Erdheim-Chester disease: clinical and pathologic spectrum of four cases from the Arkadi M. Rywlin slide seminars

Recent advances in therapeutic strategies of Erdheim-Chester disease

Erdheim-Chester disease (ECD) is a rare form of non-LCH characterized by excessive accumulation of histiocytes in various tissues, leading to significant morbidity. The estimated prevalence of ECD is low, with fewer than 1000 cases reported globally, yet it presents considerable clinical challenges due to its heterogeneous manifestations, which include bone pain, cardiovascular complications, and neurological symptoms. Traditional treatment approaches, primarily involving corticosteroids and chemotherapy, have limitations, including inconsistent responses and significant side effects. Recent advances in understanding the pathogenesis of ECD, particularly the role of the BRAF V600E mutation, have led to the exploration of novel therapeutic strategies, such as targeted BRAF inhibitors, MEK and mTOR inhibitors, and other immunotherapies, which offer promise in improving patient outcomes. The review further explores clinical manifestations, and radiographic features of Erdheim-Chester disease, and discusses treatment strategies, current clinical studies in the field of ECD. By integrating these aspects, this review aims to provide a thorough understanding of ECD and its evolving treatment landscape, ultimately contributing to improved patient outcomes.

The triptych of mixed histiocytosis: a systematic review of 105 cases and proposed clinical classification

Histiocytoses are one of the ultimate diagnostic challenges that every physician face at least once in his/her life. Giving their protean manifestation and differentiated therapeutic needs, histiocytosis requires extensive characterization and multidisciplinary management. Mixed histiocytosis is an emerging group of syndromes defined by the overlap of Langerhans cell histiocytosis and another histiocytic disorder of different type. Despite rare, it may account for up to a fifth of systemic histiocytosis patients in some series. In this work, we comprehensively review for the first time the clinical, radiological, histopathological and molecular features of mixed histiocytosis in children and adults. Moreover, we propose a clinical classification in three groups that differentiate patients with systemic involvement and worse overall survival to other groups with more localized manifestations and indolent behavior, wanting to ease their recognition and treatment. Interestingly we also found that mixed histiocytosis harbor BRAFV600E mutations with a higher frequency comparing to all other histiocytoses, and may therefore benefit of specific inhibitory drugs.

Neurologic and oncologic features of Erdheim-Chester disease: a 30-patient series

BACKGROUND

Erdheim-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.

METHODS

We present retrospective clinical, radiographic, pathologic, molecular, and treatment data from 30 patients with ECD neurohistiocytic involvement treated at a tertiary center.

RESULTS

Median 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.

CONCLUSIONS

These 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.

Skull Base Manifestations of Erdheim-Chester Disease: A Case Series and Systematic Review

BACKGROUND

Erdheim-Chester disease (ECD) is a rare, non-Langerhans cell histiocytosis. Up to 50% of patients develop central nervous system involvement, and a subset of these patients can present with isolated tumor-like masses.

OBJECTIVE

To describe the skull base manifestations of ECD with an emphasis on aspects most pertinent to surgeons who may be referred such patients for primary evaluation.

METHODS

Scopus, Web of Science, and PubMed were searched from database inception to May 1, 2018 for articles reporting skull base ECD. An institutional retrospective analysis of all patients treated at the authors’ institution since January 1, 1996 was also performed to supplement these data.

RESULTS

Of 465 retrieved articles, 18 studies totaling 20 patients met inclusion criteria. Institutional review identified an additional 7 patients. Collectively, the median age at diagnosis was 49 yr (interquartile range, 42-58) with a 4:1 male-to-female ratio. Patients frequently presented with diplopia (48%), headache (30%), dysarthria (22%), and vertigo or imbalance (22%), though trigeminal hypesthesia (11%), facial nerve paresis (7%), hearing loss (7%), and trigeminal neuralgia (7%) were also observed. ECD commonly mimicked meningioma (33%), trigeminal schwannoma (8%), neurosarcoidosis (8%), and skull base lymphoma (8%).

CONCLUSION

Discrete skull base lesions frequently mimic more common pathology such as meningioma or cranial nerve schwannomas. Medical therapy comprises the initial treatment for symptomatic skull base disease. Surgical resection is not curative and the utility of surgical intervention is largely limited to biopsy to establish diagnosis and/or surgical debulking to relieve mass effect.

The role of macrophages in interstitial lung diseases

The finding of collections of macrophages/histiocytes in lung biopsy and bronchoalveolar lavage is relatively common in routine practice. This morphological feature in itself is pathological, but the exact clinical significance and underlying disease should be evaluated together with clinical data, functional respiratory and laboratory tests and imaging studies.

