Age related changes in brain MR appearance in the course of neurocutaneous melanosis

Nevi - when to refer

PURPOSE OF REVIEW

Congenital melanocytic nevi (CMN) and acquired nevi are prevalent in pediatric populations, with distinct characteristics and management considerations. This chapter aims to equip pediatricians with knowledge to discern between benign and high-risk nevi, facilitating appropriate referrals and management within primary care settings. Risk factors associated with malignant melanoma (MM) underscore the importance of vigilant monitoring and early referral to dermatology for suspicious lesions.

RECENT FINDINGS

Recent findings highlight the variability in CMN presentation and the evolving diagnostic strategies, emphasizing the need for multidisciplinary approaches to optimize patient outcomes.

SUMMARY

Management of CMN involves tailored surveillance and intervention strategies, with an emphasis on early identification of high-risk features for MM and neurocutaneous melanosis (NCM). Pediatricians play a crucial role in advocating for sun protection practices and facilitating timely referrals, thereby contributing to the overall well being of pediatric patients with nevi.

Incidence of neurocutaneous melanosis in Japanese pediatric patients with congenital melanocytic nevi

Neurocutaneous melanosis (NCM) is a rare, non-hereditary neurocutaneous disorder characterized by excessive melanocytic proliferation in the skin and central nervous system. As no major studies have covered the incidence of NCM among Japanese patients with congenital melanocytic nevi (CMN), we prospectively investigated the incidence of NCM among Japanese patients who underwent initial treatment for CMN. The relationship of CMN and NCM was also investigated. Japanese pediatric patients with CMN under 1 year of age were included between January 2020 and November 2022, and all patients underwent brain MRI to check for NCM in this study. NCM lesions were most frequently seen in the amygdala, followed by the cerebellum, brainstem, and cerebral hemispheres. NCM was diagnosed on brain MRI in 31.6% of the 38 patients with CMN and in 25.0% of patients with no prior examination or treatment. Distribution and size of CMN, number of satellite nevi, rugosity and nodules were strongly associated with the existence of NCM, and these findings may guide a future registry study with a large cohort of CMN patients.

Biogenic Imaging Contrast Agents

Imaging contrast agents are widely investigated in preclinical and clinical studies, among which biogenic imaging contrast agents (BICAs) are developing rapidly and playing an increasingly important role in biomedical research ranging from subcellular level to individual level. The unique properties of BICAs, including expression by cells as reporters and specific genetic modification, facilitate various in vitro and in vivo studies, such as quantification of gene expression, observation of protein interactions, visualization of cellular proliferation, monitoring of metabolism, and detection of dysfunctions. Furthermore, in human body, BICAs are remarkably helpful for disease diagnosis when the dysregulation of these agents occurs and can be detected through imaging techniques. There are various BICAs matched with a set of imaging techniques, including fluorescent proteins for fluorescence imaging, gas vesicles for ultrasound imaging, and ferritin for magnetic resonance imaging. In addition, bimodal and multimodal imaging can be realized through combining the functions of different BICAs, which helps overcome the limitations of monomodal imaging. In this review, the focus is on the properties, mechanisms, applications, and future directions of BICAs.

Central nervous system magnetic resonance imaging abnormalities and neurologic outcomes in pediatric patients with congenital nevi: A 10-year multi-institutional retrospective study

BACKGROUND

High-risk congenital melanocytic nevi (CMN) are associated with abnormalities of the central nervous system (CNS), prompting magnetic resonance imaging (MRI) screening guidelines.

OBJECTIVE

Describe MRI brain and spine abnormalities in children with CMN and report trends between nevus features, MRI findings, and neurologic outcomes.

METHODS

Retrospective review of individuals aged ≤18 years with an MRI of the brain and/or spine and at least 1 dermatologist-diagnosed CMN.

