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

Assessment of Ecotropic Viral Integration Site 2B (EVI2B) Gene in Juvenile Myelomonocytic Leukemia and Neurofibromatosis Type 1 NF1 Tumors

Neurofibromatosis type 1 (NF1) is an autosomal dominant disease that affects the development and growth of various tissues. NF1 is a major risk factor for the development of malignancies, particularly malignant peripheral nerve sheath tumors, optic gliomas, and leukemia. NF1 encodes a neurofibromin. Three genes, EVI2A, EVI2B, and OMGP, are embedded within intron 27b of NF1. However, the function of these genes remains unclear. EVI2A and EVI2B encode for putative transmembrane proteins. Mouse homologs are associated with viral insertions involved in leukemia in mice. Mouse Evi2b has been identified as a direct target gene of C/EBPα, a transcription factor critical for myeloid differentiation. Also possible is that these genes are related to the leukemia observed in patients with NF1. These genes might act as modifiers of NF1 phenotypic variations. Therefore, we investigated the EVI2B gene in leukemia and NF1 tumors. We analyzed DNA from 10, 20, and 3 patients with NF1, leukemia, and NF1-leukemia, respectively, and six NF1 tumor tissues. DNA sequencing analysis was used to identify the viral integration sequence, and the protein amounts and EVI2B gene expression were analyzed by flow cytometry and quantitative real-time PCR techniques. The EVI2B gene expression was increased in cutaneous neurofibroma compared with the control both at the level of protein and mRNA. However, its expression in plexiform neurofibroma was decreased significantly at protein level and increased at mRNA level compare to control. Moreover, integration of 455 bases near the 3' end of the exon was detected. When this integrated sequence was blasted into the NCBI retroviral genome database, an 87% match with the HIV-1 virus envelope gene was obtained. These preliminary results show that EVI2B might be important in NF1 tumorigenesis and leukemia.

Neuroimaging manifestations of paediatric histiocytoses

Histiocytoses are rare multi-system disorders marked by abnormal histiocyte cell proliferation, affecting children with diverse clinical presentations. Classified into five groups in 2016, including Langerhans-related (L), cutaneous (C), malignant (M), Rosai-Dorfman disease (R) and haemophagocytic lymphohistiocytosis (H), newer entities such as ALK-positive histiocytosis have also emerged, heralding the era of molecular (sub)classification. Common entities include Langerhans cell histiocytosis (LCH), Erdheim-Chester disease (ECD), Rosai-Dorfman disease (RDD) and haemophagocytic lymphohistiocytosis (HLH). This pictorial essay aids radiologists in recognising and differentiating paediatric histiocytoses based on unique neuroimaging features.

[Granulomatous dermatoses]

The group of granulomatous dermatoses refers to a multitude of clinically different diseases, which are characterized by a histopathologically similar pattern of inflammation. The cause of granulomatous inflammatory reactions can be infections and also noninfectious stimuli, such as cell disintegration or foreign bodies. The aim of this immunological defence reaction is encapsulation in order to prevent further spread and delimitation from healthy tissue. This is histologically expressed as a granuloma in the sense of a circumscribed aggregation of histiocytes and multinucleated giant cells mostly in dermal connective tissue. The following can be histologically differentiated: sarcoid granuloma characterized by a sparse lymphocytic inflammatory infiltrate and tuberculous granuloma with central necrosis and denser lymphocytic inflammatory infiltrate. Neutrophilic granulocytes together with macrophages occur in suppurative granulomas and palisaded granulomas are characterized by peripherally arrayed macrophages.

Neurofibromatosis in Children: Actually and Perspectives

The three types of neurofibromatosis, namely type 1, type 2, and schwannomatosis, are generally associated with various benign tumors affecting the skin and the nervous system. On rare occasions, especially in patients with neurofibromatosis type 1 (NF1), malignant neoplasms may also be present, several of them possessing a more aggressive course than in individuals without this syndrome. As such, a clear delineation between the three variants of neurofibromatosis is crucial to establish the correct diagnosis and management, as well as predict the neoplasm-related outcomes. Neurofibromin, the principal product of the NF1 gene, is a potent inhibitor of cellular proliferation, having been linked to several key signaling pathways involved in tumor growth. Therefore, it may provide a useful therapeutic target for tumor management in these patients. In this article, we want to present the association between deficiency of neurofibromin and the consequences of the lack of this protein leading to different kinds of malignant tumors. The therapy is still uncertain and most therapeutic options are in development or clinical trials.

