Erdheim-Chester Research Articles

An effective treatment in Erdheim Chester disease: vemurafenib: a case report

BackgroundErdheim Chester disease (ECD) is a rare disease with multisystemic involvement in the group of non-langerhans cell histiocytosis. Although nearly 100 years have passed since its definition, the number of cases reported all over the world is below 1000. In addition to the rarity of the disease, low awareness seems to play a role in this.Case presentation47-year-old white caucasian women patient who presented to our clinic with symptoms of weakness-fatigue as well as increasing pain in the knees and ptosis in the left eye. Result of the patient's bone biopsy, ECD was considered pathologically and BRAF V600E mutation was shown molecularly. After presenting the clinical, laboratory and other examination results of the case, the dramatic response seen with targeted therapy will be discussed.ConclusionsBRAF V600E mutation is frequently seen in ECD. Vemurafenib plays an active role in targeted therapy.

SAT614 Clinical, Laboratory And Imaging Features Associated With Central Diabetes Insipidus (Arginine Vasopressin Deficiency) In Erdheim-Chester Disease (ECD)

Abstract Disclosure: S. Vaid: None. J. Estrada-Veras: None. W. Gahl: None. P. Nicholas: None. R. Dave: None. B. Gochuico: None. K. O'Brien: None. F. Hannah-Shmouni: None. S. Shekhar: None. Background: Erdheim-Chester disease (ECD) is a rare, non-Langerhans, histiocytic multisystemic disorder commonly associated with somatic pathogenic variants in the BRAF or MAPK pathways. In ECD, diabetes insipidus (DI) is among the most common endocrinopathies and is often the presenting feature. We analyzed the prevalence and the genetic, biochemical, and imaging features associated with DI in subjects with ECD. Methods: A cross-sectional descriptive study of subjects with biopsy-confirmed ECD was conducted from January 2011 to December 2018 at the National Institutes of Health Clinical Center. Subjects underwent molecular genetics, baseline biochemical and pituitary endocrine function studies, and dedicated pituitary MRI. DI was diagnosed based on clinical and biochemical features. Other endocrinopathies were diagnosed based on standardized criteria. Continuous data were analyzed using t-tests or nonparametric tests between subjects with and without DI. Categorical data were analyzed via Fisher's exact tests. Results: Sixty-one subjects with ECD [23 females (37.7%) and 38 males (62.3%)] were evaluated. Twenty-three subjects (38%) had DI, with a higher percentage of males (87%) vs females (13%). DI subjects compared to those without DI were younger [mean (SD):50.1(10.4) vs 57.5 (14.5) years; p=0.01] and had a higher prevalence of BRAF V600E pathogenic variants [76.19% vs 39.47%; p<0.01], lower IGF-1 [mean (SEM):136.5 (13.87) vs 161.67(10.22) ng/mL; p=0.02], and lower urine osmolality [466.6 (±260.18) vs 641.05 (±179.7) mOsm/kg; p<0.01]. DI subjects also had a higher prevalence of central hypogonadism [78% vs 34%; p<0.01], a higher prevalence of panhypopituitarism [39% vs 0%; p <0.01] and a higher number of anterior pituitary deficits [mean (SEM):1.23 (1.15) vs 0.56 (0.67); p =0.01] than non-DI subjects. Subjects with DI had a higher frequency of absent posterior pituitary bright spots [61% vs 21%; p<0.01] compared to those without DI. There were no differences in BMI, serum prolactin, vasopressin, serum osmolality, serum sodium, total cholesterol or hsCRP. The frequencies of central adrenal insufficiency, central hypothyroidism and abnormal pituitary imaging were similar between the two groups. Conclusion: DI is among the most common endocrinopathies in Erdheim-Chester disease. In DI subjects, a higher burden of anterior pituitary endocrinopathies, BRAF V600E pathogenic variants and absence of the posterior pituitary bright spot was noted, which may allow for early stratification and targeted clinical management. Presentation: Saturday, June 17, 2023

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

ObjectiveTo 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 methodsThe 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. ResultsOut 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). Conclusion2-[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.

Cerebrospinal Fluid Metabolomic Pattern of Different Pituitary Stalk Lesions.