RESULTS

Three hundred fifty-two patients were identified. Forty-six children had CMN that prompted an MRI of the brain and/or spine (50% male, average age at first image, 354.8 days). In these children, 8 (17%) had melanin detected in the CNS, of whom all had >4 CMN. One developed brain melanoma (fatal). In patients without CNS melanin, 4 had concerning imaging. Concerning MRI patients had more neurodevelopmental problems, seizures, neurosurgery, and death than individuals with unremarkable imaging. Three hundred six patients received MRIs for other reasons; none detected melanin. No children with only multiple small CMN (n = 15) had concerning imaging.

LIMITATIONS

Lack of a control group, cohort size, and retrospective methods.

CONCLUSION

MRI of the brain and spine is useful for detecting intervenable abnormalities in high-risk children. Healthy infants with few small CMN may not require screening MRI.

Neurocutaneous melanosis with an intracranial cystic-solid meningeal melanoma in an adult: A case report and review of literature

BACKGROUND

Neurocutaneous melanosis (NCM) is a rare congenital, nonhereditary neurocutaneous syndrome that mainly occurs in children; adult NCM is very rare. Due to its rarity, the clinical features and treatment strategies for NCM remain unclear. The purpose of this study was to explore the clinical features, diagnosis, treatment and prognosis of NCM in adults. Most intracranial meningeal melanomas are solid masses, and cystic-solid malignant melanomas are very rare. Due to the lack of data, the cause of cystic changes and the effect on prognosis are unknown.

CASE SUMMARY

A 41-year-old woman was admitted to the hospital with intermittent headache for 1 mo. Magnetic resonance imaging (MRI) showed a 4.7 cm × 3.6 cm cystic-solid mass in the left temporal lobe with peritumoral edema. The entire mass was removed, and postoperative pathology indicated malignant melanoma.

CONCLUSION

MRI is the first-choice imaging approach for diagnosing central nervous system diseases in NCM patients, although cerebrospinal fluid may also be used. At present, there is no optimal treatment plan; gross total resection combined with BRAF inhibitors and MEK inhibitors might be the most beneficial treatment.

Care of Congenital Melanocytic Nevi in Newborns and Infants: Review and Management Recommendations

A pediatric dermatology expert working group performed a narrative review to describe care related to congenital melanocytic nevi (CMN) in neonates and infants. There are no published guidelines for most aspects of care, including routine skin care and visit intervals. Few guidelines exist for surgical management; newer recommendations favor conservative practice. Emerging evidence contributes to recommendations for screening MRI to evaluate for neural melanosis and related central nervous system complications, however, more research is needed. Risk for melanoma is generally low, but those with large, giant, or multiple CMN have a higher risk. Multidisciplinary care, with a focus on family and patient preferences, is of paramount importance. Without standardized screening and management guidelines, questions abound regarding appropriate physical examination intervals, potential treatment including full or partial excision, timing and frequency of imaging, melanoma risk, and assessment for neural melanosis. This review highlights the current state of knowledge concerning care of patients with CMN, reveals gaps in the literature surrounding skin care, and provides management recommendations. We additionally discuss cutaneous complications of CMN, such as pruritus, hypertrichosis, and wound healing. Resources and references for families and providers can help patients navigate this sometimes challenging diagnosis. Finally, we contribute expert care recommendations to the current body of literature as a foundation for the development of future, more comprehensive care guidelines.

Clinical Follow-Up of Patients with Neurocutaneous Melanosis in a Tertiary Center; Proposed Modification in Diagnostic Criteria

INTRODUCTION

Neurocutaneous melanosis (NCM) is a rare congenital syndrome. Except for some retrospective studies, information on clinical follow-up and management of these patients are limited. This study aimed to review our experience on diagnostic protocol and clinical follow-up of patients with NCM in a referral children's hospital in Iran.

METHODS

Between 2012 and 2019, eight patients with NCM were consecutively managed in our center. Brain magnetic resonance imaging and cutaneous biopsy were done in all patients at diagnosis. Follow-up surveillance and characteristics of the disease are described.

