-penetrance gene, MC1R, are well-defined genetic risk factors for melanoma. MITF has been recently identified as a novel intermediate risk melanoma-predisposing gene.

Case presentation

We describe the extraordinary occurrence of a primary cutaneous invasive melanoma in two 44-year-old identical, female twins, on the same body site within 30 days of each other and report for the first time the genetic analysis of melanoma susceptibility genes in both twins. Data on characteristics of the twins were collected through a standardized questionnaire and skin examination. Exons 1α, 1β, 2 and 3 of CDKN2A, exon 2 of CDK4, the entire open reading frame of MC1R and the recently described MITF c.952 G > A (p.Glu318Lys) variant were investigated by direct sequencing. Sequencing analysis of the high-penetrance susceptibility genes showed no changes in CDKN2A and in exon 2 of the CDK4 gene. Both patients were heterozygous for the same CDKN2A UTR c.*29C > G variant. Interestingly, the same two heterozygous variants of the MC1R were identified in both twins: the c.451C > T (p.Arg151Cys) and the c.456C > A (p.Tyr152*) variants. Neither patient showed the c.952 G > A (p.Glu318Lys) substitution in the MITF gene.

Conclusions

Identification of two high-risk MC1R variants in our identical twins in the absence of CDKN2A and CDK4 mutations highlights the contribution of low penetrance genes, such as MC1R, in melanoma susceptibility.

Reflectance confocal microscopy accurately discriminates between benign and malignant melanocytic lesions exhibiting a 'dermoscopic island'

BACKGROUND

The 'dermoscopic island' is a term that was recently proposed to design an area of a pigmented lesion with a uniform dermoscopic pattern different from the remainder of the lesion. The positive predictive value of this sign for the diagnosis of melanoma is about 50%.

OBJECTIVE

The purpose of our study was to see if reflectance confocal microscopy (RCM) permitted to accurately distinguish between nevi and melanoma in such lesions.

METHODS

Five lesions of five consecutive unselected patients, with a dermoscopic island but no feasible clear cut diagnosis on the basis of dermoscopy alone were examined by RCM before excision for histopathological evaluation.

RESULTS

Two lesions corresponded to nevi, and three lesions were early melanomas arising on a benign naevus in one case, and on a dysplastic naevus in two cases. In all five cases, RCM permitted to make the correct diagnosis, with a very good correlation with conventional histopathology.

CONCLUSION

Reflectance confocal microscopy appears as a promising tool not only to enhance the early diagnosis of melanoma but also to avoid unnecessary excisions of lesions with a dermoscopic island.

Agreement of dermatopathologists in the evaluation of clinically difficult melanocytic lesions: how golden is the 'gold standard'?

BACKGROUND

The 'gold standard' for the diagnosis of melanocytic lesions is dermatopathology. Although most of the diagnostic criteria are clearly defined, the interpretation of histopathology slides may be subject to interobserver variability.

OBJECTIVES

The aim of this study was to determine the variability among dermatopathologists in the interpretation of clinically difficult melanocytic lesions.

METHODS

This study used the database of MelaFind®, a computer-vision system for the diagnosis of melanoma. All lesions were surgically removed and sent for independent evaluation by four dermatopathologists. Agreement was calculated using kappa statistics.

RESULTS

A total of 1,249 pigmented melanocytic lesions were included. There was a substantial agreement among expert dermatopathologists: two-category kappa was 0.80 (melanoma vs. non-melanoma) and three-category kappa was 0.62 (malignant vs. borderline vs. benign melanocytic lesions). The agreement was significantly greater for patients ≥40 years (three-category kappa = 0.67) than for younger patients (kappa = 0.49). In addition, the agreement was significantly lower for patients with atypical mole syndrome (AMS) (kappa = 0.31) than for patients without AMS (kappa = 0.76).

LIMITATIONS

The data were limited by the inclusion/exclusion criteria of the MelaFind® study. This might represent a selection bias. The agreement was evaluated using kappa statistics. This is a standard method for evaluating agreement among pathologists, but might be considered controversial by some statisticians.

