Consensus guidelines for the diagnosis and clinical management of Erdheim-Chester disease

Urologic Manifestations and Hydronephrosis as Initial Presentation of Erdheim-Chester Disease: A Rare Form of Non-Langerhans Histiocytosis

Erdheim-Chester disease (ECD) is a rare non-Langerhans histiocytosis that is classified as a malignancy of myeloid progenitor cells, with only 1,000 confirmed cases in the literature so far. It often manifests as a multi-system disorder with an initial presentation predominantly in the long bones, central nervous system (CNS), and retroperitoneal space, sometimes causing urologic symptoms as a result. ECD often presents indolently and in a spectrum of different ways, making it challenging to identify and treat. We report a case of a 63-year-old female with ECD that first presented with abdominal pain and acute renal injury due to ECD-related retroperitoneal fibrosis. We also explore the literature at large around ECD, its diagnosis, pathophysiology, and advances in treatments.

Histiocytic Neoplasms, Version 2.2021, NCCN Clinical Practice Guidelines in Oncology

Histiocytic neoplasms are rare hematologic disorders accounting for less than 1% of cancers of the soft tissue and lymph nodes. Clinical presentation and prognosis of these disorders can be highly variable, leading to challenges for diagnosis and optimal management of these patients. Treatment often consists of systemic therapy, and recent studies support use of targeted therapies for patients with these disorders. Observation ("watch and wait") may be sufficient for select patients with mild disease. These NCCN Guidelines for Histiocytic Neoplasms include recommendations for diagnosis and treatment of adults with the most common histiocytic disorders: Langerhans cell histiocytosis, Erdheim-Chester disease, and Rosai-Dorfman disease.

Erdheim-Chester disease presenting as an intracardiac mass and pericardial effusion confirmed by biopsy: a case report

Background

Erdheim–Chester disease (ECD) is a rare non-Langerhans cell histiocytosis that can affect the bones, heart, lungs, brain, and other organs. Cardiovascular involvement is common in ECD and is associated with a poor prognosis. Here, we report a case of ECD presenting as an intracardiac mass and pericardial effusion confirmed by biopsy with sternotomy.

Case summary

A 54-year-old man was admitted because of dyspnoea. He was previously diagnosed with bilateral hydronephrosis and retroperitoneal fibrosis. Echocardiography revealed a large amount of pericardial effusion and echogenic mass on the right atrial (RA) side and atrioventricular (AV) groove. Cardiac magnetic resonance imaging and positron emission tomography-computed tomography (CT) revealed infiltrative mass-like lesions in the RA and AV groove. Pericardial window formation and pericardial biopsy were performed, and the pathologic results showed only pericardial fibrosis with no specific findings. Bone scan revealed increased uptake in the long bones. Considering the high probability of ECD based on the patient’s manifestations and the imaging findings, we performed a cardiac biopsy with median sternotomy despite initial insufficient pathologic results in the pericardial biopsy. The surgical findings included multiple irregular and firm masses on the cardiac wall and large vessels; after obtaining a large amount of suspicious mass, ECD accompanied with CD68 (+) and BRAF V600E mutation was confirmed.

Discussion

Erdheim–Chester disease can be associated with various forms of cardiovascular involvement. Considering the multi-systemic manifestations and difficulty in identifying this rare disease, a comprehensive and meticulous diagnostic work-up is crucial.

Recommendations for Managing Adults With Histiocytic Neoplasms: New NCCN Guidelines

The histiocytoses, a group of clonal and reactive conditions, arise from monocytic macrophage or dendritic cell lineages. The current NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Histiocytic Neoplasms reflect the most up-to-date, evidence-based data relating to the evaluation and management of this disease. Specifically, the guidelines focus on adult Langerhans cell histiocytosis, Erdheim-Chester disease, and Rosai-Dorfman disease. Because these disorders are rare, challenges have arisen regarding clinical suspicion, histologic diagnosis, treatment, and molecular subtyping. Future versions of the NCCN Guidelines will address the diagnosis and management of pediatric patients, as well as malignant histiocytosis.

Survivorship Issues in Adult Patients With Histiocytic Neoplasms

Adult-onset histiocytoses (AOH), primarily Rosai-Dorfman disease (RDD), Erdheim-Chester Disease (ECD), and adult Langerhans cell histiocytosis (ALCH), are a group of related histiocytic neoplastic disorders featuring multisystemic manifestations. The disorders are largely incurable, and are essentially chronic neoplastic diseases with a variable prognosis. Prompt diagnosis and treatment is important to prevent debilitating and even life-threatening complications. Survivorship issues abound in AOH, due to their multisystemic manifestations and the sometimes recalcitrant chronic inflammation, which can lead to other debilitating complications such as fatigue, weakness, and pain. Because these disorders are rare, few healthcare professionals are proficient in their management; therefore the aim of these guidelines is to offer guidance on how to manage patients, and how to create survivorship care plans through the efforts of an interdisciplinary team.

