Erdheim-Chester disease in childhood: a challenging diagnosis and treatment

Radiological assessment of extremity bone involvement in Erdheim-Chester disease: a systematic review of case reports

OBJECTIVE

To describe the clinical presentations and radiological manifestations of Erdheim-Chester disease (ECD) in the extremities, with particular emphasis on radiologic findings, as radiographs are typically the initial imaging modality used in clinical practice.

METHODS

Following the PRISMA guidelines, a comprehensive systematic search was performed across Scopus, PubMed, Web of Science, and Embase databases, covering case reports from inception until August 1, 2024. Included were studies with pathologically confirmed ECD (CD68 positive and CD1a negative) that were evaluated with at least one imaging modality and provided detailed descriptions of radiological findings.

RESULTS

Out of 401 identified articles, 20 articles comprising 20 histologically confirmed cases of ECD met the inclusion criteria following screening and full-text review. Pathological reports were assessed for the presence of lipid-laden cells and Touton giant cells, which were identified in 84.2% and 75% of cases, respectively. Upper extremities were affected in 65% of cases and lower extremities in all cases. Symmetric involvement was observed in 84.6% of upper extremity cases and 84.2% of lower extremity cases. Radiological findings were categorized as pure sclerosis (53.3%) and cortical thickening (42.8%) identified as the most common findings. Clinical manifestations were assessed, with pain and swelling in the extremities being the most common symptoms, occurring in 70% of cases.

CONCLUSION

The hallmark of ECD is bilateral, symmetric diaphyseal and/or metaphyseal osteosclerosis in the long tubular bones of the lower extremities. Epiphyseal sparing is observed in more than half of the patients.

Erdheim-Chester disease: Comprehensive insights from genetic mutations to clinical manifestations and therapeutic advances

Erdheim-Chester disease (ECD) is an extremely rare non-Langerhans cell disorder that is believed to include both inflammatory and neoplastic characteristics. It is caused due to genetic mutations in proto-oncogenes like BRAF and MEK, while immunological pathways have an essential role in the onset and progression of the disease. Despite its rarity, ECD poses significant diagnostic and therapeutic challenges due to its heterogeneous clinical presentation and limited understanding of its underlying pathophysiology. Multiple organs can be affected, with the most frequent being long bones, central nervous system and retro-orbital abnormalities, pericardial and myocardial infiltration, interstitial lung disease, retroperitoneal fibrosis, and large blood vessel aberrations. Here, in this review, we comprehensively underline the current knowledge of ECD, including its epidemiology, clinical manifestations, genetics, pathophysiology, diagnostic modalities, and treatment options. By synthesizing existing literature and highlighting areas of ongoing research, this review aims to provide clinicians and researchers with a comprehensive understanding of ECD and guide future directions for improved patient care and outcomes.

Advances in Understanding and Management of Erdheim-Chester Disease

Erdheim Chester Disease (ECD) is a rare histiocytic disorder marked by infiltration of organs with CD68+ histiocytes. ECD stems from mutations of BRAF and MAP2K1 in hematopoietic stem and progenitor cells (HSPCs), which further differentiate into monocytes and histiocytes. Histopathology reveals lipid-containing histiocytes, which test positive for CD68 and CD133 in immunohistochemistry. Signs and symptoms vary and depend on the organ/s of manifestation. Definitive radiological results associated with ECD include hairy kidney, coated aorta, and cardiac pseudotumor. Treatment options primarily include anti-cytokine therapy and inhibitors of BRAF and MEK signaling.

Epidemiology and geographic clustering of Erdheim-Chester disease in Italy and France

This geoepidemiological study, performed in Italy and France, shows that Erdheim-Chester disease is increasingly diagnosed and cases cluster in specific geographic areas, namely southern Italy and central France. Disease frequency inversely correlates with the Human Development Index.

