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

Erdheim-Chester disease: diffusion-weighted imaging and dynamic contrast-enhanced MRI provide useful information

This is, to our knowledge, the first case report with in-depth analysis of bone marrow and bone lesions with diffusion-weighted imaging and dynamic contrast-enhanced MRI in Erdheim-Chester disease to date. We present a case of a 70-year-old woman who was referred for an X-ray of the pelvis, right femur and right knee after complaints of migratory arthralgia in hip and knee five months after an initial hip and knee trauma. Bone lesions on X-ray were identified. This case report highlights the strength and complementary use of modern multimodality multiparametric imaging techniques in the clinical radiological manifestations of Erdheim-Chester disease, in the differential diagnosis and in treatment response assessment, which is classically performed using ¹⁸FDG PET-CT. Erdheim-Chester disease is a rare form of non-Langerhans' cell histiocytosis, mainly affecting individuals in their fifth-seventh decade of life and without sex predominance. Apart from the typical bilateral symmetric lesions in long bone diaphyseal and metaphyseal regions and classically sparing the epiphyses, this multisystemic disease causes significant morbidity by infiltrating critical organs (the central nervous system, cardiovascular system, retroperitoneum, lungs and skin). With non-traumatic bone pain being the most common complaint, Erdheim-Chester disease is diagnosed most often in an incidental setting on imaging. The imaging workup classically consists of a multimodality approach using conventional radiography, CT, MRI, bone scintigraphy and ¹⁸FDG PET-CT. This case report extends this evaluation with diffusion-weighted imaging and dynamic contrast-enhanced imaging techniques.

Clinical phenotypes and long-term outcome of kidney involvement in Erdheim-Chester histiocytosis

Erdheim-Chester disease (ECD) is a rare non-Langerhans cell histiocytosis that frequently infiltrates the peri-kidney space ("hairy kidney" appearance), kidney pelvis and proximal ureters, leading to obstructive uropathy. Here, we analyzed the clinical characteristics, imaging findings and long-term kidney outcome of a large multicenter cohort comprising 195 consecutive patients with ECD. Retroperitoneal peri-kidney or peri-ureteral involvement was detected at diagnosis in 147 patients. Of them, 70 had hydronephrosis (bilateral in 47), and 16 with kidney atrophy (unilateral in 14). Kidney vascular peduncle infiltration was found in 60 patients, and kidney artery stenosis in 31. The estimated glomerular filtration rate (eGFR) at diagnosis was significantly lower in patients with than in those without peri-kidney involvement (median 74 vs. 98 mL/min/1.73 m²). Ureteral stenting often failed to achieve kidney function recovery. A total of 181 patients received medical therapies: first-line treatments included interferon-α (61%), BRAF-inhibitors (17%), mTOR-inhibitors (7%), or other drugs (15%). These therapies were efficacious for ECD but rarely induced kidney function improvement (one-year eGFR increase over 25% in under 10% of patients). After a median of 43 months, 19% of patients died and 5% developed kidney failure. Among patients with peri-kidney involvement, 44% developed chronic kidney disease (CKD) 3-5 at five years vs. 5% of those without. Unadjusted predictors of advanced CKD and kidney failure/death were age over 50 years, hypertension, BRAFV600E mutation, and baseline eGFR. At multivariable analysis, cardiovascular comorbidities were associated with advanced CKD, and age over 50 years with kidney failure/death. Thus, kidney involvement is common in ECD and can lead to CKD or kidney failure despite effective medical therapies or urological procedures.