To describe the cerebrospinal fluid (CSF) metabolomic pattern of pituitary stalk lesions. CSF was collected from patients with different pituitary stalk lesions treated at Peking Union Medical College Hospital: germ cell tumor (GCT, n = 27); hypophysitis (n = 10); and Langerhans cell histiocytosis (LCH) or Erdheim-Chester disease (ECD) (LCH + ECD, n = 10). The CSF metabolome profiles were characterized by liquid chromatography-mass spectrometry (LC-MS). There were 44 metabolites that significantly differed between patients with GCT and those with hypophysitis (P < .05). Between patients with GCT with CSF level of beta subunit of human chorionic gonadotrophin (β-hCG) < 5 mIU/mL and those with hypophysitis, there were 15 differential metabolites (P < .05, fold change > 1.5 or < 1/1.5). All of the metabolites had an area under the curve (AUC) above 0.7. There were 9 metabolites that significantly differed between patients with GCT and those with LCH + ECD (P < .05) and 7 metabolites had significant differences between GCT (CSF β-hCG < 5 mIU/mL) and LCH + ECD (P < .05, fold change > 1.5 or < 1/1.5). We found 6 metabolites that were significantly different between patients with hypophysitis and those with LCH + ECD (P < .05) and 5 of these had fold change more than 1.5 or less than 1/1.5. Three metabolites, 5-deoxydiplosporin, cloversaponin I, and phytosphingosine, showed excellent capabilities to differentiate the 3 disease categories. Furthermore, we identified 67 metabolites associated with clinical test results (ρ > 0.2, P < .05) and 29 metabolites showed strong correlation (ρ > 0.4, P < .05). Our study is the first to systematically investigate the metabolomics of CSF in different pituitary stalk lesions. CSF metabolomics is a useful strategy for biomarker discovery.

Impact of BRAFV600E mutation on aggressiveness and outcomes in adult clonal histiocytosis.

Histiocytoses encompass a wide spectrum of diseases, all characterized by tissue infiltration by CD68+ histiocytes. Most adult histiocytoses are considered clonal diseases because they highlight recurrent somatic mutations in the MAP-kinase pathway gene, primarily BRAF. The presence of BRAF mutation is associated with widespread disease in children with Langerhans cell histiocytosis (LCH) or cardiovascular/neurological involvement in Erdheim-Chester disease (ECD). Nevertheless, few data are available on adult clonal histiocytosis. This is why we have conducted a retrospective study of all patients with clonal histiocytosis in our institution and present the data according to the presence of BRAF mutation. Among 27 adult patients (10 ECD, 10 LCH, 5 Rosai-Dorfman disease (RDD), and 3 mixed ECD/LCH), 11 (39%) have BRAF mutation with gain of function (n = 9) and deletion (n = 2). Those patients had frequent multicentric disease with risk organ involvement, especially the brain and cardiovascular system. They had frequent associated myeloid neoplasms (mostly chronic myelomonocytic leukemia) and received more frequently targeted therapy as the front-line therapy. Nevertheless, its presence did not affect the overall survival or relapse-free survival probably due to the emergence of efficient therapies. To conclude, rapid and accurate molecular establishment in adult clonal histiocytoses is crucial because BRAFV600E mutation correlates with multicentric disease with organ involvement and incomplete metabolic response.

Vertebral involvement of Erdheim-Chester disease: an unusual mimic of vertebral metastasis.

Vertebral involvement of Erdheim-Chester disease: an unusual mimic of vertebral metastasis.

Cardiac involvement resolution is frequent and associated with improved outcome in Erdheim-Chester disease

Cardiac involvement resolution is frequent and associated with improved outcome in Erdheim-Chester disease

Erdheim-Chester disease; a 31-year-old woman presented with bone pain and ophthalmologic involvement: a case report

Erdheim-Chester disease (ECD) is a rare non-Langerhans histiocytic disorder with no actual known incidence rate. It primarily affects multiple organs via increased expression of proinflammatory cytokines, eventually leading to histiocyte activation and infiltration at multiple sites. A 31-year-old virgin female presented with progressive generalized bone pain and blurred vision. She underwent a comprehensive clinical and paraclinical evaluation. Based on the final results, the diagnosis of ECD was established. We started treatment mainly using Interferon-α and corticosteroids, estrogen, levothyroxine, and desmopressin acetate. In adults with a mysterious chronic disease affecting multiple organs, we should always consider ECD as a differential diagnosis. Although ECD is still rare, the detection rate of this disease has increased significantly in recent decades. A comprehensive clinical and paraclinical evaluation is necessary to make a definitive diagnosis and determine the extent of the disease.

