Epidemiology and geographic clustering of Erdheim-Chester disease in Italy and France.

This geoepidemiological study, performed in Italy and France, shows that Erdheim-Chester disease is increasingly diagnosed and cases cluster in specific geographic areas, namely southern Italy and central France. Disease frequency inversely correlates with the Human Development Index.

Prevalence, patterns and outcomes of cardiac involvement in Erdheim-Chester disease.

AIMS: Cardiac involvement of Erdheim-Chester disease (ECD), a rare L group histiocytosis, has been reported to be associated with poor outcomes, but systematic studies are lacking. The present study aimed to investigate the prevalence, clinical features, imaging features, and prognosis of cardiac involvement in ECD in a large series. METHODS AND RESULTS: All patients with ECD who underwent cardiac magnetic resonance (CMR) imaging between 2003 and 2019 at a French tertiary center were retrospectively included. Primary outcome was all-cause mortality. Secondary outcomes were pericarditis, cardiac tamponade, conduction disorders, device implantation and coronary artery disease (CAD). A total of 200 patients were included [63 (54-71) years, 30% female, 58% BRAFV600E mutated]. Median follow-up was 5.5 years (3.3-9 years). On CMR, right atrioventricular sulcus infiltration was observed in 37% of patients, and pericardial effusion was seen in 24% of patients. In total, 8 patients (4%) had pericarditis (7 acute, 1 constrictive), 10 patients (5%) had cardiac tamponade, 5 patients (2.5%) had ECD-related high-degree conduction disorders, and 45 patients (23%) had CAD. Overall, cardiac involvement was present in 96 patients (48%) and was associated with BRAFV600E mutation [Odds ratio (OR) = 7.4, 95% confidence interval (CI) (3.5-16.8), P < 0.001] and ECD-related clinical events [OR = 5, 95%CI (1.5-21.2), P = 0.004] but not with lower survival in multivariate analysis [adjusted hazard ratio (HR) = 1.4, 95% CI (0.8-2.5), P = 0.2]. CONCLUSION: Cardiac involvement is present in nearly half of ECD patients and is associated with BRAFV600E mutation and complications (pericarditis, cardiac tamponade, and conduction disorders) but not with lower survival.

Erdheim-Chester disease.

Erdheim-Chester disease is a rare inflammatory myeloid clonal disease which is classified into histiocytoses. It is characterized by excessive production and accumulation of foamy histiocytes and Touton giant cells in various tissues and organs. Foamy histiocytes and Touton giant cells produce proinflammatory cytokines and chemokines and contain somatic mutations in genes activating the MAPK/ERK signaling pathway, but also in genes activating the PI3K/AKT signaling pathway. BRAFV600E is the most common somatic mutation. Furthermore, somatic mutations in the MAP2K1, KRAS, NRAS, ARAF or PIK3CA genes are abundant. Erdheim-Chester dis-ease is a multisystemic disease in which any organ can be affected, especially the long bones of the lower extremities, but also the cardiovascular system, retroperitoneum, endocrine system, central nervous system, lungs, skin or orbit. The dia-gnosis is difficult because of the various manifestations of this disease. The disease occurs mainly in adults and is more common in men than in women. Targeted treatment by kinase inhibitors, interferon a, cytokine blockers or cladribine is used for the treatment.

Diagnosing a Patient with Erdheim-Chester Disease during the COVID-19 Pandemic.

Background: Erdheim-Chester disease (ECD) is a rare hematopoietic neoplasm of histiocytic origin characterized by an insidious course. The coronavirus disease 2019 (COVID-19) pandemic has put an enormous strain on healthcare systems worldwide both directly and indirectly, resulting in the disruption of healthcare services to prevent, diagnose and manage non-COVID-19 disease. Case Presentation: We describe the case of a 58-year-old male patient with sporadic episodes of self-resolving mild fever and anemia of chronic disease with onset two years before the current presentation. Positron emission/computed tomography scan revealed the presence of moderately hypermetabolic perirenal tissue masses. In order to achieve diagnosis, repeated perirenal tissue biopsies were performed, and the diagnostic evaluation was complicated by the strain put on the healthcare system by the COVID-19 pandemic. The patient contracted SARS-CoV-2 and required hospitalization, but recovered fully. No further ECD target organ involvement was documented. Treatment options were presented, but the patient chose to defer treatment for ECD. Conclusion: A high index of suspicion and multidisciplinary team collaboration is paramount to achieve diagnosis in rare conditions such as ECD. Disruptions in healthcare services in the pandemic milieu may disproportionately affect people with rare diseases and further study and effort is required to better meet their needs in the pandemic setting.