Rosai-Dorfman Disease between Proliferation and Neoplasia

Rosai-Dorfman disease (RDD) is a rare myeloproliferative disorder of histiocytes with a broad spectrum of clinical manifestations and peculiar morphologic features (accumulation of histiocytes with emperipolesis). Typically, the patient with RDD shows bilateral painless, massive cervical lymphadenopathy associated with B symptoms. Approximately 43% of patients presented with extranodal involvement. According to the 2016 revised histiocytosis classification, RDD belongs to the R group, including familial and sporadic form (classical nodal, extranodal, unclassified, or RDD associated with neoplasia or immune disease). Sporadic RDD is often self-limited. Most RDD needs only local therapies. Nevertheless, a small subpopulation of patients may be refractory to conventional therapy and die of the disease. Recent studies consider RDD a clonal neoplastic process, as approximately 1/3 of these patients harbor gene mutations involving the MAPK/ERK pathway, e.g., NRAS, KRAS, MAP2K1, and, rarely, the BRAF mutation. In addition to typical histiocytic markers (S100/fascin/CD68/CD163, etc.), recent studies show that the histiocytes in RDD also express BCL-1 and OCT2, which might be important in pathogenesis. Additionally, the heterozygous germline mutation involving the FAS gene TNFRSF6 is identified in some RDD patients with an autoimmune lymphoproliferative syndrome type Ia. SLC29A3 germline mutation is associated with familial or Faisalabad histiocytosis and H syndrome.

Treatment-Refractory Nodular Scleritis

A 59-year-old woman with a 5-year history of intermittent bilateral uveitis and scleritis presented with painful left uveitis and an episcleral nodule shown to be a uveal-episcleral lesion on ultrasound biomicroscopy. Biopsy of a nasal sinus mass 3 years earlier showed a histiocytic infiltrate with emperipolesis, consistent with Rosai-Dorfman-Destombes disease. What would you do next?

Erdheim-Chester Disease Involving the Central Nervous System with Latent Toxoplasmosis

Erdheim-Chester disease (ECD) is a rare, non-Langerhans cell histiocytosis characterized by the infiltration of foamy histiocytes into multiple organs. We herein report a case of ECD with central nervous system (CNS) involvement in a 63-year-old man who also presented a positive result for Toxoplasma gondii nested polymerase chain reaction testing of cerebrospinal fluid. Since anti-Toxoplasma treatment proved completely ineffective, we presumed latent infection of the CNS with T. gondii. This case suggests the difficulty of distinguishing ECD with CNS involvement from toxoplasmic encephalitis and the possibility of a relationship between the pathogeneses of ECD and infection with T. gondii.

Genetics and clinical phenotype of Erdheim–Chester disease: A case report of constrictive pericarditis and a systematic review of the literature

Background

Erdheim–Chester disease (ECD) is a rare form of histiocytosis. An increasing number of genetic mutations have been associated with this syndrome, confirming its possible neoplastic origin. Recently, a connection between the BRAF mutational status and a specific phenotype was described; however, no studies have yet evaluated the correlations between other mutations and the clinical features of the disease.

Objectives

This study aims to clarify the association between the clinical phenotype and genetic mutations identified in the neoplastic cell lines of ECD.

Methods

We describe a case of ECD characterized by pericardial involvement and a KRAS mutation shared with chronic myelomonocytic leukemia. Hence, through a meta-analysis of individual participant data of all genetically and clinically described cases of ECD in the literature, we aimed to elucidate the association between its clinical phenotype and baseline genetic mutations.

Results

Of the 760 studies screened, our review included 133 articles published from 2012 to April 2021. We identified 311 ECD patients whose genotype and phenotype were described. We found five main genes (BRAF, KRAS, NRAS, PIK3CA, and MAP2K1) whose mutation was reported at least three times. Mutation of BRAF led to a neurological disease (183 of 273 patients, 67%; p < 0.001); KRAS- and NRAS-mutated patients mainly showed cutaneous (five of six patients, 83.3%, p < 0.004) and pleural (four of nine patients, 44%, p = 0.002) involvement, respectively; PIK3CA was not associated with specific organ involvement; and MAP2K1 mutations caused the disease to primarily involve the peritoneum and retroperitoneum (4 of 11, 36.4%, p = 0.01).

Conclusion

This work implies a possible influence of baseline mutation over the natural history of ECD, underscoring the importance of a thorough genetic analysis in all cases with the ultimate goal of identifying a possible targeted therapy for each patient.

FDG PET/CT in Mixed Langerhans Cell Histiocytosis and Erdheim-Chester Disease

ABSTRACT

The histiocytoses arise from hematopoietic bone marrow stem cells or monocytes. They range from limited to disseminated disease. We report a 31-year-old woman with multisystem Langerhans cell histiocytosis (LCH). The recognition that pericardial disease was rare in LCH prompted review of the initial limited biopsies, which helped establish a second diagnosis of Erdheim-Chester disease. The increasing recognition of mixed histiocytoses requires searching for Erdheim-Chester disease when a patient is diagnosed with LCH and vice versa. FDG PET/CT can help establish the diagnosis or suggest mixed disease based on the organs involved.