Morphological characteristics of macrophages and their distribution along the different pulmonary structures should be examined carefully by pathologists. Indeed, haemosiderin-laden macrophages are associated with smoking-related diseases when pigment is fine and distribution is bronchiolocentric, while alveolar haemorrhage or pneumoconiosis are the main concerns when pigment is chunky or coarse and the macrophages show an intra-alveolar or perilymphatic location, respectively. In the same way, pulmonary accumulation of macrophages with foamy cytoplasm is generally associated with pathologies leading to broncho-bronchiolar obstruction (e.g.diffuse panbronchiolitis, hypersensitivity pneumonia or cryptogenic organising pneumonia) or alternatively to exogenous lipoid pneumonia, some drug toxicity (e.g.amiodarone exposure or toxicity) and metabolic disorders (e.g.type B Niemann–Pick disease).

This pathology-based perspectives article is aimed at concisely describing the diagnostic possibilities when faced with collection of macrophages in lung biopsy and cytology.

Role of (99m)Tc-MDP bone scan in the diagnosis of Erdheim-Chester disease

Erdheim–Chester disease (ECD) is a rare systemic non-Langerhans cell histiocytosis. It is a progressive disease of unknown etiology. The ^99mtechnetium-methylene diphosphonate (^99mTc-MDP) bone scan is useful in finding the sites of involvement in the skeleton and is helpful in excluding other causes of bony pain. Also a scintigraphic pattern consistent with ECD should alert the physician to evaluate the patient for visceral sites of involvement using fludeoxyglucose positron emission tomography/computed tomography (FDG PET/CT), as this is known to be fatal at times.

Association of both Langerhans cell histiocytosis and Erdheim-Chester disease linked to the BRAFV600E mutation

Histiocytoses are a group of heterogeneous diseases that mostly comprise Langerhans cell histiocytosis (LCH) and non-LCH. The association of LCH with non-LCH is exceptional. We report 23 patients with biopsy-proven LCH associated with Erdheim-Chester disease (ECD) (mixed histiocytosis) and discuss the significance of this association. We compare the clinical phenotypes of these patients with those of 56 patients with isolated LCH and 53 patients with isolated ECD. The average age at diagnosis was 43 years. ECD followed (n = 12) or was diagnosed simultaneously with (n = 11) but never preceded LCH. Although heterogeneous, the phenotype of patients with mixed histiocytosis was closer to that of isolated ECD than to that of isolated LCH (principal component analysis). LCH and ECD improved in response to interferon alpha-2a treatment in only 50% of patients (8 of 16). We found the BRAF(V600E) mutation in 11 (69%) of 16 LCH lesions and in 9 (82%) of 11 ECD lesions. Eight patients had mutations in both ECD and LCH biopsies. Our findings indicate that the association of LCH and ECD is not fortuitous and suggest a link between these diseases involving the BRAF(V600E) mutation.

[Imaging features of osseous and extra-osseous involvement in Erdheim-Chester disease]

Erdheim-Chester disease is a rare form of systemic non-Langerhans cell histiocytosis characterized by infiltration by lipid-laden or foamy histiocytes. Osseous involvement, major diagnostic criteria, is constant and characteristic. It presents as metaphyseal and diaphyseal osteosclerosis, mainly affecting the long bones of the lower limbs. A few cases with axial skeleton involvement have been reported. Extra-osseous lesions may affect the retroperitoneum, lungs, skin, heart, brain and orbits. Prognosis depends mainly on the extra-osseous disease, mainly heart and lung involvement. Diagnosis is based on the combination of radiographic features, nuclear medicine features and nearly pathognomonic immunohistochemical profile.

Rationale and efficacy of interleukin-1 targeting in Erdheim-Chester disease

Erdheim-Chester disease (ECD) pathophysiology remains largely unknown. Its treatment is not codified and usually disappointing. Interferon (IFN)-α therapy lacks efficacy for some life-threatening manifestations and has a poor tolerance profile. Because interleukin (IL)-1Ra synthesis is naturally induced after stimulation by IFN-α, we hypothesized that recombinant IL-1Ra (anakinra) might have some efficacy in ECD. We treated 2 patients who had poor tolerance or contraindication to IFN-α with anakinra as a rescue therapy and measured their serum C-reactive protein, IL-1β, IL-6, and monocytic membranous IL-1α (mIL-1α) levels before, under, and after therapy. Another untreated ECD patient and 5 healthy subjects were enrolled as controls. After treatment, fever and bone pains rapidly disappeared in both patients, as well as eyelid involvement in one patient. In addition, retroperitoneal fibrosis completely or partially regressed, and C-reactive protein, IL-6, and mIL-1α levels decreased to within the normal and control range. Beside injection-site reactions, no adverse event was reported. Therefore, our results support a central role of the IL-1 network, which seemed to be overstimulated in ECD. Its specific blockade using anakinra thereby opens new pathophysiology and therapeutic perspectives in ECD.

