Histiocytic Disorders of Childhood.

Histiocytic disorders of childhood represent a wide spectrum of conditions that share the common histologic feature of activated or transformed "histiocytes." Langerhans cell histiocytosis (LCH) is the most common, with an incidence of approximately 5 per million children. LCH may be difficult to distinguish from more ubiquitous causes of skin rashes, bone pain, or fever. Current chemotherapy fails to cure more than 50% of children with multifocal disease, and treatment failure is associated with increased risks of long-term sequelae. Somatic activating mitogen-activated protein kinase (MAPK) pathway-activating mutations (most often BRAFV600E) have been identified in hematopoietic precursors in patients with LCH. Opportunities to improve outcomes with targeted therapies are under investigation. Juvenile xanthogranuloma (JXG) and Rosai-Dorfman disease (RDD) are less common than LCH and are distinguished by specific histologic and clinical features. Recurrent MAPK pathway gene mutations are also identified in JXG and RDD. In many cases, these conditions spontaneously resolve, but disseminated disease can be fatal. Although there has been historic debate regarding the nature of these conditions as inflammatory versus neoplastic, LCH, JXG, and RDD are now considered myeloid neoplastic disorders. In contrast, hemophagocytic lymphohistiocytosis (HLH) is clearly a disorder of immune dysregulation. HLH is characterized by extreme immune activation driven by hyperactivated T cells. HLH arises in approximately 1 child per million and is nearly universally fatal without prompt recognition and immune suppression. Outcomes of treated children are poor, with approximately 60% survival. Emapalumab, which targets interferon-γ signaling, was recently approved for patients with recurrent or refractory HLH, and additional cytokine-directed therapies are under investigation.

Xantogranuloma juvenil: una entidad con amplio espectro clínico / Juvenile Xanthogranuloma: An Entity With a Wide Clinical Spectrum

El xantogranuloma juvenil es un trastorno benigno poco frecuente, que pertenece al amplio grupo de las histiocitosis de células no Langerhans. Se presenta con uno o más nódulos eritematosos o amarillentos, ubicados preferentemente en la cabeza y el cuello. La mayoría de los casos se inician durante el primer año de vida, incluyendo lesiones congénitas. La afectación extracutánea es rara, sugiriéndose tradicionalmente en la literatura estudiar el compromiso ocular. El diagnóstico del xantogranuloma juvenil es fundamentalmente clínico, sin embargo, en ocasiones se requiere confirmarlo con biopsia de piel. Las lesiones cutáneas son autolimitadas, por lo que suelen no requerir tratamiento. En la presente revisión se describen los distintos aspectos clínicos y terapéuticos de esta enfermedad, resaltando la evidencia respecto al estudio diagnóstico del compromiso extracutáneo

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

Successful Salvage Treosulfan-Based Megachemotherapy With Allogeneic Stem Cell Transplantation in Nonsyndromic, Therapy-Resistant Disseminated Juvenile Xanthogranuloma: A Case Report.

Juvenile xanthogranuloma (JXG) is a rare histiocytic disorder classified as non-Langerhans cell histiocytosis; although it is usually a benign and self-limiting disease, it can be fatal in some cases, especially with systemic dissemination. We present a case report of a boy with therapy-resistant disseminated JXG who was treated with systemic chemotherapy and received 3 allogeneic hematopoietic stem cell transplantations (allo-HSCTs) from an unrelated donor. The post-transplant period was complicated by acute graft vs host disease and lymphoproliferative disease caused by Epstein-Barr virus. Currently, almost 7.5 years after the first transplantation, the boy is in complete remission with full donor chimerism and without symptoms of JXG. The presented data confirm rare observations that allo-HSCT can lead to durable remission of systemic JXG, which warrants its use in life-threatening, therapy-resistant subtypes of disease.

[Successful unrelated cord blood transplantation for extensive meningeal juvenile xanthogranuloma developing after treatment of Langerhans cell histiocytosis in a child].

A 2-year and 4-month-old boy developed Langerhans cell histiocytosis (LCH) at the left parietal region of the skull. After treatment with chemotherapy, the patient achieved remission but experienced three relapses. After 3 years, he complained of headache, blurred vision, and lethargy. Brain magnetic resonance imaging revealed multiple dura-based meningeal masses. Biopsy was performed, and the patient was then diagnosed with juvenile xanthogranuloma (JXG). The analysis of both LCH/JXG tissues revealed BRAF V600E mutation. The JXG masses were not responsive to prednisolone, which was injected locally, radiotherapy (24 Gy), and chemotherapy (2-chlorodeoxy-adenosine). In addition, since the patient developed macrophage activation syndrome associated with systemic JXG progression, he received unrelated cord blood transplantation (u-CBT) at the age of 10 years and 11 months. Engraftment was performed at day 42, and significant GVHD was not observed. Four months after CBT, the patient was treated with infliximab (Remicade®) and dexamethasone palmitate (Limethasone®). The size of the intracranial JXG masses gradually decreased after u-CBT and disappeared after 4 years. Currently, the patient is doing well at the age of 25 years and is receiving androgen replacement therapy.