Novel paraneoplastic mechanism for cerebellar ataxia in Erdheim-Chester disease

We report a case of BRAF-mutation positive Erdheim-Chester disease presenting with a cerebellar ataxia. This is the first such case to be reported without structural MRI abnormalities but with a single intrathecally produced oligoclonal band. Now that the histiocytoses have been recharacterised as neoplastic, we speculate that the mechanism of the ataxia in our case is paraneoplastic. We highlight the importance of searching for BRAF mutations in this disease, as their presence leads to effective personalised treatments.

[Histiocytosis]

Histiocytosis is a group of rare diseases characterized by inflammation and accumulation of cells derived from monocytes and macrophages in different tissues. The symptoms are highly variable, from mild forms with involvement of a single organ to severe multisystem forms that can be life compromising. The diagnosis of histiocytosis is based on the clinic, radiological findings and pathological anatomy. A biopsy of the affected tissue is recommended in all cases as it may have therapeutic implications. During the last decade, some mutations have been identified in the affected tissue that condition activation of the MAPK/ERK and PI3K/AKT pathway, in a variable proportion depending on the type of histiocytosis. In this review we mainly focus on Langerhans Cell Histiocytosis, Erdheim-Chester Disease and Rosai-Dorfman Disease.

Pancreatic involvement in Erdheim-Chester disease: Rare presentation of a rare disease

Erdheim-Chester disease (ECD) as a rare non-Langerhans histiocytosis has various clinical manifestations. It is characterized histologically by infiltration of every organ, more commonly bone, retroperitoneum, cardiovascular and CNS systems with foamy, lipid -laden macrophage. Pancreatic involvement as a manifestation of this uncommon disease has very rarely been reported. Here we report a 73-year-old woman with ECD and pancreas involvement in CT, MRI and PET scans. We also aim to increase radiologist knowledge about considering ECD as a differential diagnosis for pancreas mass in the appropriate clinical situation.

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.

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: a rare non-Langerhans histiocytosis

A 3-year-old girl was admitted to our hospital with diabetes insipidus and a left eye proptosis. During investigation of diabetes insipidus, an extensive osteolytic mass, involving skull base and maxillo-facial bones, was revealed. Biopsy exhibited dense infiltrate of foamy histiocytes, which were positive for CD68 and CD163 and negative for CD1a and S100 confirming histopathological diagnosis of Erdheim-Chester disease. Treatment with dabrafenib was initiated, with good response and no side effects.

Erdheim-Chester disease: a comprehensive review from the ophthalmologic perspective

Erdheim-Chester disease (ECD) is a rare clonal histiocytic neoplasm with less than 1200 documented cases to date. The disease is life-threatening and difficult to recognize, although increasing awareness as well as the integration of clinical, imaging, pathology information , and genetic studies have led to a recent exponential increase in new reported cases. ECD affects multiple organs and systems, including skeletal, neurologic, and cardiovascular. Pulmonary, retroperitoneal, and cutaneous lesions have also been reported in various combinations. Until the discovery that more than half of ECD patients harbor the BRAF-V600E mutation or other mutations in the mitogen-activated protein kinase (MAPK) and RAS pathways, Interferon-a was the first-line treatment. Nowadays BRAF and MEK-inhibitors targeted therapies are the mainstay of treatment. Ophthalmologic involvement occurs in 25% -30% of ECD cases, usually in the form of orbital involvement presenting with exophthalmos and ophthalmoplegia. Other ophthalmologic manifestations include palpebral xanthelasmas, anterior uveitis and vitritis, optic disk edema, choroidal infiltration, recurrent serous retinal detachment, retinal drusen-like deposits and retinal pigment epithelial changes. ECD patients can also present with ocular symptoms as a result of adverse effects of the treatment regimens. In some cases with smoldering or protean symptoms, the emergence of eye manifestations triggered the diagnosis. Ophthalmologists have to be aware of the disease, recognize the constellation of ECD symptoms, and contribute to the diagnosis, treatment, and follow-up of ECD patients.

