Imaging in Erdheim-Chester Disease.

Erdheim-Chester disease (ECD) is a rare, multisystemic, inflammatory, non-Langerhans cell histiocytic neoplasm. The discovery of recurrent and somatic mutations in the mitogen-activated protein kinase signaling pathway, most commonly BRAFV600E, has led to a reclassification of ECD from an inflammatory disorder to a neoplastic process. It is now included in the revised 2016 World Health Organization classification of hematopoietic tumors and in the Langerhans group in the revised 2016 Histiocytosis Classification of the Histiocyte Society. When symptomatic, ECD most commonly manifests with bone pain and fatigue. Also, neurologic manifestations, central diabetes insipidus, exophthalmos, and periorbital xanthelasma-like lesions are frequently encountered. Pathologic findings may vary depending on the site of biopsy and may display a spectrum of features. Thus, due to the diverse clinical presentation and variable histologic findings, imaging can often show the first sign of the disease. Radiologic findings are, however, interpreted in conjunction with clinical and histologic findings to establish the diagnosis of ECD. From providing classic findings that facilitate diagnosis to helping radiologists determine the extent of disease and predicting a prognosis, the role of radiology in ECD has evolved with the understanding of the disease itself. Insights into the molecular pathogenesis and the development of targeted therapeutic agents along with approval of vemurafenib and cobimetinib have necessitated revision of the guidelines for the management of ECD. The authors discuss various radiologic findings of ECD and differential diagnoses by using an organ system-based approach and briefly describe the revised consensus recommendations for evaluation, diagnosis, and treatment based on the International Medical Symposia on ECD from a radiologist's perspective. ©RSNA, 2024 Supplemental material is available for this article. The full digital presentation is available online.

Cardiovascular manifestations of Erdheim-Chester disease: A narrative review with two cases.

Erdheim-Chester disease (ECD) is a rare 'L' (Langerhans) group histiocytic neoplasm that affects a multitude of organ systems, causing osteosclerotic bone lesions, periaortic encasement ('coated' aorta), retroperitoneal fibrosis involving kidneys and ureters ('hairy kidney'), and infiltration of the central nervous system. Cardiovascular involvement can occur in up to 70% of patients and is usually found during computed tomography/magnetic resonance imaging evaluation. When present, cardiovascular symptoms can have wide variability in presentation from asymptomatic to pericarditis, fatal cardiac tamponade, myocardial infarction, conduction abnormalities, heart failure, renal artery stenosis, and claudication. Cardiac involvement found on imaging includes right atrial pseudotumor, right atrioventricular groove infiltration, and pericardial effusions. ECD can involve the large- and medium-sized arteries, often seen as periarterial thickening (commonly coating the aorta) with stenosis/occlusion. Although more cardiovascular ECD cases have begun to be published in the literature, more data are needed on the outcomes of these patients, as well as how cardiovascular manifestations respond to treatment of ECD.

Erdheim-Chester Disease Occult on Radiographs and CT but Visible on MRI and PET.

BACKGROUND Erdheim-Chester disease (ECD) is a rare neoplasm of histiocytes that is characterized by prominent involvement of the long bones. Approximately 1500 cases have been reported since the disease was first described in 1930. The imaging appearance of ECD can be highly variable given the numerous systems it can affect. In this case report we discuss a patient whose ECD was occult on multiple imaging modalities. CASE REPORT We report the case of a 60-year-old woman who presented with sub-acute left knee and calf pain that led to an MRI. She was found to have innumerable marrow-replacing lesions in the axial and appendicular skeleton visualized on the initial MRI, as well as on an ¹8F-FDG PET/CT scan. The patient did not have extraosseous abnormal uptake on the PET/CT. Subsequently, a lesion from the left iliac bone was histologically confirmed as ECD on the basis of positive staining for CD68 and CD163 and negative staining for CD1a. Osseous lesions in ECD have a distinct imaging appearance and are typically detected by radiography and bone scintigraphy, among other modalities; however, the lesions in this case were unexpectedly absent from those studies. CONCLUSIONS If there is a high degree of suspicion for ECD, 18F-FDG PET/CT and/or MRI may be necessary for adequate visualization of bone lesions, given that those lesions can have an infiltrative nature that may be difficult to image with other anatomic imaging modalities. Use of 18F-FDG PET/CT and/or MRI may also lead to adequate guidance of confirmatory biopsy.