Long-term outcomes of children with extracutaneous juvenile xanthogranulomas in Japan.

BACKGROUND: Juvenile xanthogranuloma (JXG) is the most common non-Langerhans cell histiocytosis in children. The mortality and morbidity of JXG with extracutaneous lesions remain unclear. METHODS: Data of patients aged < 18 years who were diagnosed with JXG between 2001 and 2010 were retrospectively collected through a nationwide survey. RESULTS: Twenty patients (11 male and nine female) had extracutaneous lesions. The median observation time was 10 years (range, 0-17). Six patients presented with symptoms at birth. The median age at diagnosis was 8.5 months (range, 0 month-13 years). Fifteen patients underwent treatment for JXG, including chemotherapy (n = 11), and five did not receive treatment. All patients except one survived; 17 were disease-free and two survived with disease. One newborn-onset patient with liver, spleen, and bone marrow involvement died of the disease. Permanent sequelae included central diabetes insipidus, growth hormone deficiency, and panhypopituitarism detected at diagnosis in three, one, and two patients, respectively. Four patients had visual impairment (optic nerve compression and intraocular invasion in two each), three had epilepsy, one had mental retardation, and one had a skin scar. Eight patients who had intracranial lesions were older at diagnosis, and had a higher frequency of disease-related comorbidities and permanent sequelae than those without intracranial involvement. CONCLUSIONS: Patients with extracutaneous JXG had good outcomes, although those with intracranial lesions had serious permanent sequelae. Effective and safe treatment regimens for patients with intracranial JXG need to be developed.

Therapy Response in a Pediatric Patient With Extracutaneous Juvenile Xanthogranuloma Monitored by FDG PET/CT.

Juvenile xanthogranuloma, a rare type of non-Langerhans cell histiocytosis, generally manifests as widespread skin lesions, which is often self-limited. However, when other organs are involved, its outcome can be unfavorable, and there is no clearly defined consensus regarding what is the best imaging modality in monitoring the therapy. We report here findings of a series of FDG PET/CT scans during the course of clofarabine therapy in a 12-year-old girl with extracutaneous juvenile xanthogranuloma.

Xantogranuloma juvenil gigante: acometimento palpebral difuso e simultâneo / Giant Juvenile Xanthogranuloma: diffuse and simultaneous palpebral involvement

O xantogranuloma juvenil (XGJ) é um tumor benigno e o mais comum do grupo das doenças histiocitárias proliferativas nãoLangerhans. Lesões; 2cm são consideradas XGJ gigantes, com relatos de lesões de até 18cm. Lesões oculopalpebrais podem necessitar de tratamento cirúrgico para controle de sintomas. Esse trabalho relata o caso de um menino de 8 anos que teve as 4 pálpebras acometidas por XGJ gigantes, além do terço médio. Ele foi submetido a 3 ressecções, sendo uma bastante profunda, necessitando enxerto de pele de espessura total diretamente sobre o músculo levantador da pálpebra superior. Posteriormente, 3 procedimentos de lipoenxertia foram realizados, atingindo resultado funcional e estético adequado, sem recorrência lesional.

Juvenile xanthogranuloma (JXG) is the most common benign tumor of the group of non-Langerhans histiocytic proliferative diseases. Lesions >2 cm are considered giant JXG, with reports of lesions of up to 18 cm. Oculopalpebral lesions may require surgical treatment to control symptoms. This study reports a case of an 8-year-old boy who had four eyelids and the middle third of the face affected by giant JXG. He underwent three resections, one of which was of great depth that required a full-thickness skin graft directly on the levator palpebrae superioris muscle. Subsequently, four fat-grafting procedures were performed and adequate functional and

Haploidentical stem cell transplantation with posttransplant cyclophosphamide for refractory systemic juvenile xanthogranuloma.

Juvenile xanthogranuloma (JXG) is a generally benign, self-limited histiocytic disorder, which belongs to non-Langerhans cell histiocytoses (non-LCH). However, systemic JXG can be fatal in rare cases. We present the case of an 11-year-old female with systemic JXG, who experienced repeated vertebral compression fractures and did not fully respond to systemic chemotherapy. Based on its reported efficacy in LCH, the patient underwent human leukocyte antigen-haploidentical hematopoietic stem cell transplantation (HSCT) with posttransplant cyclophosphamide. The patient did not suffer major complications and has not experienced relapse for 13 months since HSCT. HSCT may be a potential treatment option for patients with refractory non-LCH.

The various clinical spectra of juvenile xanthogranuloma: imaging for two case reports and review of the literature.