A rare case of Erdheim-chester disease reported from Nepal

Introduction

Erdheim-Chester Disease (ECD) is a rare non-Langerhans cell histiocytosis with a propensity to involve multiple organs.

Case presentation

We report a case of a patient in mid-60s with occipital headache and ataxia. Following the radiological and immunohistochemical investigations and genomic studies, a diagnosis of ECD was made with two intracerebral lesions. Brain lesions were resected and the patient was discharged with the medication Vemurafenib. After 3 years of diagnosis and 13 years of initial presentation, patient passed away.

Discussion

ECD frequently presents with Diabetes Insipidus as initial presentation, long bone osteosclerosis as the most common presentation, and has multi-system predisposition. ECD can be differentiated from Langerhans Cell Histiocytosis (LCH) with immunohistochemistry images of the biopsy specimens. Further, with genomic analysis of ECD, the neoplastic nature has been highlighted and targeted therapies like Vemurafenib and Cobimetinib are shown to be effective.

Conclusion

Good clinical judgement and supporting investigations can aid in diagnosing rare entities like ECD even in resource-limited settings.

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Rare case of Erdheim-Chester disease with multi-system involvement presenting with initial features 10 years prior to diagnosis.

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Initially Diabetes Insipidus, followed by long bone and other multi-system involvement important cues for the diagnosis.

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Biopsy of the lesion and immunohistochemical analysis can help confirm the diagnosis.

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Genomic studies with mutational analysis further highlights the neoplastic nature of the disease.

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Advancement of genomic studies with targeted therapies like Vemurafenib and Cobimetinib key in of management of ECD.

Pancreatic involvement in Erdheim-Chester disease: a case report and review of the literature

Background

Erdheim-Chester disease (ECD) is a rare form of non-Langerhans cell histiocytosis characterized by infiltration of lipid-laden foamy macrophages within different tissues. Clinical manifestations of ECD are highly heterogeneous. Bone lesions are found in 80%-95% of patients, while extraosseous lesions usually involve the cardiovascular system, retroperitoneum, central nervous system (CNS), and skin. Pancreatic involvement in ECD has barely been reported.

Case presentation

A 29-year-old female initially presented with menoxenia, diabetes insipidus and diabetes mellitus. 18F-fluorodeoxyglucose positron emission tomography-computed tomography (18F-FDG-PET/CT) revealed hypermetabolic foci in the bilateral frontal lobe, saddle area, and pancreas. A 99mTc-MDP bone scrintigraphy scan revealed symmetrical increased uptake in distal femoral and proximal tibial metaphysis, which was confirmed to be osteosclerosis by high-resolution peripheral quantitative computed tomography. The patient underwent incomplete resection of the sellar mass. Histological examination of biopsies showed histiocytic aggregates, which were positive for S100 and negative for CD1a and CD207 on immunohistochemistry. Enhanced abdominal CT scan showed hypointense nodules within the body and tail of the pancreas. Endoscopic ultrasonography guided fine-needle aspiration (EUS-FNA) found no evidence of malignancy. She was diagnosed with ECD and treated with high-dose IFN-α. Repeated examinations at three-and eight-months post treatment revealed markedly reduction of both intracranial and pancreatic lesions.

Conclusions

ECD is a rare histiocytic neoplasm that can involve almost every organ, whereas pancreatic involvement has barely been reported to date. Here, we present the rare case of pancreatic lesions in ECD that responded well to interferon-α. We further reviewed reports of pancreatic involvement in histiocytic disorders and concluded the characteristics of such lesions to help diagnosis and treatment, in which these lesions mimicked pancreatic adenocarcinoma and caused unnecessary invasive surgeries.

Rare presentation of multiple thromboses in Erdheim-Chester disease: a case-based review

BACKGROUND

ECD is a rare non-Langerhans cell histiocytosis with diverse and heterogeneous clinical manifestations, ranging from single-lesion forms to multi-system involvement, including slowly progressing unifocal forms to rapidly evolving life-threatening disease.

