Large congenital melanocytic nevi: associated risks and management considerations

Histopathological characteristics analysis of giant melanocytic naevi in children

BACKGROUND

The major diagnostic criterion for the giant congenital melanocytic nevus (GCMN) is a size larger than 20 cm in diameter. However, the histopathological origin, pathogenesis, and GCMN progression are not yet completely clear. Unlike other medium or small superficial lesions, histomorphological evaluation is significant for GCMN pathological classification, malignant transformation assessment, and early detection of prognosis.

AIMS

This study aimed to investigate the pathological features of GCMN, including its satellite lesions.

PATIENTS/METHODS

Twenty-three giant naevi and seventeen "satellite lesions" were collected from children aged 1 to 10 in Shanghai Ninth People's Hospital from 2018 to 2020. A histological study was conducted to evaluate their histological appearance. All the data observed and recorded data were statistically analyzed.

RESULTS

In 23 cases of GCMN primary nevus, nevus cells were mainly distributed in the dermal region, with melanocyte proliferation and the presence of nevus nests at the dermal-epidermal junction. However, in satellite nevus, a junctional growth pattern was noted. Additionally, other histopathologic features, including epidermal contour, cell morphology, and architecture disorder also showed significant differences between primary nevus and satellite nevus.

CONCLUSIONS

We demonstrated that the congenital pattern of the main nevus is more obvious than one of the satellite nevus, suggesting that the satellite nevus and the main nevus may occur slightly later than the main nevus. "Satellite nevus" happens as a result of a separate genetic event.

Transcriptomic analysis of mRNA expression in giant congenital melanocytic nevi

BACKGROUND AND OBJECTIVE

GCMN is a sporadic disease with an incidence ranging from 1/20,000 to 1/500000. So far, several studies have found that GCMN is related to somatic mutations, but most of them have focused on known pathogenic genes, and transcriptome sequencing based on large datasets is relatively uncommon. At present, the use of next-generation sequencing technologies and bioinformatics platforms makes genomic information study more comprehensive and efficient. In this study, the transcriptome differences between GCMN lesions and surrounding normal skin tissues were investigated using high-throughput transcriptome sequencing, and hub genes and pathways related to pathogenesis were identified, providing a theoretical foundation for further research into the pathogenesis of GCMN.

METHODS

Pathological skin tissue and surrounding normal skin tissue from GCMN patients, namely the pathological group (PG) and the control group (CG), were obtained. 1. All specimens were stained with HE to ensure that the samples met the experimental requirements. 2. Ten pairs of specimens were selected for high-throughput transcriptome sequencing, and the differentially expressed genes (DEGs) between the PG and the CG were obtained. The DEGs were analyzed by clusterProfiler R software for Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. The function of the subnetwork was analyzed and the hub genes were identified by the STRING database and Cytoscape software. 3. The expression differences of hub genes PTGS2, EGF, and SOX10 in pathological skin tissues and normal skin tissues were verified by qRT-PCR and immunofluorescence staining.

RESULTS

1. HE staining revealed a lot of melanocytes in the dermis and subcutaneous tissues. They were found around the hair follicles, sweat glands, sebaceous glands, and blood vessel walls, or in a specific pattern. 2. The screening threshold was set at p<0.01 and |log2fc|<1, and a total of 1163 DEGs were discovered between the PG and CG, with 519 genes up-regulated and 644 genes down-regulated in the pathological tissues. According to the GO functional analysis, 29 biological processes, 18 cell compositions, and 17 molecular functions were significantly enriched, with the majority of them being related to keratinocytes and the extracellular matrix. There were 779 nodes and 2359 interactions in the protein interaction network. Using the MCODE plug-in, the network was divided into 25 functional clusters. According to ClueGO results, Cluster5 was involved in melanin biosynthesis and melanocyte proliferation. Using 11 operation methods in the Cytohubba plug-in, PTGS2, EGF, and SOX10 in Cluster5 were chosen as hub genes. 3. qRT-PCR and immunofluorescent staining revealed that compared to normal skin tissue, the expression of SOX10 was significantly up-regulated, and the expression of PTGS2 and EGF was significantly down-regulated in pathological skin tissue(P<0.001).

CONCLUSIONS

In GCMN, keratinocytes and extracellular matrix may directly and indirectly affect melanocyte activity. PTGS2, EGF, and SOX10 are important genes and significantly differentially expressed in pathological and normal skin tissues. These findings may serve as a springboard for future research.