CONCLUSIONS

Expert dermatopathologists have a high level of agreement when diagnosing clinically difficult melanocytic lesions. However, even among expert dermatopathologists, the current 'gold standard' is not perfect. Our results indicate that lesions from younger patients and patients with AMS may be more problematic for the dermatopathologists, suggesting that improved diagnostic criteria are needed for such patients.

Inherited variants in the MC1R gene and survival from cutaneous melanoma: a BioGenoMEL study

Inherited MC1R variants modulate MITF transcription factor signaling, which in turn affects tumor cell proliferation, apoptosis, and DNA repair. The aim of this BioGenoMEL collaborative study in 10 melanoma cohorts was to test the hypothesis that inherited variants thereby moderate survival expectation. A survival analysis in the largest cohort (Leeds) was carried out adjusting for factors known to impact on survival. The results were then compared with data from nine smaller cohorts. The absence of any consensus MC1R alleles was associated with a significantly lower risk of death in the Leeds set (HR, 0.64; 95% CI, 0.46–0.89) and overall in the 10 data sets (HR, 0.78; 95% CI, 0.65–0.94) with some support from the nine smaller data sets considered together (HR, 0.83; 95% CI, 0.67–1.04). The data are suggestive of a survival benefit for inherited MC1R variants in melanoma patients.

Genetics of pigmentation in skin cancer--a review

Skin pigmentation is one of the most overt human physical traits with consequences on susceptibility to skin cancer. The variations in skin pigmentation are dependent on geographic location and population ethnicity. Skin colouration is mainly due to the pigmentation substance melanin, produced in specialized organelles (melanosomes) within dendritic melanocytes, and transferred to neighbouring keratinocytes. The two types of melanin synthesized in well defined chemical reactions are the protective dark coloured eumelanin and the sulphur containing light red-yellow pheomelanin. The events leading to the synthesis of melanin are controlled by signalling cascades that involve a host of genes encoding ligands, receptors, transcription factors, channel transporters and many other crucial molecules. Several variants within the genes involved in pigmentation have been associated with high risk phenotypes like fair skin, brown-red hair and green-blue eyes. Many of those variants have also been implicated in the risk of various skin cancers. The variants within the key pigmentation gene, melanocortin-receptor 1 (MC1R), in particular have been ubiquitously linked with high risk traits and skin cancers involving both pigmentary and non-pigmentary functions and likely interaction with variants in other genes. Many of the variants in other genes, functional in pigmentation pathway, have also been associated with phenotypic variation and risk of skin cancers. Those genes include agouti signalling protein (ASIP), tyrosinase (TYR), tyrosinase-related protein 1 (TYRP1), oculocutaneous albinism II (OCA2), various solute carrier genes and transporters. Most of those associations have been confirmed in genome wide association studies that at the same time have also identified new loci involved in phenotypic variation and skin cancer risk. In conclusion, the genetic variants within the genes involved in skin pigmentation besides influencing phenotypic traits are important determinants of risk of several skin cancers. However, ultimate risk of skin cancer is dependent on interplay between genetic and host factors.

The melanocortin-1 receptor gene polymorphism and association with human skin cancer

The melanocortin-1 receptor (MC1R) is a key gene involved in the regulation of melanin synthesis and encodes a G-protein coupled receptor expressed on the surface of the melanocyte in the skin and hair follicles. MC1R activation after ultraviolet radiation exposure results in the production of the dark eumelanin pigment and the tanning process in humans, providing physical protection against DNA damage. The MC1R gene is highly polymorphic in Caucasian populations with a number of MC1R variant alleles associated with red hair, fair skin, freckling, poor tanning, and increased risk of melanoma and nonmelanoma skin cancer. Variant receptors have shown alterations in biochemical function, largely due to intracellular retention or impaired G-protein coupling, but retain some signaling ability. The association of MC1R variant alleles with skin cancer risk remains after correction for pigmentation phenotype, indicating regulation of nonpigmentary pathways. Notably, MC1R activation has been linked to DNA repair and may also contribute to the regulation of immune responses.