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.

Pulmonary Erdheim-Chester Disease With BRAF-AGAP3 Fusion: Late-Onset Osteolytic Femoral Lesions Despite Long-Term Pulmonary Stabilization With Corticosteroid

Erdheim-Chester disease (ECD) is a rare inflammatory myeloid neoplasm affecting multiple systems and organs. The patient is a 38-year-old male with ECD complicated with pulmonary and cutaneous manifestations but without bone lesions diagnosed in 2008. Initial treatment with oral and inhaled corticosteroids achieved persistent favorable disease remission. However, atypical late-onset bone lesions developed in the bilateral femur in 2021. Although BRAF-V600E mutation was negative in the lung specimen at diagnosis, the next-generation gene sequence using biopsied bone lesions revealed a rare BRAF-AGAP3 fusion, leading to the administration of trametinib. This is the first report describing ECD harboring BRAF-AGAP3 fusion successfully treated with trametinib. Our case presents a unique clinical course in which late-onset osteolytic bone lesions developed despite a long-term stabilization of pulmonary lesions with low-dose oral and inhaled corticosteroids.

Genome-Wide Association Study Identifies the First Germline Genetic Variant Associated With Erdheim-Chester Disease

OBJECTIVE

Erdheim-Chester disease (ECD) is rare histiocytosis with a wide range of clinical manifestations. Somatic mutations are key to the pathogenesis of the disease; however, the relationship between germline genetic variants and ECD has not been examined so far. The present study aims to explore the inherited genetic component of ECD by performing the first genome-wide association study.

METHODS

After quality controls, a cohort of 255 patients with ECD and 7,471 healthy donors was included in this study. Afterward, a logistic regression followed by in silico functional annotation was performed.

RESULTS

A signal at the 18q12.3 genomic region was identified as a new susceptibility locus for ECD (P = 2.75 × 10-11 ; Odds Ratio = 2.09). This association was annotated to the SETBP1 gene, which is involved in clonal haematopoiesis. Functional annotation of this region and of the identified suggestive signals revealed additional genes that could be potentially involved in the pathogenesis of the disease.

CONCLUSION

Overall, this work demonstrates that germline genetic variants can impact on the development of ECD and suggests new pathways with a potential pathogenic role.

Double Subclavian Steal Syndrome As Initial Manifestation of Erdheim-Chester Disease: A Case Report

Erdheim-Chester disease (ECD) is a histiocytosis that infiltrates all organs, but especially large arteries such as the aorta and its branches, which become sheathed and lead to multiple stenoses or even occlusions. Subclavian steal syndrome (SSS) has not been reported in ECD. A 68-year-old female was diagnosed with ECD due to the typical sheathing of the aorta and its major branches. Five years previously, asymptomatic SSS due to stenosis of the left subclavian artery was incidentally diagnosed. In the following years, occlusion of the subclavian and left vertebral artery, and stenosis of basilar artery and right middle cerebral artery occurred. The abnormal cerebral perfusion had consequences on the perfusion of the left upper extremity and was presumably responsible for falls. Basilar and middle cerebral artery stenosis is rare in ECD and vertebral artery occlusion and double subclavian steal have not been reported in ECD. This case is the first to show that the initial manifestation of ECD can be unilateral SSS and that subclavian artery occlusion can even lead to double SSS. Patients with SSS should undergo a thorough diagnostic evaluation to detect rare causes of SSS, such as ECD.

Erdheim-Chester Disease with Renal Mass Presentation: Report of the First Case From Palestine and a Review of the Literature

BACKGROUND Erdheim-Chester disease (ECD), a form of non-Langerhans-cell histiocytosis, is extremely rare. The mean age of individuals with ECD is in their 50s. Histiocytic infiltration of vital organ systems is a potential cause of substantial morbidity, which is associated with the multisystemic form of ECD. This report presents the first case of ECD with renal abnormalities in Palestine. CASE REPORT A 54-year-old woman with no medical or surgical history presented with 6 months of bilateral flank pain with no radiation or fever. A physical examination revealed only bilateral flank pain. Urine tests showed microhematuria. Laboratory test results showed increased serum creatinine levels (1.21 mg/dL) and microcytic anemia. A CT scan revealed significant multi-organ abnormalities, including renal abnormalities with a hairy kidney sign, pericardial effusion, and an osteolytic lesion of the spine. The hairy kidney sign is pathognomonic for ECD, so the renal mass was biopsied to confirm the diagnosis. The biopsy showed foamy histiocytes, lymphocytes, and plasma cells. Foamy histiocytes were CD68-positive and negative for S100, CD1a, and HMB45. PAx5 and CD3 immunostaining showed T-predominant B-lymphocyte mixtures. CONCLUSIONS In the setting of systemic symptoms and imaging abnormalities such as presence of the hairy kidney sign, pericardial effusion, and osteolytic lesion of the spine, it is necessary to examine the possibility of ECD and proceed with a biopsy for confirmation. This is the first case in Palestine to be reported and the second case worldwide with a renal mass as an atypical presentation.

