Congenital melanocytic naevi

Dermoscopy aids in differentiating café-au-lait macules from congenital melanocytic nevi in patients with darker skin phototypes

Dermoscopy aids in the diagnosis and management of pigmented growths and disorders of pigmentation in children. However, there is limited literature on the dermoscopic appearance of café-au-lait macules (CALMs) and congenital melanocytic nevi in patients with dark skin. We report two cases of young children with dark skin and many hyperpigmented patches in whom dermoscopy was utilized to accurately diagnose CALMs and facilitate testing for neurofibromatosis.

Congenital Melanocytic Nevi Syndrome With Leptomeningeal Melanoma

ABSTRACT

The incidence of congenital melanocytic nevi (CMNs) is 1% to 6% for small- to intermediate-size nevi to 1 in 500,000 for giant size nevi. Large and satellite CMNs are known to be associated with neurocutaneous melanosis and central nervous system malformations such as Dandy-Walker malformation, defects of the vertebra-skull, and intraspinal lipomas. We hereby present a case of CMN syndrome in an 18-year-old girl with leptomeningeal melanoma, evaluated with MRI, adequately staged, and screened with FDG PET.

The spectrum of melanocytic nevi and their clinical implications

The magnitude of the topic of melanocytic nevi (MN) is directly related to its relevance in everyday clinical work. The different MN have different prognostic significance in regard to comorbidity and possible risk of transformation. In addition to the criteria of the ABCDE rule, relevant criteria in the assessment of an MN are the time of occurrence, the growth tendency, the distribution and the comparison with other MN of the respective individual.

The present CME article provides an overview of the knowledge that has been gained with regard to the development and genetic background of MN and any risk of degeneration that may exist. In addition, certain clinical and/or dermatoscopic features may provide the clinician with a decision‐making aid in the management of different MNs.

Ultra-high-frequency ultrasound monitoring of melanomas arising in congenital melanocytic nevi: a case series

The aims of our study were to evaluate with ultra-high-frequency ultrasound (UHFUS) the ultrasound features of congenital melanocytic nevi (CMNs) and malignant melanomas (MMs) arising in CMNs and the correlation between ultrasonographic thickness and histological thickness in MMs. We evaluated 10 patients with small-medium CMNs and 10 patients with MMs arising in small-medium CMNs. We collected patient's data, clinical and dermoscopic features. The UHFUS was performed using a 70 MHz frequency probe to study the ecostructure, shape and vascularization. Breslow thickness was compared with ultrasonographic thickness. In the MMs group the following dermoscopic features were described: hyperpigmentation (n = 9), regression area (n = 6), whitish-blue veil (n = 5), thickened network (n = 5), irregular globules (n = 3), inverse network (n = 2) and striae (n = 1). Hyperpigmentation (n = n = 9), thickened network (n = 7), irregular globules (n = 5), regression area (n = 5), striae (n = 1) and whitish-blue veil (n = 1) were found in the CMNs group. The multicomponent pattern was present in both MMs (n = 4) and in CMNs (n = 5). Moreover, the parameters indicative of suspected malignancy were variously combined in the two groups, without showing significant differences in the statistical analysis; with the exception of the blue veil that correlated with the diagnosis of MM. Ultrasonoghaphic vascularization was an ever-present parameter in MMs (100%), with high intensity of intratumoral signal, as opposed to CMNs. We also found a statistically significant correlation between ultrasound thickness and Breslow thickness. In the future, this technique could implement the diagnostic preoperative phase of MMs arising in CMNs in combination with standard clinical-dermatoscopic evaluation.

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.

One Step Melanoma Surgery for Patient with Thick Primary Melanomas: "To Break the Rules, You Must First Master Them!"

BACKGROUND:

We present to the attention of the medical, dermatological and oncosurgical community data that serves to indicate the indispensability of optimisation of the algorithm and recommendations for diagnosis and surgical treatment of cutaneous melanoma. These recommendations could be referred to different subgroups of patients in different clinical stages as well as to patients with different initial characterisation (histological morphology) of the primary tumours. One step surgery is not a myth, even more, it could prove to be one of the best solutions for some patient collectives with advanced stages of melanoma.

CASE REPORT:

We present a case of a 74 - year old patient with a congenital medium sized melanocytic nevus, located directly above the lateral part of the elbow joint. In one month and a half, an achromatic nodular formation evolves with a diameter of 2.7 x 2.3 cm, prominent over the skin level, painful by palpation and spontaneously bleeding. By the anamnestic, clinical and dermoscopic findings the patient was diagnosed with nodular melanoma associated with a congenital medium sized melanocytic nevus. A primary excision with a field of safety 0.5 cm in all directions was performed. After confirmation of the primary diagnosis (tumour thickness 8 mm with no ultrasonographic detection of enlarged lymph nodes), seven days later are - excision was performed with an additional field of surgical safety of 1.5 cm in all directions.