Prevalence of Hypothyroidism in Patients With Erdheim-Chester Disease.

Importance: Erdheim-Chester disease (ECD) is a rare non-Langerhans cell histiocytosis affecting multiple organs and commonly caused by somatic pathogenic variants in BRAF V600E and mitogen-activated protein kinase genes. Clinical features of ECD result from histiocytic involvement of various tissues; while endocrine involvement in ECD occurs frequently, the prevalence of central or primary hypothyroidism has not been thoroughly investigated. Objective: To assess hypothalamus-pituitary-thyroid (HPT) dysfunction in patients with ECD. Design, Setting, and Participants: This cross-sectional study included 61 patients with ECD who were enrolled in a natural history study at a tertiary care center between January 2011 and December 2018. ECD was diagnosed on the basis of clinical, genetic, and histopathological features. Data were analyzed in March 2020. Exposure: Diagnosis of ECD. Main Outcomes and Measures: Main outcome was the prevalence of thyroid dysfunction in adults with ECD compared with community estimates. Patients underwent baseline evaluation with a thyroid function test, including thyrotropin, free thyroxine (fT4), and total thyroxine (T4), and sellar imaging with magnetic resonance imaging or computed tomography scan. The association of HPT dysfunction was assessed for differences in age, sex, body mass index, BRAF V600E status, high sensitivity C-reactive protein level, sellar imaging, and pituitary hormonal dysfunction. Results: A total of 61 patients with ECD (46 [75%] men; mean [SD] age, 54.3 [10.9] years) were evaluated. Seventeen patients (28%) had hypothyroidism requiring levothyroxine therapy. The prevalence of both central and primary hypothyroidism were higher than community estimates (central hypothyroidism: 9.8% vs 0.1%; odds ratio, 109.0; 95% CI, 37.4-260.6; P < .001; primary hypothyroidism: 18.0% vs 4.7%; OR, 4.4; 95% CI, 2.1-8.7; P < .001). Patients with hypothyroidism (both primary and central), compared with patients with euthyroidism, had higher body mass index (median [interquartile range] 31.4 [28.3-38.3] vs 26.7 [24.4-31.9]; P = .004) and a higher prevalence of panhypopituitarism (7 [47%] vs 3 [7%]; P < .001). Among patients with hypothyroidism, those with central hypothyroidism, compared with patients with primary hypothyroidism, had a lower mean (SD) body mass index (28.3 [2.6] vs 36.3 [5.9]; P = .007) and higher frequencies of abnormal sellar imaging (5 [83%] vs 3 [27%]; P = .050) and panhypopituitarism (5 [83%] vs 3 [27%]; P = .050). Conclusions and Relevance: In this cohort study, a higher prevalence of central and primary hypothyroidism was identified in patients with ECD compared with the community. There should be a low threshold for testing for hypothyroidism in patients with ECD, and treatment should follow standard guidelines.

Erdheim-Chester disease: a rapidly evolving disease model.

Erdheim-Chester disease (ECD) is a rare non-Langerhans cell histiocytosis with a putative neoplastic and inflammatory nature. The disease is driven by mutations in proto-oncogenes such as BRAF and MEK, while immune-mediated mechanisms contribute to disease development and progression. The clinical presentation of ECD is highly heterogeneous, ranging from smouldering unifocal forms to multiorgan life-threatening disease. Almost any organ can be involved, but the most common lesions include long-bone involvement, retroperitoneal fibrosis, interstitial lung disease, pericardial and myocardial infiltration, CNS, retro-orbital, and large-vessel involvement. These manifestations may mimic those of neoplastic and systemic immune-mediated diseases. Overlap with these conditions represents an emerging challenge for the clinician. A variety of treatments are efficacious for ECD, targeting both the MAPK-pathway and the immune-mediated pathomechanisms. The traditional approach is based on immunomodulatory agents (interferon-α), but recent alternatives-including anti-cytokine therapies (IL1- and TNFα-blockers) and immunosuppressants (mTOR-inhibitors)-showed promising results. However, since the detection of MAPK pathway activation in most patients and the dramatic efficacy of BRAF and MEK inhibitors, these targeted treatments represent the first-line approach in patients with severe disease forms. High rates of radiologic responses do not often mean clinical remission, especially for CNS involvement, which often results in chronic disability. This review will outline the main clinical features of ECD, with emphasis on the emerging challenges in pathogenesis and management, and on the role of recent targeted approaches.

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.

Langerhans Cell Histiocytosis and Other Histiocytic Diseases of the Lung.