Typical Bone Scintigraphy Presentation of Erdheim-Chester Disease in a Patient Diagnosed With IgG4-Related Disease.

ABSTRACT: A 50-year-old woman presented a dry syndrome, joint pain, inflammatory syndrome, polyclonal hypergammaglobulinemia, and tubulointerstitial nephritis. Imaging studies (including FDG PET/CT) revealed infrarenal retroperitoneal fibrosis with periaortitis and hypermetabolic osteosclerotic lesions. Bone scintigraphy demonstrated intense uptake in the femoral, tibial, and radial regions, suggestive of non-Langerhans histiocytosis, specifically Erdheim-Chester disease. A bone biopsy confirmed the presence of IgG4-positive plasma cells but no histiocytes. The patient received corticosteroid therapy followed by rituximab, resulting in a complete response. This case suggests an atypical manifestation of bone lesions in IgG4-related disease, emphasizing the diagnostic challenge between IgG4-related disease and Erdheim-Chester disease.

Multiple Nervous System Involvement of Erdheim-Chester Disease With Responsive Perinephritic Hypermetabolism.

ABSTRACT: A 36-year-old man who was at follow-up for histiocytosis had sudden-onset symptoms of unilateral ophthalmic increased pressure. The patient was referred to the FDG PET/CT for determination of involvement with suspicion of Erdheim-Chester disease. The reduction of the FDG uptake in all of the lesions (medial temporal lobes, nasal septum, medulla spinalis in sacral region, as well as perinephritic infiltrations), which were determined by the first PET/CT, was achieved at second imaging.

El papel de la PET/TC con 2-[18F]FDG en la enfermedad de Erdheim-Chester / The role of 2-[18F]FDG PET/CT in Erdheim-Chester disease

Objetivo Analizar la distribución corporal de la enfermedad Erdheim-Chester (ECD) y determinar la utilidad de la 2-[18F]FDG-PET/TC frente a otras técnicas de imagen. Asimismo, evaluar la agresividad y la extensión de la enfermedad según la presencia/ausencia de mutación BRAFV600E. Material y métodos Se revisaron las 2-[18F]FDG-PET/TC de todos los pacientes diagnosticados con ECD entre 2008 y 2021: en total, 19 pacientes. Los territorios afectados se clasificaron como detectables por PET/TC o detectables solamente por otras técnicas de imagen (gammagrafía ósea, TC con contraste yodado o RM). Se realizó análisis descriptivo y correlación de la mutación BRAF con los órganos afectados y SUVmáx mediante la prueba t de Student. Resultados De los 19 pacientes (14 hombres; edad media 60,3años), 11 presentaban la mutación BRAFV600E. Se detectaron un total de 127 territorios (64 órgano-sistemas) afectados utilizando las diferentes modalidades de imagen, de los cuales 112 fueron detectados por la PET/TC y 15 territorios adicionales fueron identificados únicamente por la RM cerebral y cardiaca. La presencia de mutación BRAFV600E se asoció con mayor afectación orgánica (p<0,05), sin diferencias en el SUVmáx (p>0,05). Conclusión La 2-[18F]FDG-PET/TC es una prueba de alto rendimiento diagnóstico en pacientes con ECD, detectando la mayoría de los territorios afectados. La RM fue la única prueba de imagen con hallazgos adicionales en territorios con alta captación fisiológica de 2-[18F]FDG (cerebral y cardíaca). La presencia de mutación del BRAFV600E se correlacionó con mayor extensión de la enfermedad (AU)

Objective To analyze the body distribution of Erdheim-Chester disease (ECD) and determine the utility of 2-[18F]FDG PET/CT compared to other imaging techniques. Additionally, to assess the aggressiveness and extent of the disease based on the presence/absence of the BRAFV600E mutation. Materials and methods The 2-[18F]FDG PET/CT scans of all patients diagnosed with ECD between 2008 and 2021 were reviewed, including 19 patients. The affected territories were classified as detectable by PET/CT or detectable only by other imaging techniques (bone scintigraphy, contrast-enhanced CT, or MRI). Descriptive analysis and correlation of the BRAF mutation with the affected organs and maximum SUV were performed using the Student's t-test. Results Out of the 19 patients (14 males; mean age 60.3years), 11 had the BRAFV600E mutation. A total of 127 territories (64 organ-systems) affected were identified using different imaging modalities, of which 112 were detected by PET/CT, and an additional 15 territories were solely identified by cerebral and cardiac MRI. The presence of BRAFV600E mutation was associated with greater organ involvement (P<.05) without differences in SUVmax (P>.05). Conclusion 2-[18F]FDG PET/CT is a highly effective diagnostic tool in patients with ECD, detecting the majority of affected territories. MRI was the only imaging modality with additional findings in territories showing high physiological uptake of 2-[18F]FDG (cerebral and cardiac). The presence of the BRAFV600E mutation correlated with a higher extent of the disease (AU)

Rare Onset of Erdheim-Chester Disease in Children and Young Adults: A Case Series and Review of the Literature.