Erdheim-Chester disease: a rare syndrome with a characteristic bone scintigraphy pattern

Erdheim-Chester disease is a rare noninherited, non-Langerhans' cell histiocytosis, with multiorgan involvement. The skeleton is frequently involved in as many as 70-80% of all cases. In nearly half of the cases, there is an involvement of other organs such as the cardiovascular system, lung, kidneys, brain, and orbits. Extra-skeletal involvement is correlated with increased morbidity and mortality. In recent years, the disease is being described with increasing frequency although fewer than 200 cases have been identified worldwide. Besides its rarity, the disease has a characteristic almost pathognomonic bone scan appearance, which in some cases facilitates diagnosis of the syndrome. Bone scans also contribute to the qualitative assessment of skeletal involvement.

Unusual variants of non-Langerhans cell histiocytoses

Histiocytic syndromes represent a large, heterogeneous group of diseases resulting from proliferation of histiocytes. In addition to the classic variants, the subset of non-Langerhans cell histiocytoses comprises rare entities that have more recently been described. These last include both forms that affect only the skin or the skin and mucous membranes, and usually show a benign clinical behavior, and forms involving also internal organs, which may follow an aggressive course. The goal of this review is to outline the clinical, histologic, and ultrastructural features and the course, prognosis, and management of these unusual histiocytic syndromes.

Maladie d'Erdheim-Chester

Erdheim-Chester disease is a non-Langerhans cell histiocytosis, classically thought to be rare, but diagnosed more frequently nowadays (250 published cases). Histiocytes of Erdheim-Chester disease are positive for CD68 but not for CD1a, contrary to Langerhans cell histiocytosis. Two signs highly evocative of this diagnosis are nearly constant tracer uptake by the long bones on (99)Tc bone scintigraphy and a "hairy kidney" appearance on abdominal CT scan. A more "elegant" diagnostic method is ultrasound-guided biopsy of the perirenal infiltration. Cardiovascular involvement, which affects the aorta ("coated aorta") as well as all the cardiac layers, leads to one third of the deaths related to this disease. Central nervous system infiltration (especially cerebellar) is severe and difficult to treat. The prognosis is extremely variable and is often worse when there is a cardiovascular and/or central nervous system involvement. The treatment, decided upon on a case-by-case basis at a specialist center, often begins with interferon alpha.

Neurological manifestations and neuroradiological presentation of Erdheim-Chester disease: report of 6 cases and systematic review of the literature

Erdheim-Chester disease (ECD) is a rare, non-Langerhans form of histiocytosis of unknown etiology that affects multiple organs. We report 6 cases of ECD with neurological involvement and neuroradiological abnormalities on brain MRI. A literature review revealed 60 other cases of ECD with neurological involvement. We therefore analyzed 66 ECD patients with neurological involvement. Cerebellar and pyramidal syndromes were the most frequent clinical manifestations (41% and 45% of cases), but seizures, headaches, neuropsychiatric or cognitive troubles, sensory disturbances, cranial nerve paralysis or asymptomatic lesions were also reported. Neurological manifestations were always associated with other organ involvement, especially of bones (at least 86%) and diabetes insipidus (47%). Neurological involvement was responsible for severe functional handicaps in almost all patients and was responsible for the death of 6 of the 66 patients (9%). Neuroradiological findings could be separated into three patterns: the infiltrative pattern (44%), with widespread lesions, nodules or intracerebral masses, the meningeal pattern (37%), with either thickening of the dura mater or meningioma-like tumors, and the composite pattern (19%), with both infiltrative and meningeal lesions.

Successful treatment of Erdheim-Chester disease, a non–Langerhans-cell histiocytosis, with interferon-α

Erdheim-Chester disease is a rare non-Langerhans histiocytosis with multisystem involvement. To date, there is no standard treatment for this disorder, and more than half of the patients succumb within 3 years. Because interferon-α promotes the terminal differentiation of histiocytes and dendritic cells, we hypothesized that this molecule would be a useful therapy for Erdheim-Chester disease. We therefore treated 3 patients with advanced disease with interferon-α at a starting dose of 3 to 6 × 106 units, which was later reduced, during maintenance, to 1 × 106 units subcutaneous 3 times per week. Marked improvement was noted in all patients, with substantial retro-orbital disease regression within 1 month. Improvement in bone lesions, pain, diabetes insipidus, and other manifestations was gradual over many months. Responses were durable (3+ to 4.5+ years). Our observations suggest that this well-tolerated therapy has a significant effect on the course and outcome of Erdheim-Chester disease.