Disseminated juvenile xanthogranulomas with ocular involvement: A case report and literature review

Cutaneous juvenile xanthogranuloma is an uncommon disorder usually arising during infancy. Systemic involvement of juvenile xanthogranuloma remains rare, and there are no published guidelines to date on screening extracutaneous manifestations in these patients. Ocular involvement is the most common extracutaneous manifestation of juvenile xanthogranuloma. We present the case of an infant with disseminated juvenile xanthogranulomas and associated ocular involvement and present a review of literature, focusing on identifying risk factors for ocular and systemic involvement in disseminated cases.

Juvenile myelomonocytic leukemia presenting in an infant with a subdural hematoma

BACKGROUND

Juvenile myelomonocytic leukemia (JMML) is a rare childhood hematopoietic disorder typically presenting with hepatosplenomegaly, lymphadenopathy, pallor, fever, and cutaneous findings. The authors report the first case, to our knowledge, of JMML presenting in a pediatric patient with a subdural hematoma.

CASE DESCRIPTION

A 7-month old male with recurrent respiratory infections and a low-grade fever presented with a full fontanelle and an increasing head circumference and was found to have chronic bilateral subdural collections. Abusive head trauma, infectious, and coagulopathy workups were unremarkable, and the patient underwent bilateral burr holes for evacuation of the subdural collections. The postoperative course was complicated by the development of thrombocytopenia, anemia, and an acute subdural hemorrhage which required evacuation. Cytologic analysis of the subdural fluid demonstrated atypical cells, which prompted flow cytometric analysis, a bone marrow biopsy, and ultimately a diagnosis of JMML. Following chemotherapy, the patient's counts improved, and he subsequently underwent a hematopoietic stem cell transplant.

CONCLUSION

Subdural collections may rarely represent the first presenting sign of hematologic malignancies. In patients with a history of recurrent infections and a negative workup for abusive head trauma, clinicians should include neoplastic etiologies in the differential for chronic subdural collections and have a low threshold for fluid analysis.

Chronic Lymphocytic Leukemia in Neurofibromatosis Type 1 Patients: Case Report and Literature Review of a Rare Occurrence

Neurofibromatosis type 1 (NF1) is an autosomal dominant genodermatosis that may also occur as the result of a spontaneous mutation. The diagnosis can be established by the presence of two of the seven National Institutes of Health (NIH) diagnostic criteria; several dermatologic manifestations are NIH criteria used to establish the diagnosis: axillary and inguinal freckling, café-au-lait macules, and neurofibromas. Mucosal evaluation of the eyes may detect a fourth criteria: pigmented iris hamartomas (Lisch nodules). The remaining NIH criteria include optic path glioma, distinctive osseus lesions, and a positive family history of the condition. A breast cancer 2 (BRCA2) positive woman with NF1 and chronic lymphocytic leukemia is described. Patients with NF1 have an increased lifetime risk to develop breast cancer, gastrointestinal stromal tumor, malignant glioma, malignant peripheral nerve sheath tumor, and rhabdomyosarcoma. Chronic lymphocytic leukemia occurring in NF1 patients is rare; including my female patient reported in this paper, chronic lymphocytic leukemia has only been reported in three individuals with NF1--two women and one man. The man and the other woman presented with advanced chronic lymphocytic leukemia and treatment with antineoplastic therapy at diagnosis; the man achieved clinical remission and the woman passed away from complications associated with therapy-refractory progression of her leukemia. My female patient required treatment 41 months after diagnosis and had a good clinical response; she has been without significant disease progression for 34 months. Similar to NF1, breast cancer 1 (BRCA1) and BRCA2 mutations are associated with an increased lifetime risk of developing cancer--particularly breast and ovarian carcinoma. An increased risk of chronic lymphocytic leukemia has also been demonstrated in patients with mutations of either BRCA1 or BRCA2. Also, albeit uncommon, either BRCA1 or BRCA2 mutation has been detected in women with NF1 who develop breast cancer. In conclusion, the development of chronic lymphocytic leukemia in NF1 patients may be coincidental and not associated with the underlying genodermatosis; however, the occurrence of chronic lymphocytic leukemia in my patient with NF1, in part, may be related to her BRCA2 positivity.