Erdheim-Chester disease

Erdheim-Chester disease (ECD) is characterized by the infiltration of tissues by foamy CD68+CD1a- histiocytes, with 1500 known cases since 1930. Mutations activating the MAPK pathway are found in more than 80% of patients with ECD, mainly the BRAFV600E activating mutation in 57% to 70% of cases, followed by MAP2K1 in close to 20%. The discovery of BRAF mutations and of other MAP kinase pathway alterations, as well as the co-occurrence of ECD with LCH in 15% of patients with ECD, led to the 2016 revision of the classification of histiocytoses in which LCH and ECD belong to the "L" group. Both conditions are considered inflammatory myeloid neoplasms. Ten percent of ECD cases are associated with myeloproliferative neoplasms and/or myelodysplastic syndromes. Some of the most striking signs of ECD are the long bone involvement (80%-95%), as well as the hairy kidney appearance on computed tomography scan (63%), the coated aorta (40%), and the right atrium pseudo-tumoral infiltration (36%). Central nervous system involvement is a strong prognostic factor and independent predictor of death. Interferon-α seems to be the best initial treatment of ECD. Since 2012, more than 200 patients worldwide with multisystem or refractory ECD have benefitted from highly effective therapy with BRAF and MEK inhibitors. Targeted therapies have an overall, robust, and reproducible efficacy in ECD, with no acquired resistance to date, but their use may be best reserved for the most severe manifestations of the disease, as they may be associated with serious adverse effects and as-yet-unknown long-term consequences.

Effective High-dose Interferon-α Therapy in a 13-Year-Old Girl With Erdheim-Chester Disease

Erdheim-Chester disease (ECD) is a proliferative disorder of non-Langerhans histiocytes with a higher incidence in the fifth to seventh decades and rarer occurrence in the pediatric population. Although ECD typically involves bone, it can also affect the central nervous system, cardiovascular system, retro-orbital space, retroperitoneal space, and kidneys, lungs, and skin. A 13-year-old Syrian girl who presented with multisystemic involvement was diagnosed with ECD. The B-Raf proto-oncogene V600E mutation was not detected in ECD lesions. Response to the high-dose interferon-α therapy was excellent in this pediatric patient. In this article, pediatric ECD case reports are also reviewed.

A case of Erdheim-Chester disease initially mistaken for retroperitoneal lymphoma

Erdheim-Chester disease (ECD) is an infrequent, autoimmune disorder that is not Langerhans histiocytosis and is characterized by bilateral sclerosis of the diametaphyseal medullary regions of the long bones and possible multiorgan involvement. A mononuclear foam histiocyte infiltrate determines the condition's histopathologic form and extensive fibrosis. A case of ECD in a 52-year-old man with retroperitoneal infiltration and bone involvement is described here, in whom the diagnosis was established only after a 3-year course of multiple nonspecific symptoms.

Establishing a diagnosis of ECD is challenging, especially due to vague and nonspecific presenting symptoms. Nonetheless, it is important to recognize both its unique radiographic findings, particularly, symmetric patchy sclerosis of the long bones, and the pathognomonic infiltration of foamy histiocytes with dense fibrosis, as patients can benefit from interferon-alpha therapy if ECD is established.

Erdheim Chester disease in a patient with Burkitt lymphoma: a case report and review of literature

Background

Erdheim Chester disease (ECD) is a rare, non-Langerhans cell histiocytosis characterized by widespread tissue infiltration by CD68-positive, CD1a-negative foamy histiocytes. ECD can be difficult to identify, and diagnosis relies on the presence of histiocytes with certain histologic and immunophenotypic features in an appropriate clinical and radiologic setting. Clinical signs and symptoms are variable depending on which organ systems are involved. Most patients have at least skeletal involvement with bone pain as well as fatigue. Other common manifestations include diabetes insipidus, cardiac, periaortic, or retro-orbital infiltration/fibrosis, kidney impairment, xanthelasmas, among others.

Case presentation

Herein, we describe a case of BRAF-mutation positive ECD in a patient with Burkitt lymphoma, and we review recent literature.

Conclusion

Underlying BRAF and other MAPK pathway mutations are identified in approximately 50% of cases of ECD, which aids in diagnosis as well as enables novel targeted treatments. ECD patients have an increased risk of myeloid neoplasms; however, unlike other histiocytoses, an association with lymphoproliferative disorders has not been recognized.