RESULTS

The mean follow-up period was 25.75 ± 13.81 months, and 75% of patients were male. Most magnetic resonance imaging findings were hypersignal lesions in the temporal lobe (75%), cerebellum (62.5%), brainstem (50%), and thalamus (12.5%). Dandy-Walker syndrome was found in 4 patients (50%), and shunt-dependent hydrocephalus was found in 3 patients (37.5%). Cutaneous malignant melanoma and malignant involvement of the central nervous system were found in 2 (25%) and 3 cases (37.5%), respectively. The mortality rate was 37.5%.

CONCLUSIONS

There are no specific guidelines for management of NCM due to the rarity of the disease. This study proposed modifications in diagnostic criteria, as well as recommendations for follow-up surveillance.

Neurocutaneous melanocytosis (melanosis)

Neurocutaneous melanosis (NCM; MIM # 249400; ORPHA: 2481], first reported by the Bohemian pathologist Rokitansky in 1861, and now more precisely defined as neurocutaneous melanocytosis, is a rare, congenital syndrome characterised by the association of (1) congenital melanocytic nevi (CMN) of the skin with overlying hypertrichosis, presenting as (a) large (LCMN) or giant and/or multiple (MCMN) melanocytic lesions (or both; sometimes associated with smaller "satellite" nevi) or (b) as proliferative melanocytic nodules; and (2) melanocytosis (with infiltration) of the brain parenchyma and/or leptomeninges. CMN of the skin and leptomeningeal/nervous system infiltration are usually benign, more rarely may progress to melanoma or non-malignant melanosis of the brain. Approximately 12% of individuals with LCMN will develop NCM: wide extension and/or dorsal axial distribution of LCMN increases the risk of NCM. The CMN are recognised at birth and are distributed over the skin according to 6 or more patterns (6B patterns) in line with the archetypical patterns of distribution of mosaic skin disorders. Neurological manifestations can appear acutely in infancy, or more frequently later in childhood or adult life, and include signs/symptoms of intracranial hypertension, seizures/epilepsy, cranial nerve palsies, motor/sensory deficits, cognitive/behavioural abnormalities, sleep cycle anomalies, and eventually neurological deterioration. NMC patients may be symptomatic or asymptomatic, with or without evidence of the typical nervous system changes at MRI. Associated brain and spinal cord malformations include the Dandy-Walker malformation (DWM) complex, hemimegalencephaly, cortical dysplasia, arachnoid cysts, Chiari I and II malformations, syringomyelia, meningoceles, occult spinal dysraphism, and CNS lipoma/lipomatosis. There is no systemic involvement, or only rarely. Pathogenically, single postzygotic mutations in the NRAS (neuroblastoma RAS viral oncogene homologue; MIM # 164790; at 1p13.2) proto-oncogene explain the occurrence of single/multiple CMNs and melanocytic and non-melanocytic nervous system lesions in NCM: these disrupt the RAS/ERK/mTOR/PI3K/akt pathways. Diagnostic/surveillance work-ups require physical examination, ophthalmoscopy, brain/spinal cord magnetic resonance imaging (MRI) and angiography (MRA), positron emission tomography (PET), and video-EEG and IQ testing. Treatment strategies include laser therapy, chemical peeling, dermabrasion, and surgical removal/grafting for CMNs and shunt surgery and surgical removal/chemo/radiotherapy for CNS lesions. Biologically targeted therapies tailored (a) BRAF/MEK in NCM mice (MEK162) and GCMN (trametinib); (b) PI3K/mTOR (omipalisib/GSK2126458) in NMC cells; (c) RAS/MEK (vemurafenib and trametinib) in LCMNs cells; or created experimental NMC cells (YP-MEL).

