Optimal therapy for adults with Langerhans cell histiocytosis bone lesions. PLoS One. 2012;7:e43257. [PMID: 22916233 PMCID: PMC3419729 DOI: 10.1371/journal.pone.0043257]

Phase 2 study using low dose cytarabine for adult patients with newly diagnosed Langerhans cell histiocytosis

Langerhans cell histiocytosis (LCH) lacks a standardized first-line therapy. This single-center, phase 2 prospective study (NCT04121819) enrolled 61 newly diagnosed adult LCH patients with multisystem or multifocal single system disease from October 2019 to June 2022. Subcutaneous cytarabine (100 mg/m2 for 5 days) was administered in 35-day cycles for 12 total cycles. The primary endpoint was event-free survival (EFS). The median age was 33 years (range 18-66). Twelve patients (19.7%) had liver involvement, of which 2 also had spleen involvement. Among 43 patients undergoing next-generation sequencing, BRAF alterations (44.2%) were most frequent, followed by TP53 (16.3%), MAP2K1 (14.0%) and IDH2 (11.6%). MAPK pathway alterations occurred in 28 patients (65.1%). The overall response rate was 93.4%, with 20 (32.7%) achieving complete response and 37 (60.7%) partial response. After a median 30 months follow-up, 21 (34.4%) relapsed without deaths. Estimated 3-year OS and EFS were 100.0% and 58.5%, respectively. Multivariate analysis identified ≥3 involved organs (P = 0.007; HR 3.937, 95% CI: 1.456-9.804) and baseline lung involvement (P = 0.028; HR 2.976, 95% CI: 1.126-7.874) as poor prognostic factors for EFS. The most common grade 3-4 toxicities were neutropenia (27.9%), thrombocytopenia (1.6%), and nausea (1.6%). In conclusion, cytarabine monotherapy is an effective and safe regimen for newly diagnosed adults, while baseline lung or ≥3 involved organs confers poor prognosis.

Solitary Skull Langerhans Cell Histiocytosis Presenting With a Pus Draining Fistula: An Unusual Presentation and Review of Literature

Langerhans cell histiocytosis (LCH) is a rare condition in adults, especially when it is limited to a single area of the skull, known as solitary calvarial involvement. In this case report, we present a unique instance of LCH affecting the parietal bone with a pus-draining fistula. This is a rare and unusual presentation at this location, which has been scarcely reported in medical literature. A 30-year-old woman with no prior comorbidity presented with complaints of headache that persisted for a year. She also had swelling on her scalp and a yellowish discharge for 3 weeks, but no neurological problems were observed. Radiology revealed thinning of the calvaria, with ragged margins along the inner table, multiple focal erosions, and involvement of overlying soft tissue and bony sequestrum. The patient underwent biparietal craniotomy and excision of the lesion. The histopathology report showed LCH. After 8 months of follow-up, there was no recurrence. The management of solitary calvarial involvement by LCH with masquerading presentation as a scalp infection can be achieved through complete excision of the lesions, resulting in a favorable outcome.

Mutant PIK3CA is a targetable driver alteration in histiocytic neoplasms

Langerhans cell histiocytosis (LCH) is an inflammatory myeloid neoplasm characterized by the accumulation of clonal mononuclear phagocyte system cells expressing CD1a and CD207. In the past decade, molecular profiling of LCH as well as other histiocytic neoplasms demonstrated that these diseases are driven by MAPK activating alterations, with somatic BRAFV600E mutations in >50% of patients with LCH, and clinical inhibition of MAPK signaling has demonstrated remarkable clinical efficacy. At the same time, activating alterations in kinase-encoding genes, such as PIK3CA, ALK, RET, and CSF1R, which can activate mitogenic pathways independent from the MAPK pathway, have been reported in a subset of histiocytic neoplasms with anecdotal evidence of successful targeted treatment of histiocytoses harboring driver alterations in RET, ALK, and CSF1R. However, evidence supporting the biological consequences of expression of PIK3CA mutations in hematopoietic cells has been lacking, and whether targeted inhibition of PI3K is clinically efficacious in histiocytic neoplasms is unknown. Here, we provide evidence that activating mutations in PIK3CA can drive histiocytic neoplasms in vivo using a conditional knockin mouse expressing mutant PIK3CAH1047R in monocyte/dendritic cell progenitors. In parallel, we demonstrate successful treatment of PIK3CA-mutated, multisystemic LCH using alpelisib, an inhibitor of the alpha catalytic subunit of PI3K. Alpelisib demonstrated a tolerable safety profile at a dose of 750 mg per week and clinical and metabolic complete remission in a patient with PIK3CA-mutated LCH. These data demonstrate PIK3CA as a targetable noncanonical driver of LCH and underscore the importance of mutational analysis-based personalized treatment in histiocytic neoplasms.