Dyadic communication in rare cancer: a registry-based study of patients with Erdheim-Chester disease and their caregivers

Dyadic communication in rare cancer: a registry-based study of patients with Erdheim-Chester disease and their caregivers

Childhood-onset Erdheim-Chester disease in the molecular era: clinical phenotypes and long-term outcomes of 21 patients

Erdheim-Chester Disease (ECD) is exceptionally rare in childhood. Among 21 children with ECD, disease phenotype and mutational profile were similar to those observed in adults, although the frequency of some clinical manifestations differed. Targeted therapies were also effective in children.

Erdheim-Chester disease with bilateral orbital masses and multi-systemic symptoms: two case reports

BackgroundErdheim–Chester disease (ECD) is a rare histiocytic disorder characterized by multisystem xanthogranulomatous infiltration by lipid-laden histiocytes. We report two cases of ECD involving the orbit and describe their clinicopathologic factors, treatments, and prognosis. One was a rare case of ECD complicated with primary thrombocytosis.Case presentationThis study describes two patients with bilateral orbital ECD. Both presented with proptosis and visual loss; imaging findings showed bilateral intraorbital masses. Both had different degrees of systemic symptoms (pleural effusion, pericardial effusion, ascites, and heart failure) before the ocular symptoms and did not find the cause before ophthalmic tumor resection and pathological biopsy. The diagnosis of ECD was confirmed after pathological biopsy and detection of BRAFV600E mutation. Patient 2 also with primary thrombocytosis and had a CALR mutation as well as the BRAFV600E mutation. Both patients were recommended to receive targeted therapy. Patient 1 refused targeted therapy for financial reasons and was discharged after local radiotherapy only. The patient had no light perception in either eye and no improvement in systemic symptoms. Patient 2 began targeted treatment after diagnosis and reached the discharge criteria 2 weeks later. He is in good condition at present, but unfortunately, his eyesight has not improved because of the irreversible damage to his visual function.ConclusionECD is easily misdiagnosed and missed because of its rarity and diverse clinical manifestations. Orbital involvement is common in ECD, and surgery is the most frequently employed approach. Despite the surgical resection is not curative, its significance lies in biopsy to establish diagnosis and/or surgical debulking to relieve mass effect, minimizing further impairment of visual function. Targeted therapy is the most effective treatment for patients with a positive BRAF mutation gene. Evaluation of a concomitant myeloid neoplasm is also critical before initiating targeted therapies for refractory ECD.

Paging all ENT specialists: Sinus manifestations of Erdheim-Chester disease.

Paging all ENT specialists: Sinus manifestations of Erdheim-Chester disease.

Histiocytes from the body to the heart: a complex case of cardiac and multi-organ involvement of Erdheim-Chester disease.

Histiocytes from the body to the heart: a complex case of cardiac and multi-organ involvement of Erdheim-Chester disease.

Performance of 68Ga-Labeled Fibroblast Activation Protein Inhibitor PET/CT in Evaluation of Erdheim-Chester Disease: A Comparison with 18F-FDG PET/CT.

Erdheim-Chester disease (ECD) involves multiple organs and tissues and has diverse manifestations, which makes it difficult to distinguish lesions caused by ECD from those caused by other diseases. Variable degrees of fibrosis are present in ECD. Therefore, we conducted a prospective cohort study to explore the ability of 68Ga fibroblast activation protein inhibitor (68Ga-FAPI) PET/CT to detect lesions in ECD patients. Methods: Fourteen patients diagnosed with ECD, as confirmed by histology, were included in this study. For every patient, 68Ga-FAPI PET/CT and 18F-FDG PET/CT were conducted within 1 wk. The positive rate and SUVmax of the lesions in the involved organs were compared between the examinations. Results: The most commonly involved organs were bone (100%), heart (57.1%), lung (57.1%), kidney (42.9%), and peritoneum or omentum (35.7%); other common manifestations were intracranial infiltration (50%) and cutaneous infiltration (35.7%). 68Ga-FAPI PET/CT detected 64 of 67 lesions in 14 patients, whereas 18F-FDG PET/CT detected 51 of 67 lesions (P = 0.004). The SUVmax for 68Ga-FAPI PET/CT was significantly higher than the SUVmax for 18F-FDG PET/CT of the heart (4.9 ± 2.4 vs. 2.8 ± 1.2, respectively; P = 0.050), lung or pleura (6.8 ± 4.9 vs. 3.1 ± 1.3, respectively; P = 0.025), peritoneum or omentum (5.7 ± 3.6 vs. 2.8 ± 1.7, respectively; P = 0.032), and kidney or perinephric infiltration (4.9 ± 1.2 vs. 2.9 ± 1.1, respectively; P = 0.009). Conclusion: The detectivity of 68Ga-FAPI PET/CT is superior to that of 18F-FDG PET/CT. Moreover, 68Ga-FAPI PET/CT has a better image contrast and higher SUVmax for lesions in multiple organs including the heart, lungs, peritoneum, and kidneys. 68Ga-FAPI PET/CT is a promising tool to assess pathologic features and disease extent in ECD patients.