Epilepsy in isolated parenchymal neurocutaneous melanosis: A systematic review

PURPOSE

Neurocutaneous melanosis (NCM) is a rare congenital syndrome characterized by giant melanocytic cutaneous nevi and melanosis within the central nervous system (CNS), often sparing leptomeninges and concentrated in the brain parenchyma. Epilepsy and neurodevelopmental abnormalities are the only complications reported in children with isolated parenchymal melanosis. A minority of patients experience drug-resistant epilepsy, and up to now, no predictors of epilepsy prognosis have been identified.

METHODS

In this systematic review, according to preferred reporting items for systematic review and meta-analysis (PRISMA) guidelines, we aggregated clinical cases of patients with isolated parenchymal melanosis affected by epilepsy, in order to recognize predictors of clinical outcome and to clarify indications of available therapeutic approaches.

RESULTS

Sixteen articles (19 patients) were included in the final analysis from initial database research; 4 articles (4 patients) were selected from reference lists and 1 from conference abstracts (1 patient). In our series, distribution of parenchymal melanosis was the best predictor of epilepsy outcome: frequencies of seizure-free patients were different between cases of isolated/bilateral amygdale melanosis and those of multiple localizations (p = 0.037). Failure of antiepileptic drugs (AEDs) and/or surgical epilepsy therapy were associated with poor cognitive outcome (p = 0.03).

CONCLUSION

Antiepileptic drugs were effective in the majority of patients with epilepsy with parenchymal melanosis. In case of multifocal distribution, more than one-third of patients presented a drug-resistant epilepsy. Epilepsy surgery is the best choice in patients with isolated amygdala localization. We propose the recognition of a multifactorial nature of cognitive impairment in neuromelanosis, emphasizing the role of drug-resistant epilepsy.

Malignant transformation of neurocutaneous melanosis (NCM) following immunosuppression

Neurocutaneous melanosis (NCM) is the condition of abnormal melanocyte deposition in the leptomeninges and brain parenchyma. Associated with congenital melanocytic nevi, NCM can result in neurologic deficits, hydrocephalus, and rarely, malignant transformation of cells. We present the case of a 16-year-old boy with NCM who developed malignant leptomeningeal melanoma following immunosuppression with a TNFα inhibitor. To our knowledge, this is the first reported case of a patient with known NCM undergoing malignant transformation after anti-TNF therapy for inflammatory bowel disease.

Neurocutaneous Melanosis in Association With Large Congenital Melanocytic Nevi in Children: A Report of 2 Cases With Clinical, Radiological, and Pathogenetic Evaluation

Background: Melanocytic nevi present at birth, or within the first few months of life, are defined as congenital melanocytic nevi (CMN). Neurocutaneous melanosis (NCM) is a rare disorder, represents pigment cell tumors of the leptomeninges, and occurs in association with large or multiple CMN. NCM carries an extremely poor prognosis. NRAS and BRAF^V600E genetic mutations were reported in CMN. Our aim was to report 2 rare cases of NCM associated with large-sized CMN.

Materials and Methods: Two cases were enrolled, a 19-month-old boy with multiple satellite and giant CMN (GCMN); and a 57-month-old girl with large CMN (LCMN). Both patients had central nervous system (CNS) symptoms, and therefore, were studied from clinical, radiological, and immunohistopathological aspects. Cytogenetic study was done for one of them.

Results: Both patients had CMN located in the head/neck, with no cutaneous melanoma. MRI was the most reliable method for early detection of NCM. NCM was proved in the 2 studied cases by immunohistopathology performed after surgery. The boy with GCMN carried NRAS mutation at codon 61, in addition to the characteristic facial features relevant to RASopathies. Both patients died despite surgical intervention.

Conclusion: Our report highlights the need for pediatricians to be alert to the risk of NCM in association with CMN, especially when a CMN lesion is large, or there are multiple satellite lesions, or the nevus location is at the head or neck. Moreover, in the setting of CMN, the absence of skin melanoma does not exclude the presence of NCM.