CASE PRESENTATION

A female patient presented with a 2-month history of fever. Imaging revealed multiple thromboses, bone destruction, an abnormal pituitary stalk, and clinical manifestations of diabetes insipidus. Excisional biopsy of a tibial lesion was sent for microscopic examination, and subsequent immunohistochemical testing was positive for expression of CD68 and CD163, and negative for expression of the immune markers CD1a, S100, and langerin. This confirmed the diagnosis of ECD. Treatment with methylprednisolone to inhibit the immune inflammatory response along with anti-cytokine therapy with an interleukin-6 antagonist resulted in satisfactory disease control.

CONCLUSION

We report a rare case of multiple thromboses, embolism, and multiple organ involvement as the main presentation of ECD, suggesting that ECD should be considered in patients presenting with multiple thromboses associated with multisystem damage. We successfully treated our patient with glucocorticoids and interleukin-6 antagonist. This patient's response to treatment suggests that hormone therapy and cytokine/chemokine therapy may be a potential novel treatment for patients with ECD without gene mutations.

Cyclin D1 expression and molecular genetic findings in periocular histiocytoses and neoplasms of macrophage-dendritic cell lineage

PURPOSE

Frequent activating mutations in the mitogen-activated protein kinase (MAPK) pathway genes have been identified in histiocytoses. MAPK signaling consistently upregulates Cyclin D1. The goal of this study was to determine whether Cyclin D1 expression by immunohistochemistry is a useful diagnostic marker for periocular histiocytoses and to further characterize their genetic basis.

DESIGN

Retrospective observational case series.

METHODS

Pathology records were searched for all patients with histiocytoses diagnosed between 1995-2020. Eleven histiocyte-rich inflammatory lesions and 10 xanthelasma served as controls. Cyclin D1 immunohistochemistry was performed on all tissues. A subset of histiocytoses was evaluated by next-generation sequencing (NGS) and droplet digital PCR (ddPCR).

RESULTS

There were 36 patients, 15 (42%) males and 21 (58%) females, with histiocytoses: 9 (25%) juvenile xanthogranuloma, 8 (22%) adult-onset asthma and periocular xanthogranuloma, 7 (19%) Langerhans cell histiocytosis, 5 (14%) Rosai-Dorfman disease, 5 (14%) xanthogranuloma not otherwise specified, 1 (3%) Erdheim-Chester disease, and 1 (3%) histiocytic sarcoma. Moderate-to-strong nuclear Cyclin D1 expression was present in ≥50% of lesional cells in histiocytoses (23/36, 64%), significantly more when compared to histiocyte-rich inflammatory lesions (0/11, 0%, P<.001) and xanthelasma (0/10, 0%, P<.001). Cyclin D1 was expressed in <10% of lesional cells in all 11 histiocyte-rich inflammatory lesions (P<.001) and all 10 xanthelasma lesions (P<.001). MAPK pathway gene mutations were detected in 12 of 14 (86%) histiocytoses successfully assayed by NGS and/or ddPCR.

CONCLUSIONS

Our study confirms that the Cyclin D1 immunohistochemical stain is a useful diagnostic marker for periocular histiocytoses, correlating with underlying mutations in MAPK pathway genes.

Erdheim-Chester Disease Revealed by Central Positional Nystagmus: A Case Report

Erdheim-Chester disease (ECD) is a rare histiocytic disorder, recently recognized to be neoplastic. The clinical phenotype of the disease is extremely heterogeneous, and depends on the affected organs, with the most frequently reported manifestations being bone pain, diabetes insipidus and neurological disorders including ataxia. In this article, we report on a case of a 48-year-old woman, whose initial symptom of gait instability was isolated. This was associated with positional nystagmus with central features: nystagmus occurring without latency, clinically present with only mild symptoms, and resistant to repositioning maneuvers. The cerebral MRI showed bilateral intra-orbital retro-ocular mass lesions surrounding the optic nerves and T2 hyperintensities in the pons and middle cerebellar peduncles. A subsequent CT scan of the chest abdomen and pelvis found a left “hairy kidney”, while ¹⁸ F-FDG PET-CT imaging disclosed symmetric 18F-FDG avidity predominant at the diametaphyseal half of both femurs. Percutaneous US-guided biopsy of perinephric infiltrates and the kidney showed infiltration by CD68(+), CD1a(-), Langerin(-), PS100(-) foamy histiocytes with BRAF^V600E mutation. The combination of the different radiological abnormalities and the result of the biopsy confirmed the diagnosis of ECD. Many clinical and radiological descriptions are available in the literature, but few authors describe vestibulo-ocular abnormalities in patients with ECD. Here, we report on a case of ECD and provide a precise description of the instability related to central positional nystagmus, which led to the diagnosis of ECD.