Several histiocytic disorders may affect the thoracic cavity. Pulmonary Langerhans cell histiocytosis (LCH) is the histiocytic disorder that most frequently manifests with thoracic involvement in adults and is associated with cigarette smoking. The histiocytic disorders follow variable clinical courses ranging from benign disease to life-threatening aggressive disorders. Although the pathogenesis is not fully understood, it is now apparent that some of these disorders are associated with activating mutations in cell proliferative/regulatory pathways. Management of these rare disorders must be individualized. Pharmacologic treatment may include the use of chemotherapeutic agents. Smoking cessation is imperative in the management of pulmonary LCH.

Uncommon histiocytic disorders: Rosai-Dorfman, juvenile xanthogranuloma, and Erdheim-Chester disease.

Rosai-Dorfman disease (RDD), juvenile xanthogranuloma (JXG), and Erdheim-Chester disease (ECD) are non-Langerhans cell (non-LCH) disorders arising from either a dendritic or a macrophage cell. RDD is a benign disorder that presents with massive lymphadenopathy, but can have extranodal involvement. In most cases, RDD is self-limited and observation is the standard approach. Treatment is restricted to patients with life-threatening, multiple-relapsing, or autoimmune-associated disease. JXG is a pediatric histiocytosis characterized by xanthomatous skin lesions that usually resolve spontaneously. In a minority of cases, systemic disease can occur and can be life threatening. Juvenile myelomonocytic leukemia (JMML), as well as germline mutations in NF1 and NF2, have been reported in children with JXG. Recent whole-exome sequencing of JXG cases did not show the BRAF-V600E mutation, although 1 patient had PI3KCD mutation. ECD is an adult histiocytosis characterized by symmetrical long bone involvement, cardiovascular infiltration, a hairy kidney, and retroperitoneal fibrosis. Central nervous system involvement is a poor prognostic factor. Interferon-α is the standard as front-line therapy, although cladribine and anakinra can be effective in a few refractory cases. More than one-half of ECD patients carry the BRAF-V600E mutation. Currently, >40 patients worldwide with multisystemic, refractory BRAF-V600E(+) ECD have been treated with vemurafenib, a BRAF inhibitor, which was found to be highly effective. Other recurrent mutations of the MAP kinase and PI3K pathways have been described in ECD. These discoveries may redefine ECD, JXG, and LCH as inflammatory myeloid neoplasms, which may lead to new targeted therapies.

Adult Orbital Xanthogranulomatous Disease: A Review with Emphasis on Etiology, Systemic Associations, Diagnostic Tools, and Treatment.

Adult orbital xanthogranulomatous diseases are rare entities and encompass a group of disorders with varying manifestations that are poorly understood. Taken as a group, there are non-Langerhans histiocytic disorders (type II) that are diagnosed histologically by the presence of foamy histiocytes, Touton giant cells, and varying degrees of fibrosis. Based on the accompanying systemic associations, there are 4 main categories of adult xanthogranulomatous disease: adult-onset xanthogranuloma, adult-onset asthma and periocular xanthogranuloma, necrobiotic xanthogranuloma, and Erdheim-Chester disease. Herein, we discuss the etiopathogenesis, systemic associations, methods of diagnosis, and treatment options for these disorders.

Enfermedad de Erdheim-Chester: estudio de 12 casos / Erdheim-Chester disease: study of 12 cases

Fundamento y objetivo: La enfermedad de Erdheim-Chester (EC) es una histiocitosis de células no-Langerhans que cursa con infiltración xantogranulomatosa multiorgánica por histiocitos CD68+/CD1a-. Se recogen las principales características de 12 pacientes diagnosticados de esta rara enfermedad. Pacientes y método: Se revisaron las historias clínicas y los hallazgos anatomopatológicos de 12 casos diagnosticados de enfermedad de EC en 7 hospitales terciarios de la península. Se consideró el diagnóstico de esta enfermedad ante un cuadro clínico compatible e infiltración tisular por histiocitos CD68+/CD1a-. Resultados: Se incluyó en el estudio a 12 pacientes, 7 varones, con una mediana de seguimiento de 36 meses (rango IQ: 20-84). La mediana de edad al inicio clínico de la enfermedad y en el momento del diagnóstico histológico fue de 49 (rango IQ: 28-61) y 56 años (37-62), respectivamente. En 6 casos se realizaron múltiples biopsias para poder llegar al diagnóstico, mientras que en 3 fue la revisión de las mismas piezas anatomopatológicas en un adecuado contexto de sospecha clínica lo que permitió el diagnóstico. Las manifestaciones neurológicas presentaron una asociación estadísticamente significativa con la mortalidad (p<0,05). La característica afectación ósea en forma de osteoesclerosis metadiafisaria de huesos largos se detectó en 9 casos. Conclusiones: La enfermedad de EC presenta una gran heterogeneidad en sus manifestaciones clínicas. Es preciso un alto índice de sospecha y una estrecha colaboración entre clínicos y patólogos para llegar al diagnóstico de esta enfermedad (AU)

