Neurofibromatosis type 1 diagnosed in a child based on multiple juvenile xanthogranulomas and juvenile myelomonocytic leukemia

The changing landscape of pediatric histiocytoses: Birth, life, and transdifferentiation of pediatric histiocytes

Histiocytic neoplasms in the children are very rare, and histiocytoses can occur in the perinatal period. The presumed origins and presentation of specific histiocytoses in the pediatric age group are described. Common and newly described histiocytoses are presented including Langerhans cell histiocytosis, Rosai-Dorfman disease, histiocytic sarcoma, ALK positive histiocytosis, and hemophagocytic lymphohistiocytosis. Molecular findings common to pediatric histiocytoses are also discussed.

Juvenile xanthogranuloma: retrospective analysis of 44 pediatric cases (single tertiary care center experience)

BACKGROUND/OBJECTIVE

Juvenile xanthogranuloma (JXG) is a rarely encountered skin disorder, which is characterized by the proliferation of non-Langerhans cell histiocytes. As JXG primarily affects infants and young children, this study aims to describe the epidemiologic, clinical, and histopathologic characteristics of 44 children diagnosed with JXG at a tertiary health care center.

METHODS

Fourty-four children with a histopathologic diagnosis of JXG between January 2003 and January 2017 were retrospectively reviewed. Data related to epidemiologic, clinical, and histopathologic features were extracted from hospital records.

RESULTS

The mean age of the affected patients was 4.6 years old (range: 0-17 years old) at the time of diagnosis. Twenty-five patients (56.8%) were male, and 19 patients were female (43.2%). Thirty-six children (81.8%) had solitary JXG, one of which was a giant congenital JXG; eight children (18.2%) had eruptive JXG. The heterozygote mutation associated with neurofibromatosis 1 gene was detected in one patient who had both eruptive JXG and numerous café-au-lait spots. Another patient with eruptive JXG was identified to have hypercholesterolemia. None of the children with eruptive JXG developed symptoms or signs of extracutaneous involvement during their clinical follow-up.

CONCLUSION

Since JXG is rarely encountered, there may be a tendency toward over-treatment, given concerns for extracutaneous involvement. However, our review revealed no instances of extracutaneous involvement.

Juvenile Xanthogranuloma: An Entity With a Wide Clinical Spectrum

Juvenile xanthogranulomas (JXGs) are rare, benign lesions that belong to the large group of non-Langerhans cell histiocytoses. JXG presents with 1 or more erythematous or yellowish nodules that are usually located on the head or neck. Most JXG lesions are congenital or appear during the first year of life. Extracutaneous involvement is rare, but the literature traditionally suggests investigating the possibility of ocular compromise. JXG is mainly a clinical diagnosis, but a skin biopsy may sometimes be needed for confirmation. JXGs on the skin are self-limiting and usually do not require treatment. This review describes the clinical and therapeutic aspects of JXG, emphasizing available evidence and the diagnosis of extracutaneous involvement.

Juvenile xanthogranulomas: Examining single, multiple, and extracutaneous presentations

BACKGROUND

Juvenile xanthogranuloma (JXG) is a non-Langerhans cell histiocytosis characterized by yellowish papules in the skin. JXGs most often occur in infancy or early childhood and are typically solitary and asymptomatic, often regressing after several years. While JXGs predominantly occur on the skin, extracutaneous JXGs also exist.

AIMS

In this paper, we review the literature on single, multiple, and visceral JXGs and provide recommendations on monitoring and work-up.

MATERIALS & METHODS

A literature review was conducted with the PubMed database using selective search terms for single, multiple, ocular, and visceral lesions as well as NF1/JMML.

RESULTS / DISCUSSION

JXG is typically a self-limited disorder if lesions are cutaneous and singular. While rare, JXGs may manifest as multiple and extracutaneous lesions. Further screening and referral to specialists may be warranted in these cases based on age and extent of involvement.

CONCLUSION

Our review demonstrates common presentations of single, multiple, and extracutaneous lesions in addition to those that occur with NF1 and JMML. We suggest patients be evaluated on a case-by-case basis by a dermatologist and referred to specialists as appropriate.