Surgical outcomes and psychosocial impact of giant congenital melanocytic nevus surgery: A single-center case series of 136 patients

PURPOSE

The aim of this study was to evaluate the outcomes, complications and psychosocial impact of surgical treatment of giant congenital melanocytic nevus (GCMN).

METHODS

Patients with surgically treated GCMN who attended our clinic between May 2014 and May 2018 were included. Patient demographics and data on the characteristics of the nevus, surgical treatment, and the psychosocial impact (including C-DLQI/DLQI questionnaires) were collected.

RESULTS

One hundred thirty-six patients were included (median age 9 years). Mean age at first surgery was 34 (+/- 61.45) months; 5.53 (+/- 3.69) surgical interventions were necessary to completely excise the nevus. The expanded skin flap was the preferred surgical technique in most locations. Complications were common but not severe. Of the patients studied, 70.4% reported that the surgery had a minor impact on their quality of life (QoL). Patients and caregivers stated that surgical treatment should begin as soon as possible, even in cases where early treatment did not have an impact on their QoL nor on their satisfaction with the surgery (p < 0.05). The lower the patient age at first surgery, the higher the surgeon's satisfaction (p < 0.01).

CONCLUSIONS

Surgical treatment is a safe option for management of GCMN, and has a low impact on QoL. Patients, caregivers, and surgeons agree that the treatment should begin as soon as possible. This is the largest single-center study evaluating surgical treatment in GCMN patients and its psychosocial impact, and the first to take into account the patient, caregivers and dermatologists opinion of surgical results.

Giant Congenital Melanocytic Nevus in a Chinese Newborn

Giant congenital melanocytic nevus (GCMN) is a rare birthmark disorder that reportedly affects 1 in 20,000-500,000 live births. Here, we present a case of GCMN in a 1-day-old newborn that covered the entire abdomen, reaching the thigh and chest, and laterally toward the backward aspect of the trunk to involve the entire back and buttocks. We discuss the diagnostic and treatment approach.

Congenital melanocytic naevi: An up-to-date overview

Congenital melanocytic naevi are hamartomas of the neuroectoderm caused by genetic mosaicism. Congenital melanocytic naevi are seen in 1-6% of all live births and commonly classified based on the projected size in adults. Congenital melanocytic naevi appear in different colours, shapes, and sizes, and occasionally present with complications. In this review, we sought to evaluate congenital melanocytic naevi, their clinical, dermatoscopic, and reflectance confocal microscopic features, behavioural pattern over time, new trends in classification, underlying genetic factors and their influence on clinical manifestations and management, associated risks, complications, magnetic resonance imaging findings and their management in the light of recent literature.

Surgical treatment of children and youth with congenital melanocytic nevi: self- and proxy-reported opinions

PURPOSE

The role of surgery in the management of congenital melanocytic nevi (CMN) is controversial. Data on surgical outcomes and predictors of satisfaction remain scarce.

METHODS

An online survey was employed following worldwide recruitment of youth aged 14-25 years (n = 44) and parents of children ≤ 18 years (n = 249) with CMN to query patterns of treatment and satisfaction with and opinions about the benefits of surgery.

RESULTS

In proxy-reports, 121 of 249 (49%) and in self-reports 30 of 44 (75%) participants underwent CMN excision. The most common reasons for surgery were psychosocial determinants, aesthetic improvement, and melanoma risk reduction. The overall satisfaction with surgical management was good, although no predictors for satisfaction could be identified. Higher current age of the child was found to predict decision regret in proxy-reports. Most participants indicated that having a scar is more socially acceptable than a CMN. Opinions differed on whether surgery should be deferred until the child is old enough to be involved in the decision-making process.

CONCLUSIONS

Whether and when to perform surgery in children with CMN is a multifaceted question. Awareness of common concerns as well as risks and benefits of surgery are essential to ensure critical reflection and balanced decision-making.

Giant congenital melanocytic nevus in a Cameroonian child: a case report

BACKGROUND

Giant congenital melanocytic nevus is a very rare condition characterized by a large skin lesion and an increased risk of complications like neurocutaneous melanosis and malignant transformation. Reports of giant congenital melanocytic nevus are scarce in the sub-Saharan African literature and here we present a case of this disease in a Cameroonian adolescent.

CASE PRESENTATION

A 12-year-old Cameroonian girl from the "Baka" ethnic group, with no relevant family and medical histories presented with a progressively extensive brownish-black nodular hypertrophic skin lesion of approximately 45 cm, which she had had since she was 2-days old. The lesion covered her entire back giving an appearance of "turtle child", which was highly suggestive of a giant congenital melanocytic nevus. She was booked in for a surgical intervention organized by a health campaign within her community. Meanwhile she was provided with psychological support and her family was counseled on warning signs of complications which would warrant an urgent consultation.