A Rare Case of Pediatric Xanthoma Disseminatum With Diabetes Insipidus and BRAF p.V600E Mutation

ABSTRACT

Xanthoma disseminatum (XD) is a rare non-Langerhans cell histiocytosis characterized by xanthomatous lesions in the absence of hyperlipidemia. XD usually develops in young adults, and there are rare cases among children. BRAF mutations are frequent in Langerhans cell histiocytosis and Erdheim-Chester disease but absent or only rarely detected in other histiocytosis. Herein, we described a 6-year-old Chinese girl presented with generalized skin lesions and diabetes insipidus for 5 months. There were multiple periorbital xanthelasma with histopathological features of foamy histiocytes infiltration with Touton cells. Pituitary magnetic resonance imaging showed pituitary enlargement and pituitary stalk thickening. The presence of BRAF p.V600E mutation makes this case distinctive and also offers a potential therapeutic target. According to our review of the literature, this is the first pediatric XD with diabetes insipidus and BRAF mutation.

Erdheim-Chester disease with multisystem involvement evaluated by multimodal imaging: A case report

Erdheim-Chester disease is a rare, idiopathic, multisystemic non-Langerhans cell histiocytosis. Little is known about the imaging features. Herein, we report a very uncommon case of Erdheim-Chester disease in a 54-year-old woman with multisystem involvement including cardiovascular system, skeleton, retroperitoneum (renal and adrenal infiltration), orbit and pituitary. Multimodal imaging modalities, including computed tomography, magnetic resonance imaging, echocardiography, and bone scintigraphy were used to comprehensively evaluate different organs involvement. Finally, myocardial biopsy results indicated Erdheim-Chester disease. Electrocardiography showed sick sinus syndrome and slowest heart rate of 20 beats/min. The patient underwent permanent pacemaker implantation and had initial treatment with interferon. There were no remarkable changes in right atrial lesion during 9-month follow-up period. Erdheim-Chester disease was a rare entity with a dismal prognosis, especially when there were cardiac and neurological involvement. The present case report aimed to described and analyzed radiological findings of multiple organs involvement of Erdheim-Chester disease with multimodal imaging retrospectively, and being familiar with the imaging features of Erdheim-Chester disease might help prompt and correct diagnosis of this disease in the future.

Atypical skeletal involvement in patients with Erdheim-Chester disease: CT imaging findings

Objectives

To review retrospectively atypical bone findings from computed tomographic (CT) imaging in patients with Erdheim–Chester disease.

Methods

All 28 patients with Erdheim–Chester disease (13 men and 15 women; mean age, 45 years; range, 7–63 years) underwent chest-abdomen-pelvis CT. CT images were reviewed and analyzed for the various features of atypical bone lesions by two radiologists in consensus.

Results

Twenty-one patients had atypical bone involvement. Radiologically, these atypical osseous lesions were categorized into three types: diffuse, nodular and patchy. Eleven (52%) of the 21 patients had spinal lesions, of which four (36%) had the diffuse type, eight (73%) had the nodular pattern, and six (55%) had the patchy pattern. Sixteen (76%) of the 21 patients had pelvic involvement, of which two (13%) were diffuse, nine (56%) were nodular and 11 were (69%) patchy. Ribs were involved in seven (33%) of the 21 patients, with the nodular pattern in one (14%) patient and the patchy type in six (86%) patients. Clavicle involvement was seen in nine (43%) of the 21 patients, of which the diffuse type was found in only one (11%) patient, the nodular type in six (67%) patients, the solitary patchy type in four (44%) patients. Sternum involvement was seen in 10 (48%) of the 21 patients and all were nodular.

Conclusions

This series provides a detailed description of atypical bone involvement in Erdheim–Chester disease which on CT displays three major patterns. Understanding these patterns may help increase the accuracy of diagnosis of this disease.