INTRODUCTION: Erdheim-Chester disease (ECD) is a rare histiocytic neoplasm that affects patients, predominantly males aged 40-70 years, with very heterogeneous clinical presentation and prognosis. In 2020, Goyal et al. proposed consensus recommendations for the management of patients with ECD, remarking on the exceptional presentation of the disease in the pediatric population. CASE PRESENTATION: The first patient, a 20-year-old male, underwent cervical laminectomy and partial removal of a cervical spine lesion, initially apparently consistent with cervical schwannomas. The second patient, a 9-year-old female, received surgery for an extra-axial lesion of the greater sphenoid wing, radiologically consistent with a meningioma. CONCLUSION: At present, 15 pediatric cases have been reported in the literature with involvement of the central nervous system, with no consensus on the diagnostic and therapeutic management, as Pegoraro et al. evidenced in their pediatric multicenter case series. The present article adds two new cases of ECD with onset in childhood and young adulthood, who received the diagnosis after neurosurgical procedures.

Erdheim-Chester disease of brain parenchyma without any systemic involvement: A case report and review of literature.

Erdheim-Chester disease is a non-Langerhans cell histiocytosis syndrome characterised by histiocytic infiltration of different organs and systems in the body. Erdheim-Chester disease with isolated central nervous system (CNS) involvement causes diagnostic difficulties due to the absence of systemic findings and may result in misdiagnosis and inaccurate treatment choices. The case discussed in this report exemplifies how challenging it is to diagnose Erdheim-Chester disease with isolated CNS involvement. This case, which presented with progressive pyramidocerebellar syndrome, was clinically and radiologically resistant to all immunosuppressive and immunomodulatory treatments administered. The presence of false negative results in repeated histopathological investigations and the absence of evidence for systemic disease hindered the diagnosis and treatment work-up. In this study, we reviewed and discussed the prominent features of the presented case in light of the relevant literature.

Erdheim-Chester disease: misdiagnosed as multiple sclerosis.

Erdheim-Chester disease is a rare histiocytic neoplasm with a wide range of clinical manifestations. Due to its rarity and protean characteristics, this condition often presents a diagnostic challenge. A Caucasian woman in her late 60s presented with unsteadiness, dysphagia and dysarthria. She was initially diagnosed with secondary progressive multiple sclerosis but deteriorated over 2 years with a potential lack of therapeutic response. Subsequent investigations resulted in the diagnosis of Erdheim-Chester disease. She received targeted therapy with BRAF and MAPK-pathway inhibitors. Her initial response to treatment has been positive with functional gains and reduced disease burden on MR brain imaging, and with no significant adverse effects.

The role of 2-[18F]FDG PET/CT in Erdheim-Chester disease.

OBJECTIVE: To analyze the body distribution of Erdheim-Chester disease (ECD) and determine the utility of 2-[18 F]FDG PET/CT compared to other imaging techniques. Additionally, to assess the aggressiveness and extent of the disease based on the presence/absence of the BRAFV600E mutation. MATERIALS AND METHODS: The 2-[18F]FDG-PET/CT scans of all patients diagnosed with ECD between 2008 and 2021 were reviewed, including 19 patients. The affected territories were classified as detectable by PET/CT or detectable only by other imaging techniques (bone scintigraphy, contrast-enhanced CT, or MRI). Descriptive analysis and correlation of the BRAF mutation with the affected organs and maximum SUV were performed using the Student's t-test. RESULTS: Out of the 19 patients (14 males; mean age 60.3 years), 11 had the BRAFV600E mutation. A total of 127 territories (64 organ-systems) affected were identified using different imaging modalities, of which 112 were detected by PET/CT, and an additional 15 territories were solely identified by cerebral and cardiac MRI. The presence of BRAFV600E mutation was associated with greater organ involvement (p < 0.05) without differences in SUVmax (p > 0.05). CONCLUSION: 2-[18F]FDG PET/CT is a highly effective diagnostic tool in patients with ECD, detecting the majority of affected territories. MRI was the only imaging modality with additional findings in territories showing high physiological uptake of 2-[18F]FDG (cerebral and cardiac). The presence of the BRAFV600E mutation correlated with a higher extent of the disease.