CONCLUSIONS

Here we presented a case of giant congenital melanocytic nevus, apparently the first in the Cameroonian literature. In view of the potential severe complications as well as psychological trauma of this pathology, we draw clinicians' attention to this extremely rare but real pathology in our country, for a timely diagnosis and management.

A prospective study of patients with large congenital melanocytic nevi and the risk of melanoma

BACKGROUND:

Large congenital melanocytic nevus (LCMN) is considered a risk factor for melanoma, although the magnitude of this risk is controversial.

OBJECTIVE:

To evaluate the risk of melanoma development in patients with LCMN seen at a dermatology referral center in Brazil during a twelve-year period. To the best of our knowledge, there are no published similar studies on large congenital melanocytic nevus in South America.

METHODS:

Our prospective cohort included only patients with congenital nevi ≥20cm. The cumulative risk of developing melanoma and the standardized morbidity ratio were calculated for patients followed up prospectively for at least 1 month.

RESULTS:

Sixty-three patients were enrolled in this study. One patient who developed melanoma prior to enrollment was excluded, and five were eliminated because of insufficient follow-up time. Mean follow-up for the remaining 57 patients was 5.5 years (median 5.2 years). Median age of entry into the study was 2.6 years. Most patients (75.4%) underwent only clinical observation. Melanomas occurred in 2 (3.5%) patients. Five-year cumulative risk for melanoma was 4.8% (95% CI: 1.9-11.5%). Standardized morbidity ratio was 1584 (95% CI: 266-5232, p<0.001).

STUDY LIMITATIONS:

The small sample size reduces the accuracy of risk estimates.

CONCLUSIONS:

This study analyzed prospectively for the first time data from South America demonstrating that patients with LCMN have a higher risk of developing melanoma than the general population (p<0.001).

Brazilian guidelines for diagnosis, treatment and follow-up of primary cutaneous melanoma - Part II

The last Brazilian guidelines on melanoma were published in 2002. Development in diagnosis and treatment made updating necessary. The coordinators elaborated ten clinical questions, based on PICO system. A Medline search, according to specific MeSH terms for each of the 10 questions was performed and articles selected were classified from A to D according to level of scientific evidence. Based on the results, recommendations were defined and classified according to scientific strength. The present Guidelines were divided in two parts for editorial and publication reasons. In this second part, the following clinical questions were answered: 1) which patients with primary cutaneous melanoma benefit from sentinel lymph node biopsy? 2) Follow-up with body mapping is indicated for which patients? 3) Is preventive excision of acral nevi beneficious to patients? 4) Is preventive excision of giant congenital nevi beneficious to patients? 5) How should stages 0 and I primary cutaneous melanoma patients be followed?

Classification of neurological abnormalities in children with congenital melanocytic naevus syndrome identifies magnetic resonance imaging as the best predictor of clinical outcome

Background

The spectrum of central nervous system (CNS) abnormalities described in association with congenital melanocytic naevi (CMN) includes congenital, acquired, melanotic and nonmelanotic pathology. Historically, symptomatic CNS abnormalities were considered to carry a poor prognosis, although studies from large centres have suggested a much wider variation in outcome.

Objectives

To establish whether routine MRI of the CNS is a clinically relevant investigation in children with multiple CMN (more than one at birth), and to subclassify radiological abnormalities.

Methods

Of 376 patients seen between 1991 and 2013, 289 fulfilled our criterion for a single screening CNS MRI, which since 2008 has been more than one CMN at birth, independent of size and site of the largest naevus. Cutaneous phenotyping and radiological variables were combined in a multiple regression model of long‐term outcome measures (abnormal neurodevelopment, seizures, requirement for neurosurgery).

Results

Twenty‐one per cent of children with multiple CMN had an abnormal MRI. Abnormal MRI was the most significant predictor of all outcome measures. Abnormalities were subclassified into group 1 ‘intraparenchymal melanosis alone’ (n = 28) and group 2 ‘all other pathology’ (n = 18). Group 1 was not associated with malignancy or death during the study period, even when symptomatic with seizures or developmental delay, whereas group 2 showed a much more complex picture, requiring individual assessment.

Conclusions

For screening for congenital neurological lesions a single MRI in multiple CMN is a clinically relevant strategy. Any child with a stepwise change in neurological/developmental symptoms or signs should have an MRI with contrast of the brain and spine to look for new CNS melanoma.

What's already known about this topic?