Adult-onset Langerhans cell histiocytosis of bone: A case series highlighting a rare entity

Langerhans cell histiocytosis (LCH) is a neoplastic disorder derived from LCH precursor cells that can manifest as a single-system disease or a multisystem disorder. While extensively studied in children, LCH has received less attention in adult patients. We aimed to investigate the pathology and clinical course of LCH in adults presenting with a bone lesion. Cases of osseous LCH diagnosed in patients ≥18 in our center were analyzed. Histologic slides were reviewed, and clinical data were collated. Molecular analysis for BRAF mutation was performed in a subset. Twelve osseous LCH cases with classic morphology and CD1a+/S100+ immunophenotype were identified. Tumors occurred in six females and five males with a median age of 34 years (range: 18-77 years) and involved the craniofacial bones (4), pelvis (3), spine (2), appendicular skeleton (2), and rib (1). Radiographically, tumors appeared as ill-defined lytic lesions, often accompanied by cortical erosion and soft tissue extension, with pain being the most common presentation. On staging work-up with available data, two patients had multifocal bone lesions, two had multi-system disease, and four had solitary lesions. Two patients had prior or concurrent neoplasms, and 63 % of patients (5 out of 8) had a history of smoking. BRAF mutational analysis performed in six cases revealed a BRAFV600E mutation in one, negative result in one, and failed in four archived specimens. Our study highlights the importance of performing staging in patients with adult-onset LCH presenting as a bone lesion, as the clinical extent of the disease can vary widely among individuals.

Clinical and prognostic features of Langerhans cell histiocytosis in adults

Langerhans cell histiocytosis (LCH) is a rare disease characterized by clonal expansion of CD1a+ CD207+ myeloid dendritic cells. The features of LCH are mainly described in children and remain poorly defined in adults; therefore, we conducted a nationwide survey to collect clinical data from 148 adult patients with LCH. The median age at diagnosis was 46.5 (range: 20-87) years with male predominance (60.8%). Among the 86 patients with detailed treatment information, 40 (46.5%) had single system LCH, whereas 46 (53.5%) had multisystem LCH. Moreover, 19 patients (22.1%) had an additional malignancy. BRAF V600E in plasma cell-free DNA was associated with a low overall survival (OS) rate and the risk of the pituitary gland and central nervous system involvement. At a median follow-up of 55 months from diagnosis, six patients (7.0%) had died, and the four patients with LCH-related death did not respond to initial chemotherapy. The OS probability at 5 years post-diagnosis was 90.6% (95% confidence interval: 79.8-95.8). Multivariate analysis showed that patients aged ≥60 years at diagnosis had a relatively poor prognosis. The probability of event-free survival at 5 years was 52.1% (95% confidence interval: 36.6-65.5), with 57 patients requiring chemotherapy. In this study, we first revealed the high rate of relapse after chemotherapy and mortality of poor responders in adults as well as children. Therefore, prospective therapeutic studies of adults with LCH using targeted therapies are needed to improve outcomes in adults with LCH.

Cladribine and cytarabine in children refractory high risk multisystem Langerhans cell histiocytosis

There is no uniform regimen for refractory Langerhans cell histiocytosis (LCH). We retrospectively described patients with refractory multisystem and risk organ involvement LCH treated with the low-dose (Ara-c, 100 mg/m2/d × 5day; 2-CDA, 5 mg/m2/d × 5day) chemotherapy (LDC) and the intermediate-dose (Ara-c, 500 mg/m2/d × 5day; 2-CDA, 9 mg/m2/d × 5day) chemotherapy (IDC). 26 patients and 10 patients receiving the LDC and IDC regimen from January 2013 to December 2016 were included in the study. The overall response rate exhibited no significant difference between the LDC and IDC groups after four courses (76.9% vs 90%, P = 0.375) and eight courses (80.8% vs 100%, P = 0.135) of treatment. No statistical differences in the overall survival rate were observed between the two groups, but 5-year event-free survival rate of patients in the IDC group was higher than that in the LDC group at the median follow-up of 6.16 and 5.07 years (88.9% vs 52.9%, P = 0.033). The patients in the IDC group had more severe myelosuppression than those in the LDC group (grade 3/4 myelosuppression, 80% vs 19.2%, P = 0.001). The intermediate-dose regimen of 2CDA and Ara-c had a higher event-free survival rate and a similar overall survival rate compared with the low-dose regimen.