Cervical Lymphadenopathies as Unusual Presentations of Erdheim-Chester Disease: The Need for Knowledge for Diagnosis and Treatment

The appearance of cervical adenopathies can occur in many pathologies in a non-specific manner; Erdheim–Chester disease (ECD) is characterized by xanthogranulomatous and xanthomatous infiltration of different tissues with numerous foamy histiocytes. Bone lesions are frequent and radiological features are pathognomonic for diagnosis, but lymph node involvement is exceptional and is not a form of presentation reported in the literature. Recurrent BRAFV600E mutation and others have been discovered in recent years. Since then, several treatments targeting the BRAF and MEK pathways have been developed with high success rates; even so, interferon-α continues to be one of the most widely used treatments. The best imaging test for the study and monitoring of the disease is PET-CT. The prognosis of ECD is relatively poor, with a survival of 43% of patients after 32 months follow-up. Higher survival rates have been reported in patients treated with interferon. The authors present an exceptional case of ECD with cervical adenopathies as a debut, highlighting the need for the knowledge of the disease for differential diagnosis, early treatment, and the importance of communication between the clinician and the pathologist. The main features of the disease and a brief discussion of current diagnosis and treatment are reviewed.

Histiocytic disorders

The historic term 'histiocytosis' meaning 'tissue cell' is used as a unifying concept for diseases characterized by pathogenic myeloid cells that share histological features with macrophages or dendritic cells. These cells may arise from the embryonic yolk sac, fetal liver or postnatal bone marrow. Prior classification schemes align disease designation with terminal phenotype: for example, Langerhans cell histiocytosis (LCH) shares CD207+ antigen with physiological epidermal Langerhans cells. LCH, Erdheim-Chester disease (ECD), juvenile xanthogranuloma (JXG) and Rosai-Dorfman disease (RDD) are all characterized by pathological ERK activation driven by activating somatic mutations in MAPK pathway genes. The title of this Primer (Histiocytic disorders) was chosen to differentiate the above diseases from Langerhans cell sarcoma and malignant histiocytosis, which are hyperproliferative lesions typical of cancer. By comparison LCH, ECD, RDD and JXG share some features of malignant cells including activating MAPK pathway mutations, but are not hyperproliferative. 'Inflammatory myeloproliferative neoplasm' may be a more precise nomenclature. By contrast, haemophagocytic lymphohistiocytosis is associated with macrophage activation and extreme inflammation, and represents a syndrome of immune dysregulation. These diseases affect children and adults in varying proportions depending on which of the entities is involved.

Erdheim-Chester disease with long-standing diabetes insipidus and generalized edema

Erdheim-Chester disease (ECD) is a rare non-Langerhans histiocytosis. ECD is detected more frequently due to increased awareness of healthcare providers and improved diagnostic tools. This report describes a 51-year-old woman with a history of weakness, bone pain, xanthelasma palpebrarum, and diabetes insipidus. ECD is a multisystemic condition with a poor prognosis. This disease should be considered in patients with diabetes insipidus, bone pain, and multiorgan involvements.

Histiocytosis and the nervous system: from diagnosis to targeted therapies

Histiocytoses are heterogeneous hematopoietic diseases characterized by the accumulation of CD68(+) cells with various admixed inflammatory infiltrates. The identification of the pivotal role of the mitogen-activated protein kinase (MAPK) pathway has opened new avenues of research and therapeutic approaches. We review the neurologic manifestations of 3 histiocytic disorders with frequent involvement of the brain and spine: Langerhans cell histiocytosis (LCH), Erdheim-Chester disease (ECD), and Rosai-Dorfman-Destombes disease (RDD). Central nervous system (CNS) manifestations occur in 10%-25% of LCH cases, with both tumorous or neurodegenerative forms. These subtypes differ by clinical and radiological presentation, pathogenesis, and prognosis. Tumorous or degenerative neurologic involvement occurs in 30%-40% of ECD patients and affects the hypothalamic-pituitary axis, meninges, and brain parenchyma. RDD lesions are typically tumorous with meningeal or parenchymal masses with strong contrast enhancement. Unlike LCH and ECD, neurodegenerative lesions or syndromes have not been described with RDD. Familiarity with principles of evaluation and treatment both shared among and distinct to each of these 3 diseases is critical for effective management. Refractory or disabling neurohistiocytic involvement should prompt the consideration for use of targeted kinase inhibitor therapies.

Urinary involvement in Erdheim-Chester disease: computed tomography imaging findings

PURPOSE

To describe the urological manifestations of Erdheim-Chester disease (ECD) and their computed tomography (CT) findings.

METHODS

We retrospectively reviewed 48 patients diagnosed with ECD at Peking Union Medical College Hospital from January 2014 to January 2020. Twenty-four patients exhibited urological manifestations. Their CT findings, including appearances of the involved area (e.g., perirenal space, renal sinus, ureters, renal arteries, and adrenal glands), occurrence rate of ECD involvement in each area, signal enhancement pattern after CT contrast agent administration, disease progression, and causes of hydronephrosis were discussed.

RESULTS

In 24 patients with evidence of ECD urological involvement, the most common manifestation was perirenal infiltration, appearing as "hairy kidney" on unenhanced CT scans and moderate signal enhancement on enhanced CT scans (17/24, 70.8%). Other manifestations included renal sinus infiltration (16/24, 66.7%), proximal ureter involvement (14, 58.3%), renal artery sheath (10, 41.7%), hydronephrosis (14, 58.3%), and adrenal glands involvement (8, 33.3%). The histiocytic infiltrate was mostly bilateral, starting from the perirenal space and spreading to the renal sinus and ureters. Hydronephrosis was usually associated with infiltration of ureters.

CONCLUSION

Kidneys are the most common visceral organs affected by ECD. CT scanning is not only advantageous in early diagnosis, but also critical for designing the treatment regime for patients with ECD.