Skeletal involvement in Erdheim-Chester disease: Multimodality imaging features and association with the BRAFV600E mutation.

OBJECTIVE: The aim of this study was to characterize the distribution of skeletal involvement in Erdheim-Chester disease (ECD) by using radiography, computed tomography (CT), 18F-FDG positron emission tomography/computed tomography (PET/CT), and bone scans, as well as looking for associations with the BRAFV600E mutation. MATERIAL AND METHODS: Prospective study of 50 consecutive patients with biopsy-confirmed ECD who had radiographs, CT, 18F-FDG PET/CT, and Tc-99m MDP bone scans. At least two experienced radiologists with expertise in the relevant imaging studies analyzed the images. Summary statistics were expressed as the frequency with percentages for categorical data. Fisher's exact test, as well as odds ratios (OR) with 95 % confidence intervals (CI), were used to link imaging findings to BRAFV600E mutation. The probability for co-occurrence of bone involvement at different locations was calculated and graphed as a heat map. RESULTS: All 50 cases revealed skeletal involvement at different regions of the skeleton. The BRAFV600E mutation, which was found in 24 patients, was correlated with femoral and tibial involvement on 18F-FDG PET/CT and bone scan. The appearance of changes on the femoral, tibial, fibular, and humeral involvement showed correlation with each other based on heat maps of skeletal involvement on CT. CONCLUSION: This study reports the distribution of skeletal involvement in a cohort of patients with ECD. CT is able to detect the majority of ECD skeletal involvement. Considering the complementary nature of information from different modalities, imaging of ECD skeletal involvement is optimized by using a multi-modality strategy.

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.

Esclerosis bilateral de huesos largos: enfermedad de Erdheim-Chester. Reporte de un caso / Bilateral long bone sclerosis: Erdheim-Chester disease. Case report

La enfermedad de Erdheim-Chester (EEC) es una patología poco frecuente, caracterizada por presentar infiltración xantogranulomatosa sistémica, con afección de diversos sistemas incluido el óseo. La EEC se encuentra descripta dentro de las enfermedades osteocon-densantes (EO), las cuales se reconocen por presentar aumento de la masa ósea y compromiso tanto de huesos largos como planos. La presentación clínica de la EEC es variada: puede presentar desde un curso indolente hasta manifestaciones multisistémicas. Las características radiológicas son de gran importancia para establecer su diagnóstico. Presentamos una paciente con EEC, con esclerosis bilateral de huesos largos, que exhibe algunas características diferenciales con relación a otros casos reportados: a) afectación exclusivamente ósea a 10 años de evolución, b) compromiso bilateral y simétrico de distinta magnitud, c) esclerosis cortical endóstica y perióstica, d) signos radiológicos sugestivos de periostitis, d) ausencia de compromiso metafisario, e) ausencia de actividad metabólica de las lesiones en las imágenes de 18F-FDG PET/CT.Conclusión: la presencia de lesiones osteocondensantes bilaterales exclusivamente en huesos largos deben hacer sospechar EEC. La ausencia de compromiso metafisario y de actividad metabólica en 18F-FDG PET/CT ha sido raramente descripta. (AU)

Erdheim - Chester disease (ECD) is a rare disease, characterized by systemic xanthogranulomatous infiltration, with involvement of various organs including bone. ECD is described within the sclerosing bone disorders, which are recognized for presenting increased bone mass and involvement of both long and flat bones. The clinical presentation of ECD is diverse, ranging from an asymptomatic course to multisystemic manifestations. Radiological features are of great importance to establish the diagnosis. We describe here a patient with ECD, with bilateral sclerosis of long bones that presents some differential characteristics in relation to other reported cases: a) exclusively bone involvement at 10 years of evolution, b) bilateral and symmetric involvement of different magnitude, c) endosteal and periosteal cortical sclerosis d) radiological signs suggestive of periostitis, d) absence of metaphyseal involvement, e) absence of metabolic activity of the lesions in 18F-FDG PET/CT.Conclusion: the presence of bilateral osteosclerosis exclusively in long bones should lead to suspect ECD. The absence of metaphyseal involvement and metabolic activity in 18F-FDG PET/CT have been rarely described. (AU)