BACKGROUND: Juvenile xanthogranuloma (JXG) belongs to the heterogeneous group of non-Langerhans cell histiocytosis and is caused by an accumulation and proliferation of macrophages. In the majority of cases JXG is a disorder of early childhood presenting during the first 2 years of life. The typical presentation is a solitary reddish or yellowish skin papule or nodule with spontaneous regression and no need for treatment. CASE PRESENTATION: Two infants with an atypical presentation of JXG, one with multiple blueberry muffin rash-like skin lesions and the other with severe multi-systemic involvement, are reported. Diagnosis was established by skin biopsy including histological work-up and immunostaining, where markers for macrophages (CD68 and CD163) exhibited significant reactivity. CONCLUSION: JXG is the most common of the non-Langerhans cell histiocytosis. The typical presentation is a solitary skin lesion. The purpose of this report is to familiarize paediatricians with an unusual variant of this entity in order to facilitate early diagnosis and raise awareness for possible visceral complications and associated medical conditions.

Intradural Juvenile Xanthogranuloma with Involvement of Multiple Nerve Roots: A Case Report and Review of the Literature.

BACKGROUND: Juvenile xanthogranuloma (JXG) is a rare, non-Langerhans cell histiocytic disorder that primarily presents as multiple cutaneous lesions in young males. Solitary lesions in the spinal column are an especially rare presentation of this disease, and central nervous system involvement can portend a poor prognosis. We report an unusual case of an adult woman with an unresectable JXG of the lumbar spine. A review of the reported cases of thoracolumbar JXG and the current data regarding diagnosis and treatment are presented. CASE DESCRIPTION: A 28-year-old woman presented with back pain and worsening lower extremity pain, numbness, and weakness. Magnetic resonance imaging demonstrated an enhancing lumbar mass. However, at surgery, no discrete mass was identified. Multiple roots were grossly enlarged, and electrical stimulation identified the L4 root with the most abnormal findings. Despite an attempt at debulking, most of the mass could not be safely removed. The patient experienced incomplete improvement of the symptoms postoperatively but elected to forgo chemotherapy. The 3-month follow-up imaging study showed active lumbar spinal disease, and imaging and follow-up examinations at 27 months revealed no changes. Her symptoms were satisfactorily controlled with conservative therapy. CONCLUSIONS: JXG of the spine is a rare disease with nonspecific clinical and radiographic findings that can make it difficult to diagnose and dictates the use of immunohistochemical staining. If possible, total surgical resection will offer the best outcomes; however, other modalities such as chemotherapy can be viable alternatives or adjuvant modalities.

Solitary juvenile xanthogranuloma in the spine pretreated with neoadjuvant denosumab therapy followed by surgical resection in a 5-year-old child: case report and literature review.

PURPOSE: We present a case report that describes neoadjuvant denosumab therapy initiated in a child with a solitary giant cell-rich juvenile xanthogranuloma tumor involving the spine, and review the current literature. METHODS: A giant cell-rich histiocytic lesion involving the 11th thoracic vertebral body was identified in a healthy 5-year-old girl with persistent back and pelvic pain for several months. Imaging examinations and an open biopsy were performed to obtain a definite pathologic diagnosis. As the tumor appeared to be aggressive in nature, we administered adjuvant therapy with denosumab preoperatively and then performed a total spondylectomy. RESULTS: Histopathology confirmed that the tumor was juvenile xanthogranuloma. No tumor metastases or recurrence were detected at the 3-year follow-up, and the patient was asymptomatic. CONCLUSIONS: In giant cell-rich tumors, denosumab is occasionally used as neoadjuvant or adjuvant therapy, especially for tumors in difficult locations or with substantial soft tissue extensions. Rare adverse events in children include skin infections and disruption of calcium homeostasis. Surgical treatment is aimed at removing the tumor and relieving the symptomatic spinal cord compression. Use of denosumab as neoadjuvant therapy for juvenile xanthogranuloma involving the spine has not been reported previously.

Granulomatous diseases: Kids are not just little people.

Granulomatous diseases represent a heterogeneous group of conditions characterized by histiocytic inflammation that affect patients of any age. These diseases differ widely in their pathogenesis and include infectious and noninfectious conditions. This review focuses on noninfectious granulomatous conditions, with particular emphasis on age-related differences in the onset, epidemiology, clinical manifestations, prognosis, and age-specific management of specific granulomatous disorders. Knowledge of age-specific aspects of granulomatous conditions in adults and children improves both the extent of the diagnostic workup and the management of these patients.

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.

BRAF V600E mutation in pediatric intracranial and cranial juvenile xanthogranuloma.

Juvenile xanthogranuloma (JXG) is a cutaneous form of non-Langerhans cell histiocytosis, primarily affecting children. The lesion is presumed to originate from either macrophages or dermal dendritic cells. JXG can rarely present as an isolated intracranial lesion and, in contrast to the dismal outcome of patients with systemic disease, cranial JXG has been shown to carry a more favorable prognosis. Here, we report for the first time 3 pediatric cases of JXG with a BRAF V600E mutation, 2 with intracranial lesions and 1 with cranial lesions. Although these intracranial/cranial lesions have been referred to as JXG, they likely differ from cutaneous JXG in both the clinical features and BRAF status. It may be more appropriate to classify intracranial/cranial JXG in the same group as Langerhans cell histiocytosis and Erdheim-Chester disease, which also have a BRAF V600E mutation. Further study of BRAF status in a larger series of JXG is warranted.