Endoscopic Transsphenoidal Resection of Suprasellar Histiocytosis in a Patient with Erdheim-Chester Disease: A Case Report

Erdheim–Chester disease (ECD) is a rare systemic disease characterized by non-Langerhans histiocytosis. Pituitary involvement, often manifesting as diabetes insipidus, is the most common central nervous system (CNS) lesion. However, significant mass formation compressing the optic apparatus is rarely reported. We present a case of ECD-related suprasellar mass treated with an endoscopic transnasal approach, with emphasis on the surgical strategy and the intraoperative findings. The mass was fibrous, significantly hard, and strongly adhered to the optic nerves, causing visual impairment. A subtotal resection was performed with preserving the adhesion between the mass and the optic nerves, and her visual symptoms improved remarkably after surgery. We highlight the surgical procedure of ECD-related suprasellar mass, from an endoscopic point of view. Due to strong adhesion of the mass to the surrounding optic apparatus and perforators, complete resection may be harmful; judicious mass reduction with preserving such adhesion would contribute to better visual outcomes.

A long-term survival case of Erdheim-Chester disease on maintenance hemodialysis

Erdheim-Chester disease, a rare non-Langerhans histiocytosis, involves multiple organs, including kidney. Renal dysfunction sometimes occurs, and is attributed to ureteral obstruction and renal artery stenosis by histiocytic infiltration. However, to our knowledge, case reports of end-stage renal disease requiring renal replacement therapy due to Erdheim-Chester disease are very few. Here, we report a 69-year-old woman who was diagnosed with Erdheim-Chester disease 10 years ago. She had multiple organ involvement, such as bone, skin, heart, pituitary gland, kidney, and retroperitoneum. She had been treated with interferon-alpha, but discontinued after 2 years due to depression and repeated infection. She did not desire treatment with other drugs, so we continued supportive care. Her renal function gradually deteriorated, and hemodialysis was initiated 4 years ago. Subsequently, she is still doing well without any major symptoms. This report describes an unusual case of Erdheim-Chester disease requiring maintenance hemodialysis that longer prognosis than expected was obtained regardless of multiple organ involvement and no specific treatment after interferon-alpha cessation.

Erdheim Chester Disease - Unusual Presentation with Isolated Skeletal Lytic Lesions

Introduction

Erdheim-Chester disease (ECD) is a rare non-Langerhans cell histiocytosis (LCH) of unknown origin that was first described in 1930. Since then, almost 600 cases have been reported worldwide. Even though this disease primarily affects the bone, it has a varied clinical spectrum of presentation ranging from asymptomatic bone lesions to multisystem involvement. Owing to its protean manifestations ECD is often misdiagnosed or diagnosed late.

Case Report

We present a 48-year-old female with a long long-standing history of recurrent bone lesion of the tibia and multiple trivial trauma fractures of long bones. Recently, she also developed a persistent headache and painful swelling of the right shoulder and left hip joint. Radiographs revealed multiple lytic and lytic sclerotic lesions. With the probable diagnosis of LCH, she underwent biopsy which revealed features characteristic of ECD.

Conclusion

This case highlights the fact that histopathological confirmation is the key to distinguish various types of histiocytic neoplasms. Overlapping clinical and radiological features with atypical manifestations can occur in both LCH and ECD and does not rule out either of them.

Solitary Radiolucent Erdheim-chester Disease: A Case Report and Literature Review

Background:

Erdheim-chester disease (ECD) is a rare non-Langerhans histiocytosis of unknown etiology, which typically presents with bilateral symmetric osteosclerosis and multi-organ involvement. Lesions may be intraosseous or extraosseous and involve the heart, pulmonary system, CNS, and skin in order of decreasing likelihood.

Objective:

The objective of this study is to discuss a case of erdheim-chester disease and conduct a review of the literature.

Case:

We describe a rare case of erdheim-chester in an asymptomatic 37-year-old male who was diagnosed after suffering a right ulnar injury. Subsequent evaluation revealed a solitary radiolucent ulnar lesion without multi-system involvement.

Results & Conclusion:

The case is unique in its solitary distribution, lytic radiographic appearance, and asymptomatic presentation preceding pathologic fracture. This presentation may simulate multiple other bone lesions.