Effective BRAF inhibitor vemurafenib therapy in a 2-year-old patient with sequentially diagnosed Langerhans cell histiocytosis and Erdheim-Chester disease

Erdheim-Chester disease (ECD) is a rare histiocytic disorder, characterized by the xanthomatous infiltration of tissues by CD68-positive and CD1a-/CD100-negative foamy histiocytes. In childhood, ECD is exceptionally rare, and only a dozen cases have been published so far. The cooccurence of Langerhans cell histiocytosis (LCH) and ECD is even rarer. Here, we report a 2-year-old boy, the youngest patient in the literature so far, who was diagnosed with concomitant BRAF mutation-positive LCH and ECD. In his case, conventional LCH treatment proved to be ineffective, but he is the youngest patient who was successfully treated with the BRAF inhibitor vemurafenib.

[Erdheim-Chester disease (ECD), an inflammatory myeloid neoplasia]

In a compatible clinico-radiological setting, the diagnosis of Erdheim-Chester disease (ECD) involves the analysis of histiocytes in tissue biopsies: they are typically foamy and CD68+ CD1a, whereas in Langerhans cell histiocytosis (LCH) they are CD68+ CD1a+. Overlap forms of histiocytoses are frequent. Technetium bone scintigraphy showing nearly constant tracer uptake by the long bones is highly suggestive of ECD and a 'hairy kidney' appearance on abdominal CT scan is observed in more than half ECD cases. CNS involvement is a strong prognostic factor and an independent predictor of death in cases of ECD. Optimal initial therapy for ECD appears to be administration of IFN-α (and/or pegylated IFN-α) and prolonged treatment significantly improves survival; however, tolerance may be poor. Best alternative therapies are anakinra, mainly effective for mild forms of the disease, infliximab, and sirolimus. Cases of ECD present with strong systemic immune activation, involving IFN-α, IL-1/IL1-RA, IL-6, IL-12, and MCP-1, consistent with the systemic immune Th-1-oriented disturbance associated with the disease. Between 57 and 75 % of ECD patients carry the BRAF^V600E mutation, an activating mutation of the proto-oncogene BRAF. More than 50 cases harboring BRAF mutation and with severe multisystemic and refractory ECD (sometimes associated with LCH) have been treated worldwide with vemurafenib, a BRAF inhibitor that proved to be very beneficial. Other recurrent mutations of the MAPK (NRAS, MAP2K1) and PIK3 pathways (PIK3CA) have been found among ECD patients. As recurrent mutations in the MAPK pathway are found in ECD and LCH on a background of chronic inflammation, we believe that both conditions should be redefined as an inflammatory myeloid neoplasia.

Erdheim-Chester disease

Erdheim-Chester disease (ECD) is rare form of non-Langerhans cells histiocytosis with multiorgan involvement. Individuals are more frequently affected in their fifth decade and there is a slight male prevalence. Recent studies have demonstrated that ECD patients bare mutations in the proto-oncogene BRAF (and more rarely in other genes involved in the MAPK activation pathway), suggesting a critical role of this pathway in the pathogenesis and a possible clonal origin of the disease. Clinical manifestations are extremely protean and virtually every organ system can be affected. The most common clinical features include skeletal involvement with typical bilateral osteosclerotic lesions of long bones of the lower limbs, diabetes insipidus, cardiovascular involvement with circumferential thickening of the aorta ("coated aorta"), and retroperitoneal fibrosis ("hairy kidney"). Cardiovascular and central nervous system (CNS) involvement are associated with the worst prognosis. Biopsy is necessary to establish a definite diagnosis with the identification of CD68+/CD1a-/S100- foamy histiocytes. Currently, interferon-α is the first-line treatment in ECD, as it has been clearly demonstrated to increase overall survival. Anakinra and infliximab have also led to encouraging results and should be taken into consideration when treatment with interferon-α fails. More recently, the BRAF-inhibitor vemurafenib has been used in small groups of ECD patients with optimal efficacy in all treated cases. Nevertheless, its adverse effects and the scanty data on its long-term efficacy and safety still discourage its use as a first-line option. Further studies are still warranted to better understand and treat this neglected and overlooked disease.