Malignant Histiocytosis Comprises a Phenotypic Spectrum That Parallels the Lineage Differentiation of Monocytes, Macrophages, Dendritic Cells, and Langerhans Cells

Malignant histiocytoses (MHs), or the ‘M group’ of the Histiocyte Society classification, are characterized by neoplastic histiocytes with large pleomorphic nuclei. MH encompasses the diagnoses of histiocytic sarcoma, interdigitating dendritic cell sarcoma, and Langerhans cell sarcoma. We aimed to define the phenotypic spectrum of MH and examine the genotypic features across this spectrum. Using immunohistochemistry, we arranged the 22 cases into 4 subtypes that correspond to the lines of differentiation from monocytic and dendritic cell precursors as follows: (1) macrophage (n = 5): CD68+, CD163+, CD14+, and Factor 13a+; (2) monocyte-macrophage (n = 5): CD68+, CD163+, CD14+, S100+, and OCT2+; (3) dendritic cell (n = 6): CD68+, CD11c+, S100+, lysozyme+, ZBTB46+, and CD1a/langerin < 5%; and (4) Langerhans cell (n = 6): CD68+, CD11c+, S100+, ZBTB46+, CD1a+, and langerin+. The phenotypic subtypes align with those seen in low-grade histiocytic neoplasms as follows: MH-macrophage type correlates with Erdheim-Chester disease phenotype; MH-monocyte-macrophage type with Rosai-Dorfman disease phenotype, and MH-Langerhans cell type with Langerhans cell histiocytosis. Activating mutations in MAPK-pathway genes were identified in 80% of MH cases; 29% had mutations in the PI3k-AKT-mTOR pathway and 59% had mutations in epigenetic modulating genes. Strong expression of cyclin D1 was present in all cases, whereas p-ERK and p-AKT were not uniformly expressed. Eight of 22 (36%) MH cases were proven to be clonally related to a prior B-cell lymphoma. Defining the phenotypic spectrum of MH provides a guide to diagnosis and allows further exploration into the potential biological and clinical significance.

Sinonasal and ear manifestations of Erdheim-Chester disease.

To calculate the prevalence of sinonasal and ear involvement in an Erdheim-Chester disease (ECD) population, to describe the different ear, nose and throat (ENT) manifestations and to study the association between ENT involvement, other organ involvement, and BRAF mutations. We led a retrospective monocentric study in the national referral center for ECD. One hundred and sixty-two patients with ECD and ENT data were included between January 1, 1980 and December 31, 2020. Ear and nose clinical and radiological findings were noted. We described and studied the prevalence of ENT involvement in ECD population. The association between sinonasal and ear involvement, other organ involvement, and BRAF mutations was calculated. The prevalence of ENT manifestations is around 45%. No clinical rhinologic or otologic signs were specific to ECD. Sinus imaging was abnormal in 70% of cases. A bilateral maxillary sinus frame osteosclerosis was highly specific of ECD. Associations were found between the sinus MRI imaging type and BRAF status, central nervous system involvement, cerebellum involvement and xanthelasma. Sinonasal or ear involvement is frequent in ECD and has specific imaging features for sinuses. Trial registration: #2011-A00447-34.