Adult-Onset Xanthogranuloma With Frontal Nerve and Intracranial Involvement

Adult-onset xanthogranuloma (AOX) typically affects the preseptal and anterior orbital regions. The authors report a 49-year-old man with a 6-month history of unilateral AOX, demonstrating diffuse extraconal and intraconal orbital involvement, including the lacrimal gland and extraocular muscles. There was frontal nerve enlargement, intracranial and pterygopalatine fossa involvement. Investigations excluded IgG4 disease and Erdheim-Chester disease. This case illustrates that AOX may be added to the causes of orbital nerve enlargement and may demonstrate intracranial extension.

Pulmonary manifestations of Erdheim-Chester disease: clinical characteristics, outcomes and comparison with Langerhans cell histiocytosis

Erdheim-Chester disease (ECD) is a rare form of non-Langerhans cell histiocytosis that typically affects many organs, including the lung and pleura. However, there are few studies concerning pulmonary involvement in ECD patients, as well as the difference of pulmonary involvement between ECD and Langerhans cell histiocytosis (LCH). We performed a retrospective study of 54 ECD patients, and compared the pulmonary manifestations with those of adult LCH patients in our centre. The median age of diagnosis of the 54 ECD patients was 48 years (range 9-66 years). Chest computed tomography (CT) scans revealed lung involvement in 49 (91%) patients and pleural involvement in 34 (63%). Thirty-three (61%) patients had interstitial lung disease (ILD) with varying degrees of interlobular septal thickening, micronodules, and ground-glass opacities. ECD and LCH patients with pulmonary involvement showed significant differences in smoking status (P < 0·001), respiratory symptoms (P = 0·001) such as cough and pneumothorax (P < 0·001), and radiological findings, including cysts (P < 0·001), opacities (P < 0·001), and pleural thickening (P < 0·001). With a median follow-up duration of 24 months (range, 1-84 months), the estimated three-year overall survival (OS) of this entire ECD cohort was 90·2%. Patients with ILD tended to have worse progression-free survival (PFS) than those with no ILD (P = 0·29).

BRAF-Mutated Erdheim-Chester Disease: Profound Response to Vemurafenib Visualized With Serial Multimodality Imaging

Erdheim-Chester disease (ECD) is an extremely rare and aggressive non-Langerhans histiocytic disorder. ECD typically presents with bone pain in middle-aged adults, although some patients present with multisystem disease involving the skeleton, central nervous system, cardiovascular system, lungs, and other disease sites. The etiology of ECD is currently unknown, but it is thought to be a reactive or neoplastic disorder. Recently, mutation of the BRAF gene has been found in >50% of ECD cases, and this gene has become a therapeutic target for patients with ECD. Vemurafenib, a BRAF inhibitor, has been approved by the FDA for treatment of ECD. This report presents an elderly male patient with an aggressive phenotype of ECD and highlights the utility of multimodality imaging in monitoring the clinical course and disease response to treatment with vemurafenib.

Indolent renal involvement with BRAFV600E mutation: Erdheim-Chester, a rare disease with a wide spectrum of clinical manifestations

We present the case of a patient with three-year indolent bilateral ureteral and perirenal masses. Clinical presentation, radiological context, and histopathological findings with detection of BRAF V600E mutation confirmed the diagnosis of Erdheim-Chester disease (ECD). A review of current knowledge regarding diagnosis, clinical assessment, management, and treatment of ECD is also presented.

The combined prevalence of classified rare rheumatic diseases is almost double that of ankylosing spondylitis

BACKGROUND

Rare diseases (RDs) affect less than 5/10,000 people in Europe and fewer than 200,000 individuals in the United States. In rheumatology, RDs are heterogeneous and lack systemic classification. Clinical courses involve a variety of diverse symptoms, and patients may be misdiagnosed and not receive appropriate treatment. The objective of this study was to identify and classify some of the most important RDs in rheumatology. We also attempted to determine their combined prevalence to more precisely define this area of rheumatology and increase awareness of RDs in healthcare systems. We conducted a comprehensive literature search and analyzed each disease for the specified criteria, such as clinical symptoms, treatment regimens, prognoses, and point prevalences. If no epidemiological data were available, we estimated the prevalence as 1/1,000,000. The total point prevalence for all RDs in rheumatology was estimated as the sum of the individually determined prevalences.

RESULTS

A total of 76 syndromes and diseases were identified, including vasculitis/vasculopathy (n = 15), arthritis/arthropathy (n = 11), autoinflammatory syndromes (n = 11), myositis (n = 9), bone disorders (n = 11), connective tissue diseases (n = 8), overgrowth syndromes (n = 3), and others (n = 8). Out of the 76 diseases, 61 (80%) are classified as chronic, with a remitting-relapsing course in 27 cases (35%) upon adequate treatment. Another 34 (45%) diseases were predominantly progressive and difficult to control. Corticosteroids are a therapeutic option in 49 (64%) syndromes. Mortality is variable and could not be determined precisely. Epidemiological studies and prevalence data were available for 33 syndromes and diseases. For an additional eight diseases, only incidence data were accessible. The summed prevalence of all RDs was 28.8/10,000.

CONCLUSIONS

RDs in rheumatology are frequently chronic, progressive, and present variable symptoms. Treatment options are often restricted to corticosteroids, presumably because of the scarcity of randomized controlled trials. The estimated combined prevalence is significant and almost double that of ankylosing spondylitis (18/10,000). Thus, healthcare systems should assign RDs similar importance as any other common disease in rheumatology.