Erdheim-Chester disease mimicking an intracranial trigeminal schwannoma: case report

Erdheim-Chester disease (ECD) is non-Langerhans histiocytosis that can affect multiple organ systems. It usually affects middle-aged patients, and only a few reports of ECD in children appear in the literature. Central nervous system involvement is a common feature that usually occurs as infiltration of the hypothalamus-pituitary axis, cerebellum, and/or brainstem. Meningeal involvement occurs less commonly. In this article, the authors discuss a rare pediatric case of ECD presenting as an infiltrative mass of the trigeminal nerve and resembling the clinical and imaging features of a trigeminal schwannoma.

Clinical considerations and key issues in the management of patients with Erdheim-Chester Disease: a seven case series

BACKGROUND

Erdheim-Chester Disease (ECD), a non Langerhans' cell histiocytosis of orphan nature and propensity for multi-systemic presentations, comprises an intricate medical challenge in terms of diagnosis, treatment and complication management.

OBJECTIVES

The objectives are to report the clinical, radiological and pathological characteristics, as well as cardinal therapeutic approaches to ECD patients and to provide clinical analyses of the medical chronicles of these complex patients.

METHODS

Patients with biopsy proven ECD were audited by a multi-disciplinary team of specialists who formed a coherent timeline of all the substantial clinical events in the evolution of their patients' illness.

RESULTS

Seven patients (five men, two women) were recruited to the study. The median age at presentation was 53 years (range: 39 to 62 years). The median follow-up time was 36 months (range: 1 to 72 months). Notable ECD involvement sites included the skeleton (seven), pituitary gland (seven), retroperitoneum (five), central nervous system (four), skin (four), lungs and pleura (four), orbits (three), heart and great vessels (three) and retinae (one). Prominent signs and symptoms were fever (seven), polyuria and polydipsia (six), ataxia and dysarthria (four), bone pain (four), exophthalmos (three), renovascular hypertension (one) and dyspnea (one). The V600E BRAF mutation was verified in three of six patients tested. Interferon-α treatment was beneficial in three of six patients treated. Vemurafenib yielded dramatic neurological improvement in a BRAF mutated patient. Infliximab facilitated pericardial effusion volume reduction. Cladribine improved cerebral blood flow originally compromised by perivenous lesions.

CONCLUSIONS

ECD is a complex, multi-systemic, clonal entity coalescing both neoplastic and inflammatory elements and strongly dependent on impaired RAS/RAF/MEK/ERK signaling.

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

Erdheim-Chester disease (ECD) is a rare, non-Langerhans histiocytosis. Recent findings suggest that ECD is a clonal disorder, marked by recurrent BRAFV600E mutations in >50% of patients, in which chronic uncontrolled inflammation is an important mediator of disease pathogenesis. Although ∼500 to 550 cases have been described in the literature to date, increased physician awareness has driven a dramatic increase in ECD diagnoses over the last decade. ECD frequently involves multiple organ systems and has historically lacked effective therapies. Given the protean clinical manifestations and the lack of a consensus-derived approach for the management of ECD, we provide here the first multidisciplinary consensus guidelines for the clinical management of ECD. These recommendations were outlined at the First International Medical Symposium for ECD, comprised of a comprehensive group of international academicians with expertise in the pathophysiology and therapy of ECD. Detailed recommendations on the initial clinical, laboratory, and radiographic assessment of ECD patients are presented in addition to treatment recommendations based on critical appraisal of the literature and clinical experience. These formalized consensus descriptions will hopefully facilitate ongoing and future research efforts in this disorder.