Multiple Xanthogranulomas in an Adult Patient with Myelodysplastic Syndrome

Adult multiple xanthogranuloma (XG) is a rare late-onset variant of juvenile XG. It is characterized by the appearance of papules or nodules located preferably on the trunk. A case of a 54-year-old man with myelodysplastic syndrome is presented as a history of interest, who consulted due to the appearance of multiple brownish papules distributed mainly in the trunk. So far, there are only 22 cases of this clinical form reported in the literature, 9 of them associated with malignant hematological processes. We highlight the importance of this entity as a possible cutaneous marker of blood dyscrasias.

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.

Solitary juvenile xanthogranuloma of the hypopharynx. Clinico-pathologic study in a child with β-Thalassemia Major and Cutaneous Mastocytosis

Juvenile Xanthogranuloma (JXG), the most common pediatric non-Langerhans cell histiocytosis, may rarely occur in association with Neurofibromatosis (types 1 and 2), Juvenile Myelomonocytic Leukemia and Cutaneous Mastocytosis (CM) and, morphologically, mimics Erdheim-Chester Disease tissue lesions and ALK-positive histiocytosis. We describe a 4-year-old girl with Beta-Thalassemia Major who developed an hypopharyngeal BRAFV600E- and ALK-negative JXG and CM. JXG has been rarely reported in the aerodigestive tract and in association with CM. In this molecular era, knowledge of genetic heterogeneity of JXG and clinical scenarios in which it may develop is essential for the appropriate diagnosis and treatment of each individual patient.

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.

Advanced pharmacological therapies for neurofibromatosis type 1-related tumors

Neurofibromatosis Type 1 (NF1) is an autosomal dominant tumor-predisposition disorder that is caused by a heterozygous loss of function variant in the NF1 gene, which encodes a protein called neurofibromin. The absence of neurofibromin causes increased activity in the Rat sarcoma protein (RAS) signalling pathway, which results in an increased growth and cell proliferation. As a result, both oncological and non-oncological comorbidities contribute to a high morbidity and mortality in these patients. Optic pathways gliomas, plexiform neurofibromas and malignant peripheral nerve sheath tumor (MPNST) are the most frequent NF1-associated tumors. The treatment of these complications is often challenging, since surgery may not be feasible due to the location, size, and infiltrative nature of these tumors, and standard chemotherapy or radiotherapy are burdened by significant toxicity and risk for secondary malignancies. For these reasons, following the novel discoveries of the pathophysiological mechanisms that lead to cell proliferation and tumorigenesis in NF1 patients, emerging drugs targeting specific signalling pathways (i.e. the MEK/ERK cascade), have been developed with promising results.

[Facial manifestations of granulomatous diseases]

Clinical manifestations of granulomatous diseases are a recurring challenge in everyday dermatological practice. Clinical presentation and histological patterns are variable, depending on the particular disease. Knowledge about the differential diagnosis of granulomatous changes in the face is of decisive importance for making a rational diagnosis and therapy considering the patient's well-being. Therefore, histological and clinical characteristics of important granulomatous diseases that typically manifest on the face are presented here.

[Skin biopsy of inflammatory skin diseases in childhood-when is it reasonable?]

Compared with adulthood, inflammatory skin diseases are relatively rarely biopsied in children. Apart from the invasiveness of the procedure, the required local anesthesia, and the risks of infection and scarring, the psychological trauma of the operation has a higher impact in childhood. If a biopsy is performed, expectations towards the dermatopathology report are high. However, the evaluation of biopsies taken from children is challenging for the dermatopathologist: on the one hand, because the biopsies are often tiny or just superficial shaves and, on the other hand, because criteria for evaluation have mostly been developed from findings in adult biopsy specimens. In children, the immune system is still in the process of maturation and, therefore, infiltrates in the skin may look different from those seen in adults; however, knowledge about that is very limited to date. Moreover, numerous rare genodermatoses may manifest themselves first in childhood and need to be considered in the differential diagnosis while experience with them is often limited. Starting from the clinical presentation, this article presents histopathological features of possible differential diagnoses in order to demonstrate the value or necessity of a skin biopsy in a pediatric patient. In addition, communication with parents and child, methods of local anesthesia and biopsy techniques will be considered.