Multiple congenital melanocytic naevi (CMN; more than one lesion at birth) can be associated with abnormalities of the central nervous system (CNS). The spectrum of these abnormalities includes congenital and acquired pathologies, melanotic and nonmelanotic lesions, rendering the term ‘CMN syndrome’ more appropriate than ‘neurocutaneous melanosis’.

Symptomatic CNS abnormalities were previously thought to carry a universally poor prognosis, although cohort data in the last decade have argued against this.

What does this study add?

A single CNS magnetic resonance imaging scan in multiple CMN, independent of projected adult size or site of the largest naevus, and ideally in the first 6 months of life, is currently an appropriate screening strategy.

An abnormal result is a better statistical predictor of clinical outcome than cutaneous phenotype.

Clinical management is altered as a result of the radiological result.

Giant congenital melanocytic nevus

Giant congenital melanocytic nevus is usually defined as a melanocytic lesion present at birth that will reach a diameter ≥ 20 cm in adulthood. Its incidence is estimated in <1:20,000 newborns. Despite its rarity, this lesion is important because it may associate with severe complications such as malignant melanoma, affect the central nervous system (neurocutaneous melanosis), and have major psychosocial impact on the patient and his family due to its unsightly appearance. Giant congenital melanocytic nevus generally presents as a brown lesion, with flat or mammilated surface, well-demarcated borders and hypertrichosis. Congenital melanocytic nevus is primarily a clinical diagnosis. However, congenital nevi are histologically distinguished from acquired nevi mainly by their larger size, the spread of the nevus cells to the deep layers of the skin and by their more varied architecture and morphology. Although giant congenital melanocytic nevus is recognized as a risk factor for the development of melanoma, the precise magnitude of this risk is still controversial. The estimated lifetime risk of developing melanoma varies from 5 to 10%. On account of these uncertainties and the size of the lesions, the management of giant congenital melanocytic nevus needs individualization. Treatment may include surgical and non-surgical procedures, psychological intervention and/or clinical follow-up, with special attention to changes in color, texture or on the surface of the lesion. The only absolute indication for surgery in giant congenital melanocytic nevus is the development of a malignant neoplasm on the lesion.

The molecular pathology of melanoma: an integrated taxonomy of melanocytic neoplasia

Melanomas comprise multiple biologically distinct categories, which differ in cell of origin, age of onset, clinical and histologic presentation, pattern of metastasis, ethnic distribution, causative role of UV radiation, predisposing germ-line alterations, mutational processes, and patterns of somatic mutations. Neoplasms are initiated by gain-of-function mutations in one of several primary oncogenes, which typically lead to benign melanocytic nevi with characteristic histologic features. The progression of nevi is restrained by multiple tumor-suppressive mechanisms. Secondary genetic alterations override these barriers and promote intermediate or overtly malignant tumors along distinct progression trajectories. The current knowledge about the pathogenesis and clinical, histologic, and genetic features of primary melanocytic neoplasms is reviewed and integrated into a taxonomic framework.

Dermoscopy for the pediatric dermatologist part III: dermoscopy of melanocytic lesions

Melanocytic nevi encompass a variety of lesions, including blue, Spitz, congenital, and acquired nevi. These nevi can occasionally manifest clinical morphologies resembling melanoma, and the presence of such nevi in children can elicit anxiety in patients, parents, and clinicians. Dermoscopy has been shown to increase the diagnostic accuracy for melanoma and to help differentiate melanoma from nevi, ultimately aiding in the decision-making process as to whether to perform a biopsy. Dermoscopy is the perfect instrument to use during the evaluation of pigmented skin lesions in children because it is painless and provides important information for the clinician that can assist in formulating appropriate management decisions. This review highlights the most common benign dermoscopic patterns encountered in nevi and discuss the 10 most common dermoscopic structures seen in melanomas. Lesions manifesting a benign dermoscopic pattern and lacking any melanoma-specific structures do not need to be excised and can safely be monitored. In contrast, melanomas will invariably deviate from the benign nevus patterns and will usually manifest at least 1 of the 10 melanoma-specific structures: atypical network, negative network, streaks, crystalline structures, atypical dots and globules, irregular blotch, blue-white veil, regression structures, peripheral brown structureless areas, and atypical vessels. It is important to be cognizant of the fact that melanomas in childhood usually do not manifest the clinical ABCD features. Instead, they are often symmetric, amelanotic, nodular lesions. Although the clinical appearance may not be alarming, with dermoscopy they will invariably manifest at least one melanoma-specific structure, the most common being atypical vascular structures and crystalline structures.