The Rare Neurocutaneous Disorders: Update on Clinical, Molecular, and Neuroimaging Features

Phakomatoses, also known as neurocutaneous disorders, comprise a vast number of entities that predominantly affect structures originated from the ectoderm such as the central nervous system and the skin, but also the mesoderm, particularly the vascular system. Extensive literature exists about the most common phakomatoses, namely neurofibromatosis, tuberous sclerosis, von Hippel-Lindau and Sturge-Weber syndrome. However, recent developments in the understanding of the molecular underpinnings of less common phakomatoses have sparked interest in these disorders. In this article, we review the clinical features, current pathogenesis, and modern neuroimaging findings of melanophakomatoses, vascular phakomatoses, and other rare neurocutaneous syndromes that may also include tissue overgrowth or neoplastic predisposition.

New insights into neurocutaneous melanosis

BACKGROUND

Neurocutaneous melanosis is a rare disorder in which children with large cutaneous melanotic nevi have associated melanosis in the brain. Although many affected children have structurally normal brains, some have associated developmental disorders or brain anomalies.

OBJECTIVES

To determine the range of extent of brain melanosis as assessed by magnetic resonance imaging (MRI) and to investigate the frequency and types of associated brain anomalies.

MATERIALS AND METHODS

We retrospectively reviewed brain and spine MRIs of 80 patients with congenital melanocytic nevi (range: 1 day to 22 years of age) affiliated with Nevus Outreach Inc. from 1998 to 2017. Central nervous system (CNS) melanosis was diagnosed when a mass with abnormal parenchymal T1 hyperintensity was seen. The locations of abnormal signal, associated malformations, the presence of contrast enhancement and, in patients with more than one MRI, changes over time were recorded. Associations among findings were analyzed using chi-square test or Fisher exact test.

RESULTS

Brain abnormalities were identified in 33 patients. The most common finding was melanosis in the amygdala, which was found in 31 patients (an isolated finding in 14 patients). Nineteen patients had melanosis in the brainstem, cerebellum, cerebral cortex or thalamus. Cerebral and/or spinal leptomeningeal enhancement was uncommon (five patients). Hindbrain melanosis was associated with cerebellar and pontine hypoplasia (P=0.012). Brain melanosis was most easily seen on T1 images prior to myelination; reduced/loss of visibility was noted as the CNS matured.

CONCLUSION

Brain melanosis is a common manifestation in children with large cutaneous melanotic nevi, most commonly found in the anterior temporal lobes (amygdala), brainstem, cerebellum and cerebral cortex. Hindbrain melanosis is associated with hypoplasia of the affected structures. Early imaging is optimal to provide the greatest sensitivity for diagnosis and to guide proper management.

Bioinspired Multifunctional Melanin-Based Nanoliposome for Photoacoustic/Magnetic Resonance Imaging-Guided Efficient Photothermal Ablation of Cancer

Background: The construction of theranostic nanosystems with concurrently high biosafety and therapeutic performance is a challenge but has great significance for the clinical translation of nanomedicine for combating cancer. Methods: Bio-inspired melanin-based nanoliposomes (Lip-Mel) as theranostic agents were constructed for simultaneous photoacoustic (PA) imaging- and T1-weighted magnetic resonance (MR) imaging-guided photothermal ablation of tumors, which was demonstrated both in vitro and in vivo. The high biosafety of Lip-Mel was also systematically evaluated. Results: The achieved Lip-Mel nanoliposomes demonstrated their imaging capability for both PA and T1-weighted MR imaging (r1 = 0.25 mM-1·s-1) both in vitro and in vivo, providing the potential for therapeutic guidance and monitoring. Importantly, the desirable photothermal-conversion efficiency of the as-prepared Lip-Mel achieved complete eradication of tumors in breast cancer-bearing mice, exhibiting remarkable photothermal-based therapeutic performance. In particular, the efficient encapsulation of melanin into the PEGylated liposome mitigated the potential toxicity of melanin and improved the photothermal performance of the loaded melanin. Systematic in vivo biosafety evaluations demonstrated the high biocompatibility of Lip-Mel at a high dose of 100 mg/kg. Conclusion: In this work, we reported a bioinspired strategy where melanin, a natural product in the human body, is encapsulated into PEGylated nanoliposomes for efficient theranostics with high biocompatibility. This work provides a new strategy for creating desirable theranostic agents with concurrent high biocompatibility and satisfactory theranostic performance through the use of materials that totally originate from biosystems.