CONCLUSIONS:

In this case remains unclear the following question: For what reason a preoperative high - frequent ultrasonography (HFUS) is not recommended to be used as it will allow only one surgical excision with the elimination of a tumour with a safety field of 2cm in all directions? The enigma about the obstacles preventing such a rational optimisation of the current diagnostic and therapeutic algorithm in patients with melanomas remains unresolved. One step surgery for cutaneous melanoma is widely used in many countries although it continues to be considered as a matter of dispute for some experts. Once again, by a clinical case and the following analysis, we would like to focus the attention of the dermatosurgical community on this crucial and highly significant problem. Innovations are very often resulting from the simplicity of logic, which unfortunately is not always accepted appropriately.

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).

Dermoscopic Features of Small, Medium, and Large-Sized Congenital Melanocytic Nevi

BACKGROUND

Congenital melanocytic nevi (CMN) are present at birth. It is well known that the presence of large-sized congenital nevus in early life could predict a major risk of developing melanoma.

OBJECTIVE

To investigate the clinical and dermoscopic features of the CMN, to search for and highlight any differences between small-sized, medium-sized, large-sized CMN.

METHODS

A nonrandomized observational study was performed. A total of 108 melanocytic nevi were analysed by clinical and dermoscopic examination.

RESULTS

Of the subjects, 57.4% were aged less than 16 years, 42.6% were aged 16 and more. Of the nevi, 26 had reticular pattern (24.1%), 35 had globular pattern (32.4%), 13 had reticular-globular pattern (12.0%), 16 had homogeneous pattern (14.8%), 6 had reticular-homogeneous pattern (5.6%), 2 had globular-homogeneous pattern (1.9%), 7 had cobblestone pattern (6.5%), 3 had reticular patchy pattern (2.8%). Atypical dots and globules, focal hypopigmentation and perifollicular hypopigmentation are the most common dermoscopic features of CMN. The rarest dermoscopic feature is the blue-whitish veil.

CONCLUSION

Most of the dermoscopic features related with dysplastic nevi up to the present, such as atypical dots and globules, focal hypopigmentation, perifollicular hypopigmentation were observed in CMN, in our study. Congenital nevus and dysplastic nevi may share the same dermoscopic features, therefore it is important to know it is found at birth or not.

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?

Common Pediatric Skin Lesions: A Comprehensive Review of the Current Literature

The timely diagnosis and treatment of dermatologic disease in the pediatric population can be challenging. A basic, yet comprehensive knowledge of common lesions is essential for a successful practice in plastic surgery. In this article, the authors describe vascular, cystic, and pigmented cutaneous lesions that are commonly encountered in the pediatric population. Epidemiology, pathogenesis, clinical course, and management options are discussed for each.

Congenital nevi versus metastatic melanoma in a newborn to a mother with malignant melanoma - diagnosis supported by sex chromosome analysis and Imaging Mass Spectrometry

A 37-year-old pregnant woman presented with a 2-cm irregular reddish nodule on her left upper arm during pregnancy. A biopsy from the lesion showed a 2.2-mm thick malignant melanoma with intravascular invasion, 25 mitosis/mm(2) and no ulceration. Following induction of labor, the patient underwent re-excision with sentinel lymph node biopsy. This showed no residual melanoma and no lymph node metastasis. The newborn boy had multiple pigmented lesions on the trunk, some of which were large and irregular. Two were biopsied and histologic examination showed dense dermal proliferation of medium sized melanocytes with multiple mitotic figures and no maturation with their descent into the dermis, raising suspicion of transplacental metastases. Examination of the placenta failed to show metastatic lesions. Multiplex polymerase chain reaction (PCR)-based genotyping, including testing for amelogenin locus for sex chromosome determination, demonstrated the presence of Y chromosome material in the melanocytes of the newborn's lesions excluding maternal origin. A diagnosis of congenital nevi was rendered. Subsequently, Imaging Mass Spectrometric analysis of the mother's lesion showed proteomic signature expression indicative of malignant melanoma, whereas the two lesions in the newborn showed changes indicative of nevi. This case demonstrates the utility of genotyping and Mass Spectrometry analysis in this challenging clinical scenario.

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.

Rhabdomyosarcoma arising in a giant congenital melanocytic nevus

A number of lesions have been documented to arise within congenital melanocytic nevi (CMNs). Although the most frequent malignancy arising within a CMN is melanoma, the association between rhabdomyosarcoma and CMN has rarely been documented. We present a case arising in a 4-month-old girl with a giant CMN. She presented for evaluation of a pedunculated lesion at the superior gluteal crease that had been present since birth and exhibited rapid growth. Biopsy of the lesion revealed two distinct components: an expansile proliferation of pleomorphic cells with varying degrees of cellularity and a proliferation of banal-appearing melanocytic nevic cells. The cells of the expansile proliferation displayed a wide range of morphologic features, including nests of round cells, spindle-shaped cells, and more differentiated rhabdomyoblasts within a myxoid, highly vascularized stroma. Cross-striations, a marker of skeletal muscle differentiation, were present. These tumor cells were strongly immunoreactive with desmin, myo-D1, and myogenin. Fluorescence in situ hybridization analysis with PAX3/7-FKHR probes was negative. A diagnosis of embryonal rhabdomyosarcoma in association with CMN was made. Initial excision revealed tumor at the margins, and the patient underwent reexcision with subsequent chemotherapy with vincristine, actinomycin D, and cyclophosphamide. She was disease-free at the 6-year follow-up. It has been postulated that the combination of melanocytic and rhabdomyoblastic cells within the same lesion may imply derivation from a common pluripotent stem cell or neural crest cell. Clinicians following patients with giant CMN should consider rhabdomyosarcoma in the differential diagnosis of lesions arising within the nevus.