Background and objective: Erdheim-Chester disease (EC) is a rare form of non-Langerhans’ cell histiocytosis. It is characterized by the xanthomatous infiltration of tissues with foamy CD68+/CD1a- histiocytes. We report a series of 12 patients diagnosed with EC.Patients and methods: We reviewed the clinical, pathological and therapeutic aspects of 12 cases diagnosed with EC at 7 tertiary teaching hospitals in Spain. Patients were included if tissue infiltration by histiocytes CD68+/CD1a- could be demonstrated in an appropriate clinical setting. Results: Twelve patients (7 male) were included. Median follow-up was 36 months (IQR: 20-84). The median age at the time of clinical onset and pathological diagnosis was 49 (IQR: 28-61) and 56 years (IQR: 37-62), respectively. In 6 cases multiples biopsies were performed (skin, muscle, testicular) previous to diagnosis, which was confirmed in 3 cases after a carefully review of pathological tissues. Neurological involvement was independently associated with mortality (P<.05). Characteristic long bone osteosclerosis was detected in 9 patients. Conclusion: EC is a multisystemic and heterogeneous clinicopathological condition. A high index of suspicion and fluent communication between clinicians and pathologists is necessary to achieve a correct diagnosis (AU)

High prevalence of BRAF V600E mutations in Erdheim-Chester disease but not in other non-Langerhans cell histiocytoses.

Histiocytoses are rare disorders of unknown origin with highly heterogeneous prognosis. BRAF mutations have been observed in Langerhans cell histiocytosis (LCH). We investigated the frequency of BRAF mutations in several types of histiocytoses. Histology from 127 patients with histiocytoses were reviewed. Detection of BRAF(V600) mutations was performed by pyrosequencing of DNA extracted from paraffin embedded samples. Diagnoses of Erdheim-Chester disease (ECD), LCH, Rosai-Dorfman disease, juvenile xanthogranuloma, histiocytic sarcoma, xanthoma disseminatum, interdigitating dendritic cell sarcoma, and necrobiotic xanthogranuloma were performed in 46, 39, 23, 12, 3, 2, 1, and 1 patients, respectively. BRAF status was obtained in 93 cases. BRAF(V600E) mutations were detected in 13 of 24 (54%) ECD, 11 of 29 (38%) LCH, and none of the other histiocytoses. Four patients with ECD died of disease. The high frequency of BRAF(V600E) in LCH and ECD suggests a common origin of these diseases. Treatment with vemurafenib should be investigated in patients with malignant BRAF(V600E) histiocytosis.

[Intraocular involvement in Erdheim-Chester disease--first report in the literature: case report]. / Acometimento intra-ocular na doença de Erdheim-Chester--primeiro relato na literatura: relato de caso.

Erdheim-Chester disease (ECD) is a granulomatous and infiltrative disorder of unknown etiology with proliferation of cholesterol-containing histiocytes and peculiar bone involvement. It is very similar to Langerhans cell histiocytosis (LCH) on histology but with a different immunohistochemical profile. This is the first report of intraocular involvement in this disease. MPSG, a 46 y.o. woman, presented with proptosis of the OD. She referred ulcerated lesions on the hard palate, symmetrical and bilateral osteosclerosis of the fibulae and tibiae and a nodule in the right breast (biopsy: xantomatous histiocytic infiltrate CD68+, S-100 and CD1a negative on immunohistochemistry compatible with ECD). MRI studies demonstrated an extraconal tumor in the juxta-bulbar temporal portion of the right orbit close to the lacrimal gland and hyperintense on T1. Vision was 20/20 OU, with numerous drusen in the posterior pole, similar to basal laminar drusen. Two regions of orange subretinal infiltrates that showed progressive staining on the angiogram were seen in the peripapillary region and also close to the fovea in the OD. Choroidal neovascular membranes were seen 2 years later in OU leading to severe visual loss in the OS and to a slight visual field loss in the OD, which retained 20/20 vision. This pioneer report depicts in vivo characteristics of histiocytic granulomas in ECD. Caution should be taken with patients with ECD as potentially blinding intraocular complications may arise.