Erdheim-Chester disease presenting as meningitis with hypoglycorrhachia: A case report

INTRODUCTION

Erdheim-Chester disease (ECD) commonly has neurologic manifestations but rarely presents with meningitis and hypoglycorrhachia. Here, were present a case of ECD with a clinical and laboratory presentation initially thought to be bacterial meningitis with sepsis.

METHODS

We report a case of a 79-year-old with history of enigmatic bone pain and peritoneal nodules who presented with meningitis. After failure to improve on antibiotic therapy other etiologies of hypoglycorrhachia including sarcoid, tuberculosis, and fungal and carcinomatous meningitis were considered. However, no definite diagnosis could be made based on radiologic, serologic, microbiologic, and molecular testing and the patient failed to improve on empiric therapy including antibiotics, antifungals, and tuberculosis and steroid therapy.

RESULTS

Ultimately, autopsy revealed a new diagnosis of ECD manifesting as meningitis, a rare presentation of a rare disease.

CONCLUSION

Although only reported in one other case to our knowledge, ECD can present with meningitis with hypoglycorrhachia.

Characteristics, outcome and treatments with cranial pachymeningitis: A multicenter French retrospective study of 60 patients

The aim of this study was to determine the characteristics, treatment, and outcome according to each etiology of pachymeningitis.We conducted a retrospective multicenter French nationwide study between 2000 and 2016 to describe the characteristics, outcome, and treatment of pachymeningitis.We included 60 patients (median age 55.5 years; interquartile range [IQR] 30-80, female/male ratio 0.43). Neurologic signs were present in 59 patients (98%) and consisted of headache in 43 (72%), cranial nerve palsy in 33 (55%), confusion in 10 (17%), seizures in 7 (12%), and focal neurologic signs in 9 (15%). Fever and weight loss were present in 8 (13%) and 13 cases (22%), respectively. Cerebral venous thrombosis was present in 8 cases (13%). Analysis of cerebrospinal fluid showed moderate hyperproteinorachia (median 0.68 g/L; IQR 0.46-3.2) with or without pleiocytosis. Diagnosis included idiopathic pachymeningitis (n = 18; 30%); granulomatosis with polyangiitis (n = 13; 17%); Erdheim-Chester disease (n = 10; 17%); IgG4-related disease and tuberculosis (n = 3; 5% each); Rosai-Dofman disease, microscopic polyangiitis, and sarcoidosis (n = 2, 3% each); cryptococcal meningitis, Lyme disease, ear-nose-throat infection, postlumbar puncture, low spinal-fluid pressure syndrome, and lymphoma (n = 1 each). We found no difference in demographics and neurologic presentation among idiopathic pachymeningitis, Erdheim-Chester disease, and granulomatosis with polyangiitis. In contrast, frequencies were lower with idiopathic pachymeningitis than Erdheim-Chester disease for general signs (6% and 40%, respectively, P = .041) and complete neurologic response (0% vs 39%, P = .045).The detection of extraneurologic signs and routine screening are needed to classify the pachymeningitis origin. Prospective studies are warranted to determine the best treatment in each case.

Quantification of tumor-derived cell free DNA(cfDNA) by digital PCR (DigPCR) in cerebrospinal fluid of patients with BRAFV600 mutated malignancies

Tumor-derived cell free DNA (cfDNA) can be detected in plasma. We hypothesized that mutated BRAF V600 cfDNA could be quantified in the cerebrospinal fluid (CSF) of patients with central nervous system (CNS) metastases. We collected CSF from patients with BRAF V600E or K-mutated melanoma (N=8) or BRAF V600E mutated Erdheim-Chester Disease (ECD) (N=3) with suspected central nervous system (CNS) involvement on the basis of neurological symptoms (10/11), MRI imaging (8/11), or both. Tumor-derived cfDNA was quantified by digital PCR in the CSF of 6/11 patients (range from 0.15-10.56 copies/μL). Conventional cytology was negative in all patients except in the two patients with markedly elevated levels of tumor-derived cfDNA. In 2 patients with serial measurements, CSF tumor-derived cfDNA levels reflected response to treatment or progressive disease. CSF tumor-derived cfDNA has the potential to serve as a diagnostic tool that complements MRI and may be more sensitive than conventional cytology.

A Case of Incidentally-diagnosed Erdheim-Chester Disease

Erdheim-Chester disease (ECD) is a rare multisystemic non-Langerhans cell histiocytosis that may be clonal and inflammatory in origin. The hallmark of the disease is infiltration of various organ systems by CD68+/CD1a- histiocytes containing foamy lipid-laden inclusions. The manifestations and course of the disease are variable and depend on the organ systems that are affected. Patients may be asymptomatic or may develop life-threatening complications, including myocardial infarction. The most common clinical manifestation is lower extremity bone pain. Imaging manifestations of the disease include symmetric osteosclerosis of the distal long bones, circumferentially “coated” aorta, pleural and pericardial thickening/fluid, and perirenal encasement. Treatment for the disease is evolving, particularly with the use of molecular BRAF inhibition. We present a case of a patient with ECD initially suspected based on the imaging manifestations.