Cerebral Microvascular Erdheim-Chester Disease: A Perivascular Hematopoietic Vasculopathy

Erdheim-Chester disease (ECD) is a rare and elusive hematopoietic malignancy that may involve the nervous system in various ways. Cerebrovascular ECD involves the perivascular infiltration and compromise of any cervicocranial vessel by transformed proliferating histiocytes. Presented is the novel case of a patient with pathologically proven perivascular microangiopathy, manifesting in multifaceted fashion with ischemia, hemorrhage, mass lesions, and edema.

Rosai-Dorfman disease mimicking images of meningiomas: Two case reports and literature review

Background:

Rosai-Dorfman disease (RDD) is a rare non-Langerhans cell histiocytic proliferative disorder classically as a massive cervical lymphadenopathy. However, over the years, extranodal locations were confirmed with the central nervous system involvement in less than 5% of cases, which is marked as a significant differential diagnosis of meningiomas, with which they are widely confused due to the similarity of their radiological images.

Case Description:

We report a 37-year-old man and 45-year-old man who were diagnosed with intracranial RDD but whose radiological images mimic meningiomas, requiring anatomopathological and tumor’s immunohistochemistry for definitive diagnosis. Moreover, a review of 184 publications with 285 cases of intracranial involvement of this disease was also performed, comparing these findings with those brought in the previous studies.

Conclusion:

Intracranial Rosai-Dorfman tumors should always be remembered as differential diagnosis of meningiomas since they are similar radiologically and macroscopically. Once remembered and diagnosed, the lesion must be treated following the same pattern of resection done in meningiomas and, treatment’s differences will not occur in the surgical excision technique, but in complementary chemotherapy implementation, radiotherapy, and even with radiosurgery aid, depending on the case. Thus, it is possible to obtain better results than with just the isolated surgical procedure.

Xanthomatous Inflammatory Infiltrate Involving the Spleen: An Unusual Presentation of Erdheim-Chester Disease and Review of the Literature

Patient: Male, 63-year-old

Final Diagnosis: Erdheim-Chester disease

Symptoms: Splenic rupture

Medication: —

Clinical Procedure: Splenectomy

Specialty: Anatomy • Hematology • Pathology

Oncogene-induced maladaptive activation of trained immunity in the pathogenesis and treatment of Erdheim-Chester disease

Trained immunity (TI) is a pro-inflammatory program induced in monocyte/macrophages upon sensing of specific pathogens and characterized by immunometabolic and epigenetic changes enhancing cytokine production. Maladaptive activation of TI (i.e., in the absence of infection) might result in detrimental inflammation and disease development; however, the exact role and extent of inappropriate activation of TI in the pathogenesis of human diseases is undetermined. Here, we reveal oncogene-induced, maladaptive induction of TI in the pathogenesis of a human inflammatory myeloid neoplasm (Erdheim-Chester disease, ECD, characterized by the BRAFV600E oncogenic mutation in monocyte/macrophages and excess cytokine production). Mechanistically, myeloid cells expressing BRAFV600E exhibit all molecular features of TI: activation of the AKT/mTOR signaling axis; increased glycolysis, glutaminolysis, and cholesterol synthesis; epigenetic changes on promoters of genes encoding cytokines; and enhanced cytokine production leading to hyper-inflammatory responses. In ECD patients, effective therapeutic strategies contrast this maladaptive TI phenotype; in addition, pharmacologic inhibition of immunometabolic changes underlying TI (i.e., glycolysis) effectively dampens cytokine production by myeloid cells. This study reveals the deleterious potential of inappropriate activation of TI in the pathogenesis of human inflammatory myeloid neoplasms, and the opportunity for inhibition of TI in conditions characterized by maladaptive myeloid-driven inflammation.

Erdheim-Chester disease: a comprehensive review from the ophthalmologic perspective

Erdheim-Chester disease (ECD) is a rare clonal histiocytic neoplasm with less than 1200 documented cases to date. The disease is life-threatening and difficult to recognize, although increasing awareness as well as the integration of clinical, imaging, pathology information , and genetic studies have led to a recent exponential increase in new reported cases. ECD affects multiple organs and systems, including skeletal, neurologic, and cardiovascular. Pulmonary, retroperitoneal, and cutaneous lesions have also been reported in various combinations. Until the discovery that more than half of ECD patients harbor the BRAF-V600E mutation or other mutations in the mitogen-activated protein kinase (MAPK) and RAS pathways, Interferon-a was the first-line treatment. Nowadays BRAF and MEK-inhibitors targeted therapies are the mainstay of treatment. Ophthalmologic involvement occurs in 25% -30% of ECD cases, usually in the form of orbital involvement presenting with exophthalmos and ophthalmoplegia. Other ophthalmologic manifestations include palpebral xanthelasmas, anterior uveitis and vitritis, optic disk edema, choroidal infiltration, recurrent serous retinal detachment, retinal drusen-like deposits and retinal pigment epithelial changes. ECD patients can also present with ocular symptoms as a result of adverse effects of the treatment regimens. In some cases with smoldering or protean symptoms, the emergence of eye manifestations triggered the diagnosis. Ophthalmologists have to be aware of the disease, recognize the constellation of ECD symptoms, and contribute to the diagnosis, treatment, and follow-up of ECD patients.