Dependency criterion based brain pathological age estimation of Alzheimer's disease patients with MR scans

Objectives

Traditional brain age estimation methods are based on the idea that uses the real age as the training label. However, these methods ignore that there is a deviation between the real age and the brain age due to the accelerated brain aging.

Methods

This paper considers this deviation and obtains it by maximizing the correlation between the estimated brain age and the class label rather than by minimizing the difference between the estimated brain age and the real age. Firstly, set the search range of the deviation as the deviation candidates according to the prior knowledge. Secondly, use the support vector regression as the age estimation model to minimize the difference between the estimated age and the real age plus deviation rather than the real age itself. Thirdly, design the fitness function based on the correlation criterion. Fourthly, conduct age estimation on the validation dataset using the trained age estimation model, put the estimated age into the fitness function, and obtain the fitness value of the deviation candidate. Fifthly, repeat the iteration until all the deviation candidates are involved and get the optimal deviation with maximum fitness values. The real age plus the optimal deviation is taken as the brain pathological age.

Results

The experimental results showed that the separability of the samples was apparently improved. For normal control- Alzheimer’s disease (NC-AD), normal control- mild cognition impairment (NC-MCI), and mild cognition impairment—Alzheimer’s disease (MCI-AD), the average improvements were 0.164 (31.66%), 0.1284 (34.29%), and 0.0206 (7.1%), respectively. For NC-MCI-AD, the average improvement was 0.2002 (50.39%). The estimated brain pathological age could be not only more helpful for the classification of AD but also more precisely reflect the accelerated brain aging.

Conclusion

In conclusion, this paper proposes a new kind of brain age—brain pathological age and offers an estimation method for it that can distinguish different states of AD, thereby better reflecting accelerated brain aging. Besides, the brain pathological age is most helpful for feature reduction, thereby simplifying the relevant classification algorithm.

Estimating the brain pathological age of Alzheimer's disease patients from MR image data based on the separability distance criterion

Traditional age estimation methods are based on the same idea that uses the real age as the training label. However, these methods ignore that there is a deviation between the real age and the brain age due to accelerated brain aging. This paper considers this deviation and searches for it by maximizing the separability distance value rather than by minimizing the difference between the estimated brain age and the real age. Firstly, set the search range of the deviation as the deviation candidates according to prior knowledge. Secondly, use the support vector regression (SVR) as the age estimation model to minimize the difference between the estimated age and the real age plus deviation rather than the real age itself. Thirdly, design the fitness function based on the separability distance criterion. Fourthly, conduct age estimation on the validation dataset using the trained age estimation model, put the estimated age into the fitness function, and obtain the fitness value of the deviation candidate. Fifthly, repeat the iteration until all the deviation candidates are involved and get the optimal deviation with maximum fitness values. The real age plus the optimal deviation is taken as the brain pathological age. The experimental results showed that the separability was apparently improved. For normal control-Alzheimer's disease (NC-AD), normal control-mild cognition impairment (NC-MCI), and MCI-AD, the average improvements were 0.178 (35.11%), 0.033 (14.47%), and 0.017 (39.53%), respectively. For NC-MCI-AD, the average improvement was 0.2287 (64.22%). The estimated brain pathological age could be not only more helpful to the classification of AD but also more precisely reflect accelerated brain aging. In conclusion, this paper offers a new method for brain age estimation that can distinguish different states of AD and can better reflect the extent of accelerated aging.