After 95 years, it's time to eRASe JMML

Juvenile myelomonocytic leukaemia (JMML) is a rare clonal disorder of early childhood. Constitutive activation of the RAS pathway is the initial event in JMML. Around 90% of patients diagnosed with JMML carry a mutation in the PTPN11, NRAS, KRAS, NF1 or CBL genes. It has been demonstrated that after this first genetic event, an additional somatic mutation or epigenetic modification is involved in disease progression. The available genetic and clinical data have enabled researchers to establish relationships between JMML and several clinical conditions, including Noonan syndrome, Ras-associated lymphoproliferative disease, and Moyamoya disease. Despite scientific progress and the development of more effective treatments, JMML is still a deadly disease: the 5-year survival rate is ~50%. Here, we report on recent research having led to a better understanding of the genetic and molecular mechanisms involved in JMML.

Multiple Juvenile Xanthogranuloma of the Eyelids

Juvenile xanthogranuloma (JXG) is a rare and benign tumor in infants. A solitary lesion on the eyelid has been reported in patients with JXG. We report a 15-year-old boy with multiple involvement of JXG on both eyelids. A mass on the left inner canthus was resected because of disturbance of the visual field and a risk of malignancy in terms of central ulceration in the lesion. The mass was examined by light microscopy. The mass had Touton giant cells with a wreath of nuclei surrounded by foamy histiocytes. No malignancy was observed. The mass showed no recurrence after resection.

Cutaneous Hematolymphoid and Histiocytic Proliferations in Children

This article focuses on cutaneous hematopoietic neoplasms that are more likely to be encountered in the pediatric age-group and includes both lymphoproliferative and histiocytic disorders. The cutaneous hematologic disorders in children have a different epidemiologic profile to what is seen during adulthood. Although mycosis fungoides is the most frequent form of cutaneous lymphoma in adults, it is very rare in children. Because lymphoblastic leukemias and lymphomas are more frequent in the pediatric setting, cutaneous leukemic infiltrates are relatively common in this age-group. Similarly, histiocytic disorders are more common in children, particularly Langerhans cell histiocytosis and juvenile xanthogranuloma. Notably, the histiocytic disorders have undergone significant modifications on their nomenclature in the basis of the molecular characteristics that are present in them. A summary of the most frequent cutaneous hematopoietic disorders in children will be discussed further in this review.

Genetic evaluation of juvenile xanthogranuloma: genomic abnormalities are uncommon in solitary lesions, advanced cases may show more complexity

Juvenile xanthogranuloma is a rare histiocytic proliferation primarily affecting infants and young children, characterized by aberrant infiltration of histiocyte-derived cells in the skin, soft tissues and more rarely, visceral organs. Juvenile xanthogranuloma is generally considered to be a benign disorder; most lesions are solitary cutaneous nodules that resolve spontaneously without treatment. However, cases with extracutaneous involvement, multiple lesions, and/or systemic disease often require aggressive therapy. Though molecular studies have provided evidence of clonality in juvenile xanthogranuloma, in support of a neoplastic process, little is known about the genetic profile of juvenile xanthogranuloma. We used molecular inversion probe array technology to evaluate the genomic characteristics (copy number alterations or copy neutral-loss of heterozygosity) of 21 archived cases of juvenile xanthogranuloma (19 solitary, 1 diffuse cutaneous, 1 systemic). Four cases (19%) showed acquired, clonal alterations. Two lesions from a case of diffuse cutaneous juvenile xanthogranuloma showed distinct profiles: JXG-1a contained trisomy 5 and 17 and JXG-1b contained loss of heterozygosity in 5q. The systemic juvenile xanthogranuloma (JXG-2) showed multiple genomic alterations. Only two of 19 solitary juvenile xanthogranulomas showed abnormal genomic profiles: JXG-3 showed gains on 1q and 11q and JXG-4 showed a 7.2 Mb loss in 3p. No recurrent abnormalities were observed among these cases. The presence of non-recurrent copy number alterations in a subset of samples implies that copy number changes are unlikely driving pathogenesis in juvenile xanthogranuloma, but may be acquired during disease progression. The presence of genomic abnormalities in more advanced cases (ie, systemic and diffuse cutaneous juvenile xanthogranuloma) supports this notion, particularly as the advanced cases of juvenile xanthogranuloma presented more genomic complexity.