High frequency of clonal hematopoiesis in Erdheim-Chester disease

Erdheim-Chester disease (ECD) is a clonal hematopoietic disorder characterized by the accumulation of foamy histiocytes within organs (in particular, frequent retroperitoneal involvement) and a high frequency of BRAFV600E mutations. Although ECD is not commonly recognized to have overt peripheral blood (PB) or bone marrow (BM) disease, we recently identified that ECD patients have a high frequency of a concomitant myeloid malignancy. We thus conducted a systematic clinical and molecular analysis of the BM from 120 ECD patients. Surprisingly, 42.5% of ECD patients (51 of 120) had clonal hematopoiesis whereas 15.8% of patients (19 of 120) developed an overt hematologic malignancy (nearly all of which were a myeloid neoplasm). The most frequently mutated genes in BM were TET2, ASXL1, DNMT3A, and NRAS. ECD patients with clonal hematopoiesis were more likely to be older (P < .0001), have retroperitoneal involvement (P = .02), and harbor a BRAFV600E mutation (P = .049) than those without clonal hematopoiesis. The presence of the TET2 mutation was associated with a BRAFV600E mutation in tissue ECD lesions (P = .0006) and TET2-mutant ECD patients were more likely to have vascular involvement than TET2 wild-type ECD patients. Clonal hematopoiesis mutations in ECD were detected in cells derived from CD34+CD38- BM progenitors and PB monocytes but less frequently present in PB B and T lymphocytes. These data identify a heretofore unrecognized high frequency of clonal hematopoiesis in ECD patients, reaffirm the development of additional high risk of myeloid neoplasms in ECD, and provide evidence of a BM-based precursor cell of origin for many patients with ECD.

MAP-Kinase-Driven Hematopoietic Neoplasms: A Decade of Progress in the Molecular Age

Mutations in members of the mitogen-activated protein kinase (MAPK) pathway are extensively studied in epithelial malignancies, with BRAF mutations being one of the most common alterations activating this pathway. However, BRAF mutations are overall quite rare in hematological malignancies. Studies over the past decade have identified high-frequency BRAF V600E, MAP2K1, and other kinase alterations in two groups of MAPK-driven hematopoietic neoplasms: hairy cell leukemia (HCL) and the systemic histiocytoses. Despite HCL and histiocytoses sharing common molecular alterations, these are phenotypically distinct malignancies that differ in respect to clinical presentation and suspected cell of origin. The purpose of this review is to highlight the molecular advancements over the last decade in the histiocytic neoplasms and HCL and discuss the impact these insights have had on our understanding of the molecular pathophysiology, cellular origins, and therapy of these enigmatic diseases as well as perspectives for future research directions.

Enfermedad de Chester Erdheim costal: reporte de caso y revisión de la literatura

Introducción. La enfermedad de Erdheim Chester es un trastorno infrecuente, de etiología no clara y edad de presentación variable, que se caracteriza por la proliferación anormal de histiocitos no Langerhans. Puede presentarse de forma asintomática, con manifestaciones locales o como complicaciones sistémicas. El diagnóstico se basa en las condiciones clínicas del paciente, estudios imagenológicos y el estudio anatomopatológico, mediante el cual se confirma la enfermedad. Caso clínico. Paciente masculino con una lesión lítica en el séptimo arco costal, inicialmente asintomático y posteriormente con dolor torácico persistente. Se realizó resección y reconstrucción de la pared torácica, con resolución de la sintomatología y adecuada evolución posoperatoria. El resultado de la patología confirmó el diagnóstico de enfermedad de Erdheim Chester. Discusión. Se presenta el caso de un paciente con compromiso costal y fractura patológica como localización y manifestación inusual de la enfermedad de Erdheim Chester, tratado quirúrgicamente de forma adecuada, y sin aparición de recidiva. Debido a la diversidad de síntomas que pueden presentar y a la afectación de múltiples órganos, además de los estudios imagenológicos, la clínica debe orientar los exámenes complementarios, como electro o ecocardiograma, resonancia nuclear magnética, o angioTAC. En los pacientes asintomáticos se ha recomendado un manejo expectante y en los sintomáticos el tratamiento médico con glucocorticoides, inhibidores de BRAF e interferón alfa. El papel de la cirugía no ha sido estudiado a profundidad.

Erdheim-Chester disease: an unusual aetiology of bilateral lipomatous perinephric masses

A 53-year-old man presented with a history of progressive abdominal distention for 1 year. Physical examination revealed large palpable masses in the bilateral flank regions. Contrast-enhanced CT of the abdomen showed bilateral, symmetrical large perinephric masses with fat attenuating areas, which was further confirmed on MRI. CT of the paranasal sinuses revealed circumscribed extraconal soft tissue mass in the left orbit, causing scalloping and erosion of the left orbital roof. Fluorine-18 fluorodeoxyglucose (FDG) positron emission tomography/CT showed FDG uptake in the bilateral perinephric masses. Based on imaging appearance, a diagnosis of Erdheim-Chester disease (ECD) was suggested. Ultrasound-guided biopsy from perinephric masses revealed a sheet of histiocytes with sprinkled lymphocytes and plasma cells in the background. The histiocytes were immunopositive for CD68, S100 and immunonegative for CD1a, which confirmed the diagnosis of ECD. The patient was started on interferon-α-2a and showed symptomatic improvement.

18F-FDG PET/CT versus anatomic imaging for evaluating disease extent and clinical trial eligibility in Erdheim-Chester disease: results from 50 patients in a registry study

OBJECTIVES

The aim of this study was to [1] characterize distribution of Erdheim-Chester Disease (ECD) by 18F-FDG PET/CT and [2] determine the utility of metabolic (18F-FDG PET/CT) imaging versus anatomic imaging (CT or MRI) in evaluating ECD patients for clinical trial eligibility.