Renal Calculi in a Patient with Erdheim–Chester Disease

Erdheim-Chester Disease (ECD) is a non-inherited multifocal lipid storing histiocytosis. It is a rare disease characterised by lipid-laden monocyte infiltration of long bones causing cortical sclerosis and characteristic X-ray appearances. It also involves extraskeletal tissue in up to 50% of cases including retroperitoneal and renal infiltration. We report a patient with long standing ECD with widespread extraskeletal involvement, including significant renal infiltration, presenting with left hydronephrosis secondery obstruction from a proximal ureteric calculas.

Pulmonary and ophthalmic involvement with Erdheim-Chester disease: a case report and review of the literature

Erdheim-Chester disease is a rare nonfamilial histiocytic disorder of unknown etiology with characteristic long bone findings. The 3-year survival rate for patients with Erdheim-Chester disease is 50%. Approximately 50% of patients have disease involvement in other tissues, including skin, retro-orbital and periorbital tissues, pituitary-hypothalamic axis, heart, kidney, retroperitoneum, breast, skeletal muscle, and sinonasal mucosa; about 20% of patients have lung involvement. Prognosis generally depends on the extent of the extraosseous disease. For patients with lung involvement, gender distribution is equal, but men typically present at an older age than do women. Approximately 80% of patients present with dyspnea, and most patients have diffuse interstitial infiltrates and pleural and/or interlobar septal thickening on chest radiology. Characteristic lung histopathology includes the accumulation of histiocytes with variable amounts of fibrosis and a variable lymphoplasmacytic infiltrate in a lymphangitic distribution. Immunostains are diagnostically useful, showing immunopositivity for CD68 and factor XIIIa and immunonegativity for CD1a. Birbeck granules are uniformly absent ultrastructurally.

Laparoscopic biopsy and ureterolysis in Erdheim-Chester disease

Erdheim-Chester disease (ECD) is a rare, progressive, non-Langerhans cell histiocytosis that portends a poor prognosis. Misdiagnosis is common until adequate tissue analysis reveals the infiltrative histiocytic process. The disease process affects various organ systems, and effective treatment options are limited. Knowledge of the constellation of signs and symptoms associated with ECD is important to avoid misdiagnosis. We describe a patient who underwent laparoscopic bilateral ureterolysis and laparoscopic biopsy for presumed retroperitoneal fibrosis confirmed previously by percutaneous needle biopsy findings. The final pathologic diagnosis based on laparoscopic biopsy results was ECD. As evidenced by this case, ureterolysis offers little benefit to patients with ECD.

Cardiovascular involvement, an overlooked feature of Erdheim-Chester disease: report of 6 new cases and a literature review

Erdheim-Chester disease (ECD) is a rare, non-Langerhans form of histiocytosis of unknown origin. It is characterized by xanthomatous or xanthogranulomatous infiltration of tissues by spumous ("foamy") histiocytes. As of this writing, 178 cases have been reported. ECD is characterized by heterogeneous systemic manifestations. Bone pain is the most frequent symptom. About half of all patients have extraskeletal manifestations. Cardiovascular manifestations of ECD remain underestimated. We report 6 new cases of ECD associated with periaortic fibrosis. In 4 of these cases, the whole aorta had a "coated" aspect. A literature review revealed 66 cases of ECD with cardiovascular involvement. We therefore analyzed 72 ECD patients with cardiovascular involvement: 40 (55.6%) had periaortic "fibrosis," 32 (44.4%) had pericardial involvement, and 22 (30.6%) had myocardial involvement. Six had a right atrial tumor. Symptomatic valvular heart disease (3 aortic and 3 mitral regurgitations) was found in 6 patients. Nineteen patients (26.4%) had heart failure, leading to death in 8 cases. Six patients had renovascular hypertension related to perirenal artery stenosis. Data concerning follow-up were available for 58 (80.6%) patients. Of these, 35 (60.3%) patients died, confirming the severe prognosis of ECD. Cardiovascular complications were responsible for the death of 11 of the 35 patients (31.4%).

Erdheim?Chester disease of the breast associated with Langerhans-cell histiocytosis of the hard palate

We report a patient with Langerhans-cell histiocytosis (LCH) localized to the hard palate that was later proven to be associated with Erdheim-Chester disease (ECD), involving the right breast, skeleton, retroperitoneum and left orbit. The diagnosis was based on the symmetric osteosclerosis of the long bones diaphyses (tibias and fibulas), breast lump histopathological/immunohistochemical findings and retroperitoneum and left orbit images in magnetic resonance. Mammary involvement by ECD is an extremely rare condition, which should be differentiated from some benign and malignant mimickers, especially the histiocytoid type of breast carcinoma. Characteristic histological features plus clinical and radiographic information are needed to achieve a correct diagnosis. The ECD, its relation to the LCH and details of the breast lesion are discussed.