Erdheim-Chester Disease: a comprehensive review of the literature

Erdheim-Chester Disease (ECD) is a rare form of non Langerhans' cell histiocytosis. Individuals affected by this disease are typically adults between their 5th and 7th decades of life. Males and females are almost equally affected. The multi systemic form of ECD is associated with significant morbidity, which may arise due to histiocytic infiltration of critical organ systems. Among the more common sites of involvement are the skeleton, central nervous system, cardiovascular system, lungs, kidneys (retroperitoneum) and skin. The most common presenting symptom of ECD is bone pain. The etiology of ECD is unknown yet thought to be associated with an intense TH1 immune response. It may also be associated with the V600E BRAF mutation, as described in as many as half of the patients in recent studies. Bilateral symmetric increased tracer uptake on ^99mTc bone scintigraphy affecting the periarticular regions of the long bones is highly suggestive of ECD. However, definite diagnosis of ECD is established only once CD68(+), CD1a(−) histiocytes are identified within a biopsy specimen. At present, this obscure ailment embodies numerous challenges to medical science. Given its rarity, it is diagnostically elusive and requires a high level of clinical suspicion. Therapeutically, it is of limited alternatives. Currently, interferon-α is the most extensively studied agent in the treatment of ECD and serves as the first line of treatment. Treatment with other agents is based on anecdotal case reports and on the basis of biological rationale. Nevertheless, cladribine (2CDA), anakinra and vemurafenib are currently advocated as promising second line treatments for patients whose response to interferon-α is unsatisfactory. Overall, the 5 year survival of ECD is 68%. Herein, the authors mustered and brought about a panoramic consolidation of all the relevant facts regarding ECD. This work highlights the different clinical, radiological and pathological manifestations associated with ECD, the differential diagnoses, the various treatment options and the acknowledged science explaining the disease.

Erdheim-Chester disease with multisystem involvement in a 4-year-old

Erdheim-Chester disease is a rare form of non-Langerhans histiocytosis of unknown origin occurring mainly in adults. It is extremely rare in children. We report a case of a 4-year-old boy with Erdheim-Chester disease that initially presented as hemifacial palsy and bone pain with multisystem involvement. We describe radiographic findings of bones that show characteristic bilateral symmetrical osteosclerosis with atypical osteolytic lesions in addition to CT findings for pulmonary involvement and MR findings for intracranial lesions.

Non-Langerhans cell histiocytosis with isolated CNS involvement: an unusual variant of Erdheim-Chester disease

Benign histiocytic proliferations are identified by their component cells and classified as either Langerhans cell histiocytosis or non-Langerhans cell histiocytosis. We report a 58-year-old Caucasian woman who presented with diabetes insipidus and was found to harbor a large suprasellar mass. Histopathological analysis was consistent with non-LCH. The differential diagnoses included juvenile xanthogranuloma, adult-onset xanthogranuloma, xanthoma disseminatum, Rosai-Dorfman disease, and Erdheim-Chester disease. Immunohistochemical examination demonstrated a proliferation of large lipid-laden histiocytic cells which were positive for CD68, negative for S100 protein, and showed only faint, background staining for CD1a. We present a case of an autopsy-confirmed non-Langerhans cell histiocytosis limited to the central nervous system and evaluated with both immunohistochemical and ultrastructural studies. Based on the multifocality, anatomic distribution, and immunostaining features, a diagnosis of Erdheim-Chester disease was made. This is only the second reported case of Erdheim-Chester disease with intracranial involvement but absence of extracerebral manifestations. Given the overlapping clinicopathologic, radiographic, and immunohistochemical profiles, differentiating between these rare histiocytic disorders can often present a significant diagnostic challenge. A systematic approach using all available clinical, laboratory, radiographic, histologic, immunohistochemical and ultrastructural data is essential for proper discrimination between the numerous histiocytoses.

Chemotherapy and interferon-alpha treatment of Erdheim-Chester disease

Erdheim-Chester disease (ECD) is a rare non-Langerhans cell histiocytosis of an unknown origin. The prognosis of ECD is variable, and it mainly depends on the involved anatomic sites. The treatment modalities have not been standardized. Interferon-alpha (IFN) has been reported to be effective in the management of ECD. We report here on an uncommon case with ECD in a 17-year-old female who had multiple lesions in the whole body and she was treated with chemotherapy and IFN. She has remained disease-free for 2 years after the completion of treatment.