METHODS

18F-FDG PET/CT and corresponding CT or MRI studies for ECD patients enrolled in a prospective registry study were reviewed. Sites of disease were classified as [1] detectable by 18F-FDG PET only, CT/MRI only, or both and as [2] measurable by modified PERCIST (mPERCIST) only, RECIST only, or both. Descriptive analysis was performed and paired t test for between-group comparisons.

RESULTS

Fifty patients were included (mean age 51.5 years; range 18-70 years). Three hundred thirty-three disease sites were detected among all imaging modalities, 188 (56%) by both 18F-FDG PET and CT/MRI, 67 (20%) by 18F-FDG PET only, 75 (23%) by MRI brain only, and 3 (1%) by CT only. Of 178 disease sites measurable by mPERCIST or RECIST, 40 (22%) were measurable by both criteria, 136 (76%) by mPERCIST only, and 2 (1%) by RECIST only. On the patient level, 17 (34%) had mPERCIST and RECIST measurable disease, 30 (60%) had mPERCIST measurable disease only, and 0 had RECIST measurable disease only (p < 0.0001).

CONCLUSION

Compared with anatomic imaging, 18F-FDG PET/CT augments evaluation of disease extent in ECD and increases identification of disease sites measurable by formal response criteria and therefore eligibility for clinical trials. Complementary organ-specific anatomic imaging offers the capacity to characterize sites of disease in greater anatomic detail.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03329274.

Mixed Langerhans Cell Histiocytosis and Erdheim-Chester Disease in a Girl: A Rare and Puzzling Diagnosis

OBJECTIVE

The objective of this study was to report the case of a girl diagnosed as suffering from multisystem, BRAF V600E-positive refractory Langerhans cell histiocytosis (LCH) and coexistent Erdheim-Chester disease (ECD) with perirenal, intracranial involvement and the dramatic response to clofarabine treatment.

OBSERVATIONS

Histiocytoses are rare diseases with a broad clinical spectrum. Recent evidence supports a molecular and clinical overlap between LCH and ECD, and mixed LCH/ECD is now a separate entity. However, only a few pediatric cases of mixed disease have been reported in the literature.

CONCLUSIONS

In a child with refractory, multisystem histiocytosis and atypical presentations, mixed LCH/ECD should be suspected in the differential diagnosis.

Isolated thoracic intramedullary Erdheim-Chester disease presenting with paraplegia: a case report and literature review

BACKGROUND

Erdheim-Chester disease (ECD) is a rare, idiopathic, systemic non-Langerhans cell histiocytosis involving long bone and visceral organs. Central nervous system (CNS) involvement is uncommon and most cases develop as a part of systemic disease. We present a rare case of variant ECD as an isolated intramedullary tumor.

CASE PRESENTATION

A 75-year-old female patient with a medical history of diabetes and hypertension presented with sudden-onset flaccid paraparesis for 1 day. Neurological examination revealed grade 2-3 weakness in both legs, decreased deep tendon reflex, loss of anal tone, and numbness below T4. Leg weakness deteriorated to G1 before surgery. Preoperative magnetic resonance imaging (MRI) and ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) showed an intramedullary mass lesion at T2-T4 with no systemic lesion, which was heterogeneous enhancement pattern with cord swelling and edema from C7 to T6. Gross total removal was achieved for the white-gray-colored and soft-natured intramedullary mass lesion with an ill-defined boundary. Histological finding revealed benign histiocytic proliferation with foamy histiocytes and uniform nuclei. We concluded it as an isolated intramedullary ECD. The patient showed self-standing and walkable at 18-month with no evidence of recurrence and new lesion on spine MRI and whole-body FDG-PET/CT until sudden occurrence of unknown originated thoracic cord infarction.

CONCLUSIONS

We experienced an extremely rare case of isolated intramedullary ECD, which was controlled by surgical resection with no adjuvant therapy. Histological examination is the most important for final diagnosis, and careful serial follow-up after surgical resection is required to identify the recurrence and progression to systemic disease.

Intracranial mass lesions and skin discoloration in the armpits as unusual clues to Erdheim-Chester disease: a case report

Background

Erdheim–Chester disease (ECD) is a non-Langerhans histiocytosis that results in multi-organ disease involving the skin, bones, lungs and kidneys. Central nervous system (CNS) involvement occurs in about 50 % of patients, and diabetes insipidus, visual disturbances, and cerebellar ataxia are the most frequent neurological signs. We report a case of Erdheim-Chester disease with central nervous system involvement in the form of enhancing intracranial mass lesions with massive edema.

Case presentation

The patient presented with vertigo, ataxia, encephalopathy and pyramidal signs. Diagnosis was suggested by xanthomatous skin lesions and a biopsy was compatible with Erdheim-Chester disease demonstrating xanthogranulomas CD68 positive (clone KP1) and CD1a and S100 negative. Testing for BRAF mutation was negative, which precluded treatment with Vemurafenib. Treatment with steroids and interferon resulted in improvement of neurological signs and regression of edema on MRI.

Conclusions

The diagnosis of Erdheim-Chester disease should be considered in intracranial mass lesions. Xanthomatous skin lesions are a clue to the diagnosis.