Risk of intraocular and other extracutaneous involvement in patients with cutaneous juvenile xanthogranuloma

BACKGROUND/OBJECTIVES

Cutaneous juvenile xanthogranuloma is an uncommon, usually benign disease affecting infants and young children. Ocular and other systemic involvement have been reported, but their incidence is unclear, and the utility of routine screening is not well established. Our aim was to characterize the risk of ocular and systemic complications in children with cutaneous juvenile xanthogranuloma.

METHODS

In this retrospective study, we reviewed the medical charts of children with cutaneous juvenile xanthogranuloma seen at Ann and Robert H. Lurie Children's Hospital, Chicago, Illinois, between January 2000 and December 2015. A comprehensive literature review was also performed.

RESULTS

Of 338 children with cutaneous juvenile xanthogranuloma, 76 (median age 6 months, 51% female) met inclusion criteria. The most frequently involved site was the head and neck region (40%). In 39 patients (51%), there was a single lesion. Multiple lesions (>5) were evident in 20 patients (26%). Most cutaneous juvenile xanthogranulomas were micronodular (77%). None of the patients had ocular involvement. One patient had multiple asymptomatic hepatic nodules on imaging that regressed spontaneously within several months. Literature review of pediatric cutaneous juvenile xanthogranuloma series, including our cohort, revealed that the incidence of ocular manifestations is 0.24% (7/2949) and of systemic manifestations is 0.75% (22/2949).

CONCLUSION

Cutaneous juvenile xanthogranulomas are generally limited to the skin. Because eye involvement is rare, a routine eye examination is of low yield and probably not warranted in children with no ocular or visual symptoms. New recommendations for systemic screening could not be drawn from this study.

Possible modifier genes in the variation of neurofibromatosis type 1 clinical phenotypes

Neurofibromatosis type 1 (NF1) is the most common neurogenetic disorder worldwide, caused by mutations in the (NF1) gene. Although NF1 is a single-gene disorder with autosomal-dominant inheritance, its clinical expression is highly variable and unpredictable. NF1 patients have the highest known mutation rate among all human disorders, with no clear genotype-phenotype correlations. Therefore, variations in NF1 mutations may not correlate with the variations in clinical phenotype. Indeed, for the same mutation, some NF1 patients may develop severe clinical symptoms whereas others will develop a mild phenotype. Variations in the mutant NF1 allele itself cannot account for all of the disease variability, indicating a contribution of modifier genes, environmental factors, or their combination. Considering the gene structure and the interaction of neurofibromin protein with cellular components, there are many possible candidate modifier genes. This review aims to provide an overview of the potential modifier genes contributing to NF1 clinical variability.

Mice expressing KrasG12D in hematopoietic multipotent progenitor cells develop neonatal myeloid leukemia

Juvenile myelomonocytic leukemia (JMML) is a pediatric myeloproliferative neoplasm that bears distinct characteristics associated with abnormal fetal development. JMML has been extensively modeled in mice expressing the oncogenic KrasG12D mutation. However, these models have struggled to recapitulate the defining features of JMML due to in utero lethality, nonhematopoietic expression, and the pervasive emergence of T cell acute lymphoblastic leukemia. Here, we have developed a model of JMML using mice that express KrasG12D in multipotent progenitor cells (Flt3Cre+ KrasG12D mice). These mice express KrasG12D in utero, are born at normal Mendelian ratios, develop hepatosplenomegaly, anemia, and thrombocytopenia, and succumb to a rapidly progressing and fully penetrant neonatal myeloid disease. Mutant mice have altered hematopoietic stem and progenitor cell populations in the BM and spleen that are hypersensitive to granulocyte macrophage-CSF due to hyperactive RAS/ERK signaling. Biased differentiation in these progenitors results in an expansion of neutrophils and DCs and a concomitant decrease in T lymphocytes. Flt3Cre+ KrasG12D fetal liver hematopoietic progenitors give rise to a myeloid disease upon transplantation. In summary, we describe a KrasG12D mouse model that reproducibly develops JMML-like disease. This model will prove useful for preclinical drug studies and for elucidating the developmental origins of pediatric neoplasms.