Acometimento intra-ocular na doença de Erdheim-Chester - primeiro relato na literatura: relato de caso / Intraocular involvement in Erdheim-Chester disease - first report in the literature: case report

A doença de Erdheim-Chester (DEC) tem causa desconhecida e se caracteriza por ser granulomatosa e infiltrativa, com proliferação de histiócitos contendo colesterol e particular acometimento ósseo. À histologia, é semelhante à histiocitose de células Langerhans, salvo na análise imuno-histoquímica. Pela primeira vez é descrito o acometimento intra-ocular nesta doença. MPSG, 46 anos, sexo feminino, apresentou-se com proptose do olho direto. Referia úlceras no palato duro, osteoesclerose bilateral e simétrica na diáfise tibial e fibular e nódulo na mama direita (biópsia: infiltrado rico em histiócitos xantomatosos e perfil imuno-histoquímico com CD68 +, S-100 e CD1a negativos, compatível com DEC). À RNM, tumoração extraconal justa-bulbar temporal superior na órbita direita, hiperintensa em T1 e próxima da glândula lacrimal. Em cada olho, visão 20/20, com numerosas drusas nas arcadas e na região macular similares às drusas laminares basais, além de duas regiões placóides elevadas com infiltrado alaranjado sub-retiniano e hiperfluorescentes na angiografia na região peridiscal inferior e justamacular temporal do olho direito. Dois anos depois, surgiram membranas neovasculares sub-retinianas em ambos os olhos. O OD manteve visão 20/20 com pequenas alterações campimétricas e o OE evoluiu com grande cicatriz disciforme e visão de vultos. Esta descrição pioneira demonstra características in vivo dos granulomas histiocíticos da DEC, e alerta para possíveis complicações intra-oculares.

Erdheim-Chester disease (ECD) is a granulomatous and infiltrative disorder of unknown etiology with proliferation of cholesterol-containing histiocytes and peculiar bone involvement. It is very similar to Langerhans cell histiocytosis (LCH) on histology but with a different immunohistochemical profile. This is the first report of intraocular involvement in this disease. MPSG, a 46 y.o. woman, presented with proptosis of the OD. She referred ulcerated lesions on the hard palate, symmetrical and bilateral osteosclerosis of the fibulae and tibiae and a nodule in the right breast (biopsy: xantomatous histiocytic infiltrate CD68+, S-100 and CD1a negative on immunohistochemistry compatible with ECD). MRI studies demonstrated an extraconal tumor in the juxta-bulbar temporal portion of the right orbit close to the lacrimal gland and hyperintense on T1. Vision was 20/20 OU, with numerous drusen in the posterior pole, similar to basal laminar drusen. Two regions of orange subretinal infiltrates that showed progressive staining on the angiogram were seen in the peripapillary region and also close to the fovea in the OD. Choroidal neovascular membranes were seen 2 years later in OU leading to severe visual loss in the OS and to a slight visual field loss in the OD, which retained 20/20 vision. This pioneer report depicts in vivo characteristics of histiocytic granulomas in ECD. Caution should be taken with patients with ECD as potentially blinding intraocular complications may arise.

[Erdheim-Chester disease: a non-Langerhans cell histiocytosis. A clinical-case and review of the literature]. / La malattia di Erdheim-Chester una istiocitosi a cellule non Langerhans. Rewiew della letteratura e descrizione di un caso clinico.

We make a retrospective evaluation of clinical and radiologic features, treatment, and outcome of Erdheim-Chester disease, a rare non-Langerhans cell histiocytosis. We report a case of Erdheim-Chester disease and review 60 cases from the literature. These cases are consider to have Erdheim-Chester disease when they have either typical bone radiographs (symmetrical long bones osteosclerosis) and/or histologic criteria disclosing histiocytic infiltration with distinctive immunohistochemical phenotype of the non-Langerhans cell histiocytes with positive staining for CD68 and negative staining for S-100 protein and CD1a. Our patient undergoes chemiotherapy according to the LCH-II stratification and therapy plan (Vinblastine, Etoposide and Prednisone) and thereafter receives Carboplatin and Etoposide, and Somatostatin. She is alive and clinically well 33 months after onset of symptoms and the lesions don't appear to progress at imaging examinations. In conclusion, Erdheim-Chester disease may be confused with Langerhans cell histiocytosis as it sometimes shares the same clinical (exophthalmos, diabetes insipidus) or radiologic (osteolytic lesions) findings. However, the characteristics radiological pattern of Erdheim-Chester disease together the immunohistochemical phenotype of hystiocytic infiltration supports the theory that Erdheim-Chester disease is a unique disease entity distinct.