Erdheim-Chester disease: consensus recommendations for evaluation, diagnosis, and treatment in the molecular era

Erdheim-Chester disease (ECD) is a rare histiocytosis that was recently recognized as a neoplastic disorder owing to the discovery of recurrent activating MAPK (RAS-RAF-MEK-ERK) pathway mutations. Typical findings of ECD include central diabetes insipidus, restrictive pericarditis, perinephric fibrosis, and sclerotic bone lesions. The histopathologic diagnosis of ECD is often challenging due to nonspecific inflammatory and fibrotic findings on histopathologic review of tissue specimens. Additionally, the association of ECD with unusual tissue tropism and an insidious onset often results in diagnostic errors and delays. Most patients with ECD require treatment, except for a minority of patients with minimally symptomatic single-organ disease. The first ECD consensus guidelines were published in 2014 on behalf of the physicians and researchers within the Erdheim-Chester Disease Global Alliance. With the recent molecular discoveries and the approval of the first targeted therapy (vemurafenib) for BRAF-V600-mutant ECD, there is a need for updated clinical practice guidelines to optimize the diagnosis and treatment of this disease. This document presents consensus recommendations that resulted from the International Medical Symposia on ECD in 2017 and 2019. Herein, we include the guidelines for the clinical, laboratory, histologic, and radiographic evaluation of ECD patients along with treatment recommendations based on our clinical experience and review of literature in the molecular era.

Long-term follow-up of mTOR inhibition for Erdheim-Chester disease

Two articles this week focus on Erdheim-Chester disease (ECD), a rare histiocytosis that mainly affects adults. Clonal somatic mutations primarily involving proteins in the BRAF and MPAK pathways have established ECD as a myeloid neoplasm, with targeted therapies now available for patients. In the first paper, an international panel presents new consensus recommendations for evaluation and treatment of ECD. In the second paper, Pegoraro and colleagues present long-term outcomes of patients with ECD treated with sirolimus, with responses in patients both with and without BRAF mutations.

Erdheim-Chester Disease and Langerhans Cell Histiocytosis: A Case of Overlap Syndrome

Only 500 cases of Erdheim‐Chester disease have been reported in the literature to date. To increase awareness of this rare disease, this letter to the editor describes the unusual case of a woman who was diagnosed with mixed histiocytosis: Erdheim‐Chester disease and Langerhans cell histiocytosis.

Atypical cutaneous histiocytic eruption in a patient with chronic myelomonocytic leukemia: A case report

Chronic myelomonocytic leukemia (CMML) is a clonal hematopoietic stem cell malignancy with features of both a myeloproliferative neoplasm and a myelodysplastic syndrome. We present a case of 72-year-old man with CMML who presented with generalized hemorrhagic papules and plaques which on histopathology showed a peculiar infiltrate of atypical mature histiocytes. The immunohistochemical markers for Langerhans cells, indeterminate dendritic cells, and plasmacytoid dendritic cells were negative. Next generation sequencing performed on the paraffin block of the leg biopsy specimen revealed identical ASXL1, SRSF2, and KRAS mutations as seen in the CMML clone of the peripheral blood. Along with recent literature, this case illustrates the spectrum of histiocytic and dendritic cell proliferations in CMML, many of which may be clonally related to the hematopoietic malignancy.

Oral Findings of Erdheim-Chester Disease: A Case Report and Review of the Literature

Erdheim-Chester Disease (ECD) is a rare non-Langerhans cell histiocytosis characterized by histiocytic infiltration of multiple organ systems, including the bony skeleton, central nervous system, cardiovascular system, lungs, and kidneys. Manifestations of the disease are highly variable, ranging from focal disease to multisystem involvement. Oral manifestations are exceedingly rare, with only 10 known reports of ECD involving the jaws. The objective of this case report is to highlight the radiographic, clinical, and histological features of ECD involving the maxillofacial complex. A 35-year-old male admitted for sepsis secondary to pyelonephritis and suspected diabetes insipidus received an extensive workup for ECD versus IgG4 disease versus lymphoma. The oral-maxillofacial surgery service was consulted for biopsy of maxillary lesions noted to have increased activity on positron emission tomography. Intraoral biopsy yielded the characteristic histopathological features of ECD, confirming the diagnosis. We compare the clinical, radiographic, and microscopic features of ECD with past findings, contributing to the profile of this rare disease.

Bone fragility in patients affected by congenital diseases non skeletal in origin

BACKGROUND

Bone tissue represents a large systemic compartment of the human body, with an active metabolism, that controls mineral deposition and removal, and where several factors may play a role. For these reasons, several non-skeletal diseases may influence bone metabolism. It is of a crucial importance to classify these disorders in order to facilitate diagnosis and clinical management. This article reports a taxonomic classification of non-skeletal rare congenital disorders, which have an impact on bone metabolism METHODS: The International Osteoporosis Foundation (IOF) Skeletal Rare Diseases Working Group (SRD-WG), comprised of basic and clinical scientists, has decided to review the taxonomy of non-skeletal rare disorders that may alter bone physiology.

RESULTS

The taxonomy of non-skeletal rare congenital disorders which impact bone comprises a total of 6 groups of disorders that may influence the activity of bone cells or the characteristics of bone matrix.

CONCLUSIONS

This paper provides the first comprehensive taxonomy of non-skeletal rare congenital disorders with impact on bone physiology.

Cerebellar ataxia and exercise intolerance in Erdheim-Chester disease

Background

Erdheim-Chester disease (ECD), a rare disorder of monocyte/macrophage lineage, has been related to cerebellar dysfunction. To increase the awareness of this rare, protean disease, an unusual, myasthenia-like onset of ECD is reported.

