Project description:BRAF mutation testing to determine eligibility for treatment with vemurafenib was performed on archival skin lesions of a 54-year-old patient diagnosed with Erdheim-Chester disease (ECD) in 1999. Sanger sequencing of DNA extracted from a 2008 skin lesion identified two non-contiguous base substitutions in BRAF, which were shown by next-generation sequencing (NGS) to be located in the same allele. Due to its long-standing duration, molecular evolution of disease was possible; however, both Sanger and NGS of a 2000 skin lesion were unsuccessful due to the poor quality of DNA. Finally, droplet digital PCR using a probe specific for this novel mutation detected the complex BRAF mutation in both the 2000 and 2008 lesions, indicating this case to be ECD with a novel underlying BRAF p.Thr599_Val600delinsArgGlu mutation. Although well at present, molecular modelling of the mutant BRAF suggests suboptimal binding of vemurafenib and hence reduced therapeutic effectiveness.
Project description:BackgroundErdheim-Chester disease (ECD), a rare inflammatory myeloid neoplasm, is known to be fundamentally reliant on the constitutive activation of the MAPK signaling pathway in the majority of patients. Consequently, inhibition of the V600E-mutant BRAF kinase has proven to be a safe and efficacious long-term therapeutic strategy for BRAF-mutant ECD patients. Nevertheless, in a subset of patients with CNS disease, the efficacy of long-term treatment may diminish, facilitating suboptimal responses or disease progression.MethodsWe retrospectively describe 3 BRAF-mutant ECD patients whose treatment with Vemurafenib was upgraded to Vemurafenib/Cobimetinib due to either disease progression, insufficient response, or unacceptable toxicity. CNS response to therapy was evaluated using magnetic resonance imaging (MRI) and extra-cranial disease was monitored using 18F-fludeoxyglucose positron emission tomography/computed tomography (PET/CT).ResultsThree patients with a mean age of 52.6 years were treated with Vemurafenib for a mean duration of 26.6 months (range: 6-52). Monotherapies were upgraded to Vemurafenib/Cobimetinib dual therapy. The combination therapy was administered for a mean duration of 21 months (range: 19-23). All patients exhibited clinical and neurological improvement. Regression of lesions on MRI was noted in 2 patients. Both patients characterized by a PET-avid disease responded to the biological treatment regimen with complete metabolic remissions.ConclusionDual inhibition of BRAF and downstream MEK may be a safe and effective therapeutic strategy for BRAF-mutant ECD patients for whom BRAF inhibitor therapy proved insufficient and as such appropriate for the long-term management of CNS disease in ECD.
Project description:BackgroundErdheim-Chester disease (ECD) is a rare histiocytic neoplasm characterized by recurrent alterations in the MAPK (mitogen-activating protein kinase) pathway. The existing literature about the neuro-oncological spectrum of ECD is limited.MethodsWe present retrospective clinical, radiographic, pathologic, molecular, and treatment data from 30 patients with ECD neurohistiocytic involvement treated at a tertiary center.ResultsMedian age was 52 years (range, 7-77), and 20 (67%) patients were male. Presenting symptoms included ataxia in 19 patients (63%), dysarthria in 14 (47%), diabetes insipidus in 12 (40%), cognitive impairment in 10 (33%), and bulbar affect in 9 (30%). Neurosurgical biopsy specimens in 8 patients demonstrated varied morphologic findings often uncharacteristic of typical ECD lesions. Molecular analysis revealed mutations in BRAF (18 patients), MAP2K1 (5), RAS isoforms (2), and 2 fusions involving BRAF and ALK. Conventional therapies (corticosteroids, immunosuppressants, interferon-alpha [IFN-α], cytotoxic chemotherapy) led to partial radiographic response in 8/40 patients (20%) by MRI with no complete responses, partial metabolic response in 4/16 (25%), and complete metabolic response in 1/16 (6%) by 18F-fluorodeoxyglucose (FDG)-PET scan. In comparison, targeted (kinase inhibitor) therapies yielded partial radiographic response in 10/27 (37%) and complete radiographic response in 14/27 (52%) by MRI, and partial metabolic response in 6/25 (24%) and complete metabolic response in 17/25 (68%) by FDG-PET scan.ConclusionsThese data highlight underrecognized symptomatology, heterogeneous neuropathology, and robust responses to targeted therapies across the mutational spectrum in ECD patients with neurological involvement, particularly when conventional therapies have failed.
Project description:Erdheim-Chester Disease (ECD) is an extremely rare non-Langerhans histiocytosis that most often presents in the fifth to seventh decades of life. In this case report, we present a 34-year-old woman who underwent successful pericardiectomy for constrictive pericarditis secondary to ECD, which is the youngest reported patient with ECD to undergo pericardiectomy. (Level of Difficulty: Advanced.).
Project description:OBJECTIVE:To characterize the spectrum of neurologic involvement in Erdheim-Chester Disease (ECD), a treatable inflammatory neoplasm of histiocytes. METHODS:Sixty-two patients with ECD were prospectively enrolled in a natural history study that facilitated collection of clinical, imaging, laboratory, neurophysiologic, and pathologic data. RESULTS:Ninety-four percent of the patients had neurologic abnormalities on examination or imaging, and 22% had neurologic symptoms as the initial presentation of ECD. The most common neurologic findings were cognitive impairment, peripheral neuropathy, pyramidal tract signs, cranial nerve involvement, and cerebellar ataxia. Imaging revealed atrophy and demyelination along with focal lesions that were located throughout the nervous system, dura, and extra-axial structures. The BRAF V600E variant correlated with cerebral atrophy. Brain pathology revealed lipid-laden, phagocytic macrophages (histiocytes) accompanied by demyelination and axonal degeneration. INTERPRETATION:In patients with ECD, neurologic morbidity is common and contributes significantly to disability. Since neurologic symptoms can be the presenting feature of ECD and, given the mean delay in ECD diagnosis is 4.2 years, it is critical that neurologists consider of ECD and other histiocytosis in patients with inflammatory, infectious, or neoplastic-appearing white matter. Furthermore, given the broad spectrum of neurologic involvement, neurologists have an important role in a team of specialists treating ECD patients.
Project description:BackgroundErdheim-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 summaryA 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.DiscussionErdheim-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.
Project description:Treatment of Erdheim-Chester disease (ECD), a rare non-Langerhans histiocytosis, relies on interferon-?, chemotherapeutic agents such as purine analogs, cytokine-blocking agents and BRAF inhibitors. Since interleukin (IL)-6 levels are elevated in serum and lesions of ECD patients, we evaluated the therapeutic efficacy and safety of IL-6 blockade with tocilizumab. We conducted an open-label, single-arm, phase II, prospective study of tocilizumab in three patients with multisystem ECD and poor tolerance/contraindications to IFN-?. Modifications of symptoms attributed to ECD represented the criteria for evaluation of clinical response. Changes at positron emission tomography scan, computed tomography scan, and magnetic resonance imaging at month 6 represented the main criteria for the evaluation of radiological response. Sustained complete clinical response and partial radiological improvement were observed in two patients, paralleled by modulation of systemic pro-inflammatory mediators. In spite of disease stabilization or improvement at extra-neurological sites, a third patient experienced a radiologic and clinical progression of central nervous system involvement, mirrored by a dramatic increase of circulating IL-6 and related cytokines. These findings indicate that IL-6 inhibition can be effective in ECD, but caution is advisable in patients with neurologic involvement. IL-6 emerges as a central mediator in ECD pathogenesis.
Project description: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.