Malignant Otitis Externa in a 20-Year-Old Male Patient With Erdheim-Chester Disease: A Case Report

Malignant otitis externa (MOE) is an uncommon, potentially life-threatening, invasive infection of the external auditory canal and lateral skull base. It is mainly seen in older adults with diabetes or immunocompromised patients and rarely seen in children.

Erdheim-Chester disease (ECD) is a rare, non-Langerhans histiocytosis disorder. It is a multisystem disease with a poorly understood etiology. It commonly affects the skeletal system, central nervous system (CNS), cardiovascular system, lungs, retroperitoneum, kidneys, and skin. CNS involvement confers poor prognosis and reduced response to treatment. Cardiovascular involvement is another indicator of poor prognosis.

This report describes the case of a 20-year-old male with ECD who had bilateral malignant otitis externa/skull base osteomyelitis and hearing loss. The patient was not responding well to treatment. He was on intravenous antibiotics, underwent left mastoidectomy, received targeted immunotherapy, and had four rounds of chemotherapy. The patient died after six months from the diagnosis and targeted treatment, which indicates the aggressiveness of the disease.

MOE should be suspected in any patient presenting with intractable otalgia with otorrhea that is not responsive to local treatment for uncomplicated otitis externa or otalgia with temporomandibular joint (TMJ) pain aggravated by chewing.

This is the first report of malignant otitis externa in a young patient with ECD to the best of the author's knowledge. This case emphasizes the importance of suspecting MOE in young patients, especially if the risk factors of the disease are present because early diagnosis can prevent or minimize life-threatening complications.

Erdheim-Chester disease: First pediatric case report in Colombia

The Erdheim-Chester’s disease is extremely rare in children. We present the case of a 12-year-old girl with histological and radiological diagnosis of this disease and mutation of the BRAF gene, who developed multisystemic compromise requiring treatment with dabrafenib. We identified 22 reports of this condition among children worldwide and this is the second pediatric case in Latin America. Diagnostic imaging is critical to confirm Erdheim-Chester disease and for the surgical planning of the biopsy. Additionally, we identified the parasellar dark sign, which has previously been reported on lymphocytic hypophysitis. This report contributes to the current practice as it shows the clinical presentation and the diagnostic workout of this disease in pediatrics.

[Granulomatous skeletal lesions]

The main granulomatous diseases of the musculoskeletal system are Langerhans cell histiocytosis, sarcoidosis, Erdheim-Chester disease (lipoidgranulomatosis) and mastocytosis. In most cases the patients have only a few symptoms, and the disease is detected coincidentally. The diagnosis is usually made by a synopsis of topographical presentation, clinical appearance and the radiological pattern (destruction, reactive new bone formation).

Utility of Cyclin D1 Immunostaining in Cutaneous Xanthogranuloma

ABSTRACT

Mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase pathway activation has recently been found to be associated with almost all Langerhans cell histiocytosis cases. In BRAF V600E mutation-positive cases, this activation is seen as a downstream activation. In addition, cyclin D1 is a downstream target of the MAPK pathway. Recent studies have argued in favor of using cyclin D1 as a potential neoplastic marker to differentiate Langerhans cell histiocytosis from other reactive Langerhans cell proliferations in the skin and lymph nodes. Therefore, we chose to study the immunohistochemical expression of cyclin D1 in cutaneous xanthogranuloma (XG) cases. Fifteen XG cases were retrieved and stained for cyclin D1, BRAF (v-raf murine sarcoma viral oncogene homolog B1), CD1a, and langerin (CD207). Twelve cases showed strong and diffuse nuclear positivity for cyclin D1, both in the XG cells and in the multinucleated osteoclast-like giant cells. Three cases showed focal weak nuclear staining for cyclin D1. All 15 cases showed negative immunoreactivity for BRAF, CD1a, and CD207. Although limited by small sample size, we conclude that most cases of cutaneous XG should show at least weak nuclear staining with cyclin D1. The histogenesis of XG is still largely unknown, and the finding of cyclin D1 positivity in a majority of cases may indicate a role for the MAPK/extracellular signal-regulated kinase pathway in cutaneous XG.

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.