CPC10 An unusual case of bilateral periorbital lesions

Abstract A 45-year-old man was referred to the dermatology department for a 5–10-year history of enlarging periorbital xanthelasma-like lesions with a non-significant lipid profile. The periorbital lesions episodically and spontaneously became swollen and were associated with a throbbing sensation. After exercise and minimal motion, haemorrhage into the lesions occurred. Clinical examination revealed multiple coalescing, symmetrical, thick, yellow plaques and nodules with red–brown areas of discoloration associated with eyelid telangiectasia. His past medical history included hiatus hernia, lipoma and Osgood-Schlatter disease of the knee. The differential diagnosis included adult-onset xanthelasma, necrobiotic xanthogranuloma and amyloidosis. Punch biopsy of the lesions showed histological features consistent with a xanthogranuloma. Owing to the association of this entity with underlying haematological malignancy, computed tomography was performed, which revealed a subtle 33 × 70 mm low-attenuating mass within the posterolateral aspect of the right iliacus muscle. On further radiological investigation, including magnetic resonance imaging (MRI) and positron emission tomography, an avid, nonaggressive right iliac bone lesion and nonavid bilateral, symmetrical metaphyseal and diaphyseal sclerosis involving both distal femur and proximal tibia were seen. Previous MRI of his knee, performed 3 years earlier following a fall, was reviewed and found to show an incidental signal abnormality in his distal femur. Tissue from the periocular xanthogranuloma was positive for the BRAF V600E mutation and tissue from biopsy of the right iliac crest was consistent with focal osteosclerosis. Owing to the histopathological, clinical and radiological features, a diagnosis of Erdheim–Chester disease (ECD) was established. As a result, the haematology team initiated the patient on a reducing dose of oral prednisolone with long-term methotrexate (15 mg weekly). This led to an improvement in appearance of the periorbital lesions. The differential diagnosis for periocular xanthogranuloma includes adult-onset xanthogranulomas and adult-onset asthma with periocular xanthogranuloma, necrobiotic xanthogranuloma and ECD. ECD is a rare form of non-Langerhans cell histiocytosis that is highly associated with BRAF V600E and other mitogen-activated protein kinase pathway mutations (Diamond EL, Durham BH, Haroche J et al. Diverse and targetable kinase alterations drive histiocytic neoplasms. Cancer Discov 2016; 6:154–65). The clinical course of ECD is generally aggressive, but it can vary from indolent disease to fatal multiorgan failure. Although ECD can have multiorgan involvement, approximately 25% of these patients have cutaneous manifestations (Kobic A, Shah KK, Schmitt AR et al. Erdheim-Chester disease: expanding the spectrum of cutaneous manifestations. Br J Dermatol 2020; 182:405–9). This case highlights the importance of considering ECD when faced with atypical periorbital lesions as these lesions can mimic common benign xanthelasma.

A phase 2 study of HLX208, a BRAFV600E inhibitor, in adult patients with Langerhans cell histiocytosis and/or Erdheim-Chester disease harboring BRAFV600E mutation.

7574 Background: HLX208 is a novel BRAFV600E inhibitor, exhibiting excellent antitumor efficacy in preclinical studies. This phase 2 study aimed to evaluate the efficacy, safety, and pharmacokinetics of HLX208 in adult patients with Langerhans cell histiocytosis (LCH) and/or Erdheim-Chester disease (ECD) harboring BRAFV600E mutation. Methods: This was a single-arm, open-label, multicenter, phase 2 study. Patients with histologically confirmed LCH and/or ECD were enrolled and received oral administration of HLX208 at 450 mg twice every day. HLX208 was given in 28-day cycles until disease progression, experiencing intolerable toxicity, withdrawal of consent, initiation of new antitumor therapy, or death, whichever occurred first. The primary endpoint was the objective response rate (ORR) assessed by independent review committee (IRC) per PET Response Criteria in Solid Tumors (PERCIST) 1.0. Secondary endpoints included safety, other efficacy measures, and pharmacokinetics of HLX208. Results: As of January 15, 2023, 22 patients with LCH and/or ECD were enrolled. All patients have received at least one dose of HLX208 and were included in the current analysis. The median age was 39 (range 18–69) years. Nine (40.9%) patients were male. 12 (54.5%) patients were diagnosed with LCH, 9 (40.9%) were diagnosed with ECD, and 1 (4.5%) had combined LCH and ECD. 6 (27.3%) patients had single system multifocal disease, while 16 (72.7%) had multisystem disease. The median follow-up duration was 4.8 months (95% CI 2.7–5.7). Among the 10 efficacy evaluable patients, ORR (unconfirmed) assessed by IRC per PERCIST 1.0 was 90.0% (95% CI 55.5–99.7%) (9/10, including 2 complete metabolic response [CMR] and 7 partial metabolic response [PMR]), while that by investigators per PERCIST 1.0 was 100.0% (95% CI 69.2–100.0%) (10/10, including 3 CMR and 7 PMR). Disease control rate was 100.0% (95% CI 69.2–100.0%) as assessed by both IRC and investigators per PERCIST 1.0. The median duration of response, median progression-free survival, and median overall survival were not reached. Of the 22 patients who received the drug, 17 (77.3%) patients experienced treatment-emergent adverse events (TEAEs); 12 (54.5%) reported treatment-related adverse events (TRAEs), most commonly alanine aminotransferase increased (36.4%), aspartate aminotransferase increased (22.7%), γ-glutamyltransferase increased (18.2%), and blood lactate dehydrogenase increased (18.2%). Most TRAEs were grade 1 (27.3%) and 2 (18.2%). Only 2 (9.1%) patients experienced grade ≥3 TRAEs and 1 (4.5%) experienced treatment-related serious adverse event. There were no TEAEs that led to treatment discontinuation or death. Conclusions: In summary, HLX208 was safe and well tolerated, and showed promising efficacy in patients with LCH and/or ECD. Clinical trial information: NCT05092815 .