Congenital melanocytic nevi: where are we now? Part I. Clinical presentation, epidemiology, pathogenesis, histology, malignant transformation, and neurocutaneous melanosis

Congenital melanocytic nevi (CMN) are present at birth or arise during the first few weeks of life. They are quite common, may have a heritable component, and can present with marked differences in size, shape, color, and location. Histologic and dermatoscopic findings may help suggest the diagnosis, but they are not entirely specific. CMN are categorized based on size, and larger lesions can have a significant psychosocial impact and other complications. They are associated with a variety of dermatologic lesions, ranging from benign to malignant. The risk of malignant transformation varies, with larger CMN carrying a significantly higher risk of malignant melanoma (MM), although with an absolute risk that is lower than is commonly believed. They may also be associated with neuromelanosis, which may be of greater concern than cutaneous MM. The information presented herein aims to help dermatologists determine when it is prudent to obtain a biopsy specimen or excise these lesions, to obtain radiographic imaging, and to involve other specialists (eg, psychiatrists and neurologists) in the patient's care.

New recommendations for the categorization of cutaneous features of congenital melanocytic nevi

BACKGROUND

The diameter of congenital melanocytic nevi (CMN) has served as the lone criterion for determining risks of adverse outcomes such as melanoma. A standardized description of additional morphologic features is needed.

OBJECTIVE

We sought to develop a consensus-based standardized categorization of cutaneous features of CMN and to test agreement among experts on the proposed scheme.

METHODS

An interdisciplinary group of experts in the field of CMN was surveyed using a detailed questionnaire. Applicability of the expert consensus-based scheme was tested for interobserver agreement.

RESULTS

The principal variable of the consensus-based categorization is CMN size, based on maximal diameter the CMN is projected to attain by adulthood. CMN size categories include: small (<1.5 cm); medium (M1: 1.5-10 cm, M2: >10-20 cm); large (L1: >20-30 cm, L2: >30-40 cm); and giant (G1: >40-60 cm, G2: >60 cm). In addition, number of satellite nevi in the first year of life is categorized into none, 1 to 20, more than 20 to 50, and more than 50 satellites. Additional descriptors of CMN include anatomic localization, color heterogeneity, surface rugousity and presence of hypertrichosis (described as none, moderate, marked), and presence of dermal or subcutaneous nodules (none, scattered, extensive). Assessment of consistency among 3 experts showed moderate to excellent interobserver agreement for categorization of the clinical descriptors (kappa values 0.54-0.93).

LIMITATIONS

Applicability of the proposed scheme was tested in a virtual setting and only among experts.

CONCLUSION

The proposed categorization scheme for CMN was agreed upon by experts and showed good interobserver agreement. Such standardized reporting of patients with CMN facilitates the development of an international clinical database for the study of large and giant CMN.

A prospective study of cutaneous findings in newborns in the United States: correlation with race, ethnicity, and gestational status using updated classification and nomenclature

OBJECTIVE

To provide incidence data based on ethnicity, prematurity, and body site for vascular, pigmented, and other common congenital cutaneous findings; to compare these results with previously published prospective studies; and to define updated nomenclature, classification, clinical course, and prognostic factors for the pediatric practitioner to promote a better understanding of benign versus more worrisome birthmarks.

STUDY DESIGN

This prospective study enrolled 594 infants in San Diego, California. Cutaneous examination was performed by pediatric dermatologists in the first 48 hours of life, with subsequent longitudinal contact via telephone, and repeat evaluations if any new lesions were reported by parents. Incidence rates were calculated by ethnicity and prematurity status.

RESULTS

The most common vascular lesion was nevus simplex (83%), followed by infantile hemangioma (4.5% by age 3 months), capillary malformation (0.3%), and rapidly involuting congenital hemangioma (0.3%). Pigmented lesions seen at birth included dermal melanocytosis (20%), congenital melanocytic nevi (2.4%), and café au lait macules (2%). Other common skin findings were erythema toxicum neonatorum (7%), milia (8%), and sebaceous gland hyperplasia (42.6%).

CONCLUSION

This study of congenital cutaneous lesions, using current nomenclature and data acquired by pediatric cutaneous lesion experts, provides data regarding the role of race and ethnicity in the incidence of birthmarks, and provides valid data on the prevalence of infantile hemangioma.

[New aspects of congenital melanocytic nevi]

In recent years, prospective studies with increasing patient numbers have been published on the subject of congenital melanocytic nevi (CMN) and neurocutaneous melanocytosis (NCM). Moreover, medical experts and patient support groups have intensified their collaboration. This article summarizes current aspects of pathogenesis, clinical features, and therapy of CMN and NCM.