Case presentation

A 42-year-old man presented with a 6-year history of mild evening fatigability in his four limbs followed by motor and cognitive symptoms associated with cerebellar atrophy, dentate nuclei and dentato-thalamic pathway degeneration. Magnetic resonance imaging revealed hyperintense signals in T2 and fluid-attenuated inversion recovery sequences within the pons, cerebellar white matter, dentate nuclei and globi pallidi in the absence of any contrast enhancement. Whole-body bone scintigraphy with ⁹⁹Technetium - methylene diphosphonate and fluorodeoxyglucose-positron emission tomography both revealed symmetric uptake in the lower extremities a finding suggestive of a diagnosis of ECD. Histological examination revealed diffuse infiltration of CD 68⁺ histiocytes with foamy cytoplasms in the presence of B-type of Rapidly Accelerated Fibrosarcoma protein kinase (BRAF)^V600E activating mutation in tumor cells.

Conclusion

In patients with myasthenia-like symptoms who test negatively for myasthenia gravis, neurodegenerative diseases, and disorders of the hypothalamus, a diagnosis of ECD should be taken into consideration.

Highlights of the Management of Adult Histiocytic Disorders: Langerhans Cell Histiocytosis, Erdheim-Chester Disease, Rosai-Dorfman Disease, and Hemophagocytic Lymphohistiocytosis

Histiocytic disorders are an exceptionally rare group of diseases with diverse manifestations and a paucity of approved treatments, thereby leading to various challenges in their diagnosis and management. With the discovery of novel molecular targets and the incorporation of targeted agents in the management of various adult histiocytic disorders, their management has become increasingly complex. In an attempt to improve the understanding of the clinical features and management of common adult histiocytic disorders (Langerhans cell histiocytosis, Erdheim-Chester disease, Rosai-Dorfman disease, and hemophagocytic lymphohistiocytosis), we created this document based on existing literature and expert opinion.

Metabolic Resolution of Lytic Lesions in Erdheim-Chester Disease on 18F-FDG PET/CT

Erdheim-Chester disease (ECD) is a rare non-Langerhans cell histiocytic disorder with variable clinical presentation most commonly involving the skeletal system. The long bones are the most common site of involvement giving a characteristic bone scintigraphy pattern of increased bilateral symmetric uptake in metadiaphyseal regions. We describe the findings of serial F-FDG PET/CT in a 16-year-old adolescent girl with ECD, emphasizing the role of F-FDG PET/CT in response assessment of ECD.

Erdheim-Chester Disease and Acute Myeloid Leukemia with Mutated NPM1 in a Patient with Clonal Hematopoiesis: A Case Report

Background

Erdheim–Chester Disease (ECD) is a clonal non-Langerhans histiocytosis, classified as a macrophage-dendritic cell neoplasm in the 2016 WHO classification. The exact cell of origin of ECD is unknown, although some limited evidence suggests that it arises from myeloid progenitors.

Case Presentation

A 43-year-old patient, diagnosed with BRAF^V600E mutated ECD, developed NPM1⁺/FLT3⁺ acute myeloid leukemia (AML) with wild-type BRAF, 15 months after the initial ECD diagnosis. The patient received intensive chemotherapy plus midostaurin, followed by midostaurin maintenance. Six months into maintenance, the patient remains in complete remission with low-level measurable residual disease, whereas ECD shows a sustained partial metabolic response. Molecular karyotype at several distinct timepoints, namely ECD diagnosis, AML diagnosis, and following treatment of AML, highlighted a molecular signature, indicative of a persistent, underlying clonal hematopoiesis.

Conclusion

This case report suggests that ECD and AML might represent an expansion of two distinct clones in a background of clonal hematopoiesis, indicating their shared origin. Moreover, molecular karyotype might serve as a strong, inexpensive tool for revealing clonal hematopoiesis in cases of negative targeted next-generation sequencing. Finally, the moderate response of ECD to midostaurin suggests that kinase inhibition might have a potential role in ECD treatment.

Erdheim-Chester Disease: Two cases from an ophthalmic perspective

Purpose

We report two patients who presented initially to ophthalmology clinics with symptoms and signs of orbital inflammation that led to a diagnosis of Erdheim-Chester Disease (ECD).

Observations

ECD is a rare form of non-Langerhans cell histiocytosis (LCH) which is characterised by multi-system organ involvement and poor prognosis with standard therapies. Both patients were positive for the BRAF V600E mutation on genetic testing and were treated with the BRAF inhibitors Vemurafenib and Dabrafenib respectively. These cases highlight the variable clinical presentation and course of ECD, the classical radiological and histopathological findings, and the high degree of clinical suspicion necessary to reach this diagnosis.

Conclusions and importance

The combination of xanthelasma and bilateral, diffuse intraconal orbital masses must suggest to the clinician the possibility of ECD; and consideration to arrange further investigation with a full body CT or FDG PET/CT scan should be given, even in the absence of wider systemic symptoms or signs. With the advent of targeted therapies such as BRAF inhibitors, it is of even more importance that a diagnosis of ECD is established in a timely manner in order to give these patients the best chance of reduced morbidity and increased survival.

Erdheim Chester disease: a subtle quiddity; the first case reported from Nepal

Erdheim-Chester disease (ECD) is a rare entity throughout the world. This is the first case reported in Nepal. ECD is a rare aggressive, non-Langerhan's histocytosis of unknown origin with classical histological features. The patient usually presents with bone pain or skeletal symptoms along with other constitutional syndrome. Although, no definitive therapy has been approved, interferon-alfa (or Pegylated Interferon-alfa) is considered as initial therapy. In this case report, we found a patient with right-sided localized chest pain for which he was evaluated with bone scan and excisional bone biopsy and its findings support the diagnosis of ECD.