Association Between Juvenile Myelomonocytic Leukemia, Juvenile Xanthogranulomas and Neurofibromatosis Type 1: Case Report and Review of the Literature

The occurrence of juvenile myelomonocytic leukemia (JMML), juvenile xanthogranuloma (JXG), and neurofibromatosis type 1 (NF1) together is relatively rare. Approximately only 20 cases have been reported in the literature. It is debated whether children with NF1 and JXG are at higher risk of developing JMML than children with NF1 alone. We present the case of a boy primarily diagnosed with NF1 with coexisting JXG who developed JMML at the age of 22 months. The clinical course from initial presentation to final diagnosis is detailed and the genetic features and hematologic characteristics are discussed. We report this case to underscore the importance of close monitoring of blood count and strict clinical follow-up in children presenting with concurrent NF1 and JXG and provide a possible explanation for this association.

Contributions of Dr. Louis "Pepper" Dehner to the art of cutaneous pathology, the first pediatric dermatopathologist

Dr. Louis "Pepper" Dehner has been one of the most influential surgical pathologists of the last century. Authoring more than 450 publications, he is the premier modern pediatric pathologist. Perhaps, an area that he is less recognized and in which we would like to describe his contributions, is his role as a creator of the art of pediatric dermatopathology. Dr. Dehner has had at least 50 major publications describing, discovering, and orienting the discipline in the fields of fibrohistiocytic disorders of childhood, vascular tumors, and histiocytosis among many others. Dr. Dehner has clearly manifested that while many similarities between adult and pediatric surgical pathology exist, "children get different diseases." It is because of his mindful analysis and translation of the clinico-pathologic and biologic correlative between specific entities and advances in the field he has made that we are honored to describe some of his contributions to this particular area.

An Update on Neurofibromatosis Type 1: Not Just Café-au-Lait Spots and Freckling. Part II. Other Skin Manifestations Characteristic of NF1. NF1 and Cancer

Neurofibromatosis type 1 (NF1) is the most common neurocutaneous syndrome and probably the one best known to dermatologists. Although the genetic locus of NF1 was identified on chromosome 17 in 1987, diagnosis of the disease is still based primarily on clinical observations. The 7 diagnostic criteria of the National Institutes of Health, which were established in 1988, include 3 skin manifestations (café-au-lait spots, freckling on flexural areas, and cutaneous neurofibromas). The age at which these diagnostic lesions appear is variable: onset can be late in some patients while others never develop certain symptoms. Definitive diagnosis may therefore be delayed by years. Although the appearance of the characteristic café-au-lait spots and freckling in the early years of childhood are very suggestive of the disease, these signs are not pathognomonic and, in isolation, do not constitute sufficient evidence to establish a definitive diagnosis. Thus, other diagnoses should be considered in patients whose only symptoms are café-au-lait spots and freckling. By contrast, the presence of multiple cutaneous neurofibromas or at least 1 plexiform neurofibroma is a very specific indication of NF1. Identification of the different types of neurofibroma allows us to confirm the diagnosis and initiate appropriate management.

What's new with common genetic skin disorders?

PURPOSE OF REVIEW

Common genetic disorders such as neurofibromatosis type I (NF1), tuberous sclerosis, basal cell nevus syndrome (BCNS), incontinentia pigmenti, and X-linked ichthyosis have recognizable, cutaneous features. In children, cases often present without a prior diagnosis. This review highlights new information about diagnostic signs and care of affected patients.

RECENT FINDINGS

Disruption of key regulatory pathways causes disorders such as BCNS, NF1, and tuberous sclerosis. The discovery of associated mutations in these pathways has led to molecular targeted therapies. For example, use of drugs such as vismodegib in BCNS and rapamycin in tuberous sclerosis complex is being studied. Also, patient review has refined the diagnostic criteria for tuberous sclerosis and incontinentia pigmenti and expanded the phenotype of X-linked ichthyosis. Preimplantation genetic diagnosis for disorders such as NF1 and incontinentia pigmenti is available.

SUMMARY

Identification of nevus anemicus or juvenile xanthogranuloma in a young child may lead to an early diagnosis of NF1. Rapamycin offers noninvasive treatment for problematic skin lesions in pediatric patients with tuberous sclerosis. Providers can give early advice to affected families that reproductive technologies such as preimplantation genetic diagnosis are a consideration for future pregnancies.