Longitudinal assessment of cardiac involvement in Erdheim-Chester disease using cardiac magnetic resonance imaging.

7067 Background: Erdheim-Chester disease (ECD) is a rare multi-systemic non-Langerhans cell histiocytosis that affects the heart in nearly half of patients. Atrial infiltration and pericardial effusion are the hallmarks of cardiac involvement and can lead to clinical complications (conduction disorders, coronary artery stenosis, tamponade, constrictive pericarditis). Evolution under treatment is poorly studied. We aimed to investigate the evolution of cardiac involvement in ECD using cardiac magnetic resonance (CMR) imaging. Methods: All ECD patients with a CMR imaging disclosing a cardiac involvement and who underwent at least one follow-up CMR imaging between 2005 and 2020 at a French tertiary center were retrospectively included. First and last CMR imaging were compared. Multivariable analysis was performed to search for independent predictors of cardiac involvement resolution. Variables were included in the model if their P-value was &lt; 0.1 on univariable analysis. Results: Overall, 46 patients were included. Median age at first imaging was 63 years [53-69]. Median delay between the first and the last imaging was 4 years [2-7]. BRAFV600E mutation was present in 43 patients (94%). Patients received a median of 2 [1-3] treatments. All patients (100%) had cardiac involvement at baseline. Right atrio-ventricular sulcus (RAVS) was infiltrated in 38 patients (83%) and was the main cardiac feature.Overall, complete regression was observed in 6 patients (13%), partial regression in 26 patients (56%), stable imaging in 12 patients (26%), and worsening in 2 patients (5%). In patients with RAVS infiltration, complete regression was observed in 5 patients (16%) and partial regression was seen 22 patients (58%) regression. On univariable analysis, patients with regression of their infiltration had a lower rate of death (16% versus 64%, P= 0.002), a higher rate of atrial infiltration late gadolinium enhancement (LGE) (97% versus 71%, P= 0.01), a higher rate of hydronephrosis (50% versus 14%, P= 0.03) and a lower rate of interferon prescription (69% versus 100%, P= 0.02). A similar rate of vemurafenib use was observed in both groups (69% versus 54%, P= 0.3). On multivariable analysis, death remained significantly associated with follow-up imaging status (ß = -2.3 P= 0.01), while atrial infiltration LGE (ß = 2.7, P= 0.06), hydronephrosis (ß = 1.6, P= 0.1) and treatment with interferon (ß = -16, P= 1) were no longer significantly associated with imaging status. Conclusions: Partial or complete resolution of cardiac involvement was observed in 69% of patients with ECD and was significantly associated with a lower rate of death on multivariable analysis.

Histiocytic Lesion Masquerading as Interstitial Lung Disease—A Case Report

Erdheim Chester Disease (ECD) is a rare histiocytic neoplasm with heterogeneous features. It can frequently be misdiagnosed if proper clinical and radiological details are not available. Biopsy with confirmatory immunohistochemistry (IHC) for BRAFV600E or molecular analysis for the gene forms the mainstay of diagnosis. Most ECD patients require treatment and the choice of therapy must be individualized based on clinical characteristics. Herein is reported one such case of ECD in a 45-year-old male who remains disease-free after six months of follow-up.