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.

Primary melanoma of the CNS in children is driven by congenital expression of oncogenic NRAS in melanocytes

NRAS mutations are common in human melanoma. To produce a mouse model of NRAS-driven melanoma, we expressed oncogenic NRAS (NRAS(G12D)) in mouse melanocytes. When NRAS(G12D) was expressed in the melanocytes of developing embryos, it induced melanocyte proliferation and congenital melanocytic lesions reminiscent of human blue nevi but did not induce cutaneous melanoma. Unexpectedly, however, it did induce early-onset primary melanoma of the central nervous system (CNS). The tumors were rapidly proliferating and caused neurologic symptoms, rapid health deterioration, and death. NRAS is not a common driver oncogene of primary melanoma of the CNS in adults, but we report two cases of primary melanoma of the CNS in children, both of which carried oncogenic mutations in NRAS. We conclude that acquisition of somatic mutations in NRAS in CNS melanocytes is a predisposing risk factor for primary melanoma of the CNS in children, and we present a mouse model of this disease.

SIGNIFICANCE

We show that the acquisition of NRAS mutations in melanocytes during embryogenesis is a risk factor for early-onset melanoma of the CNS. We have developed a powerful mouse model to study this rare but devastating childhood disease, and to develop therapeutic approaches for its treatment.

Skin tumors in childhood

BACKGROUND

Dermatologists, paediatricians, and general practitioners are often consulted by worried parents for the evaluation of a cutaneous tumor.

METHODS

Selective literature review.

RESULTS

Only 1-2% of skin tumors excised in children turn out to be malignant when examined histologically. Warning signs of malignancy include rapid growth, firm consistency, diameter exceeding 3 cm, ulceration, a non-movable mass, and presence in the neonatal period. The more common malignant skin tumors in adults-basal cell carcinoma, cutaneous squamous cell carcinoma, and melanoma-are very rare in childhood. Congenital melanocytic nevi and sebaceous nevi bear a lower malignant potential than previously believed; nevertheless, their excision is often indicated. A Spitz nevus can mimic a melanoma both clinically and histologically. Some benign skin tumors of childhood tend to regress spontaneously within a few years but may cause complications at particular locations and when multiple. For infantile hemangiomas requiring systemic treatment because of imminent obstruction or ulceration, propranolol seems to have a far more favorable risk-benefit ratio than corticosteroids.

CONCLUSION

Physicians need specialized knowledge in order to decide whether a skin tumor in a child should be excised, non-surgically treated, or further evaluated, or whether it can be safely left untreated because of the likelihood of spontaneous remission.

[Cutis verticis gyrata with a combined blue and congenital dermal nevus]

Cutis verticis gyrata (CVG) describes a rare thickening and folding of the scalp resembling the outer surface of the brain. Secondary CVG is caused by a variety of diseases such as nevi. A 38-year-old woman presented with a long history of a deformed right parietofrontal scalp. Clinical and histopathologic criteria lead to the diagnosis of CVG secondary to a combined blue and congenital nevus. Reports of malignant melanoma developing in this clinical setting mean that each patient must be followed closely or considered for prophylactic excision.

Expression of the embryonic morphogen Nodal in cutaneous melanocytic lesions

Nodal, a potent embryonic morphogen in the transforming growth factor-beta family, is a proposed key regulator of melanoma tumorigenicity. However, there has been no systematic study of Nodal expression in melanocytic lesions. We investigated Nodal expression by immunohistochemistry in 269 melanocytic lesions, including compound nevi, dysplastic nevi, congenital nevi, Spitz nevi, melanoma in situ, malignant melanoma including the variant desmoplastic melanoma, and metastatic melanoma. We found that the Nodal expression was significantly increased in malignant lesions (including melanoma in situ, malignant melanoma, and metastatic melanoma) compared with compound nevi, Spitz nevi, and dysplastic nevi. Surprisingly, congenital nevi expressed a level of Nodal comparable with malignant lesions, whereas desmoplastic melanoma showed lower expression than nondesmoplastic malignant melanoma (P<0.05). Deep melanoma (Breslow depth >1 mm) displayed a higher percentage of Nodal-positive tumor cells than did superficial melanoma (Breslow depth < or =1 mm), although there was no statistical difference in the overall staining intensity (P=0.18). Melanomas in situ showed a lower level of Nodal expression than did deep melanomas and metastatic melanomas (P<0.05). The low expression of Nodal in normal and dysplastic nevi, and its increasing expression with the progression of malignant lesions, are suggestive of a role for Nodal in melanoma progression.