[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.

Treatment of Langerhans cell histiocytosis with subcutaneous cytarabine

Patients with Langerhans cell histiocytosis (LCH) have been effectively treated with intravenous cytarabine. Intravenous or subcutaneous cytarabine infusions have been effective for leukemia patients, and pharmacokinetic studies have shown very similar blood levels of the drug with either route. We present three LCH patients treated with subcutaneous cytarabine either because intravenous access could not be maintained or due to patient refusal. One patient with pulmonary and skin LCH had a complete response. Another patient had a partial response of pulmonary and cutaneous lesions, but progressive bone disease. The third patient was treated for LCH-related cerebellar changes eight years after the diagnosis of isolated diabetes insipidus, with stable brain MRI for 5 years post-treatment. Subcutaneous cytarabine administration provides an alternative for patients with LCH in whom vascular access is not possible or practical, such as in some resource-limited circumstances.

Adult-onset Langerhans cell histiocytosis – A Trojan horse of oral cavity: A case report with rare clinical presentation

Langerhans cell histiocytosis (LCH), earlier recognised as histiocytosis X, is a rare haematological illness involving infants and young children. LCH is caused by unrestrained stimulation and proliferation of usual antigen presenting cells, Langerhans cells (LCs) and the disease demonstrates extensive clinical and radiographic features involving multiple sites. Since the incidence is relatively low limited data is available regarding the epidemiology of LCH, with approximation of 2-5 cases per million populations per year. LCH has male predilection with jaws involved in 10-20% cases and only 1% of the cases affecting maxilla, masquerading as periodontal or periapical pathology. We report a case of 48-year-old female with LCH involving posterior maxilla. This is a unique presentation corresponding to age, gender, location and severity. Dental clinicians should be aware of this and consider it to be a part of their differential diagnosis pertaining to unresolved periodontal pathology as it mimics clinically and radiographically.

Langerhans cell histiocytosis involving only the thymus in an adult: A case report

BACKGROUND

Langerhans cell histiocytosis (LCH) is a rare disease of unknown etiology. LCH involving the thymus is mainly seen in pediatric patients and is extremely rare in adults. In this report, we describe a rare case of LCH originating from the thymus in an adult.

CASE SUMMARY

A 56-year-old man was admitted in April 2022 with complaints of intermittent dizziness since 2020, which had worsened in the previous 10 d. The physical chest examination was negative, and there was a history of hypertension for > 2 years. Chest computed tomography showed a nodular soft tissue density shadow in the anterior mediastinum measuring approximately 13 mm × 9 mm × 8 mm. Postoperative pathological findings confirmed the diagnosis of LCH.

CONCLUSION

It is challenging to differentiate LCH involving the thymus from thymoma in imaging features. Pathological biopsy remains the gold standard when an anterior mediastinal occupying lesion is found.

Langerhans cell histiocytosis in adults: literature review

Langerhans cells histiocytosis is a variant of malignant histiocytosis. The course and symptoms vary. patients with localized forms have a better prognosis, because local therapy is effective. patients with multifocal forms of histiocytosis receive systemic drug therapy, which cures some of the patients. This review provides up-to-date data about typical presentation of the organ involvement, diagnosis, course and therapy of various forms of Langerhans cells histiocytosis.

Langerhans cell histiocytosis in adolescent patients: a single-centre retrospective study

Background

Langerhans cell histiocytosis (LCH) is a myeloid dendritic cell disorder frequently affecting children more than adults. The presentation of LCH varies with age, however, the clinical characteristics and genetic profiles of adolescent LCH remain elusive. To address the knowledge gap, we performed a single-centre retrospective study of 36 adolescent LCH patients aged between 14 and 17 years at Peking Union Medical College Hospital.

Results

At the time of diagnosis, 10 patients were classified as unifocal single system LCH (27.8%), 2 patients had pulmonary single system LCH (5.6%), 5 patients had multifocal single system LCH with bone involvement (13.9%), and 19 patients had multisystem LCH (52.8%). The most prevalent involvement in multisystem patients was the pituitary gland (78.9%), followed by the bone (42.1%), lung (42.1%), and lymph nodes (42.1%). Eight (42.1%) patients had risk organ involvement. BRAF^N486_P490 was detected in 50% of patients who underwent next generation sequencing, and BRAF^V600E was detected in one patient. Chemotherapies were the first line treatment in 24 patients. One patient died and thirteen patients relapsed during the follow-up. The estimated 5-year OS rate and EFS rate were 94.7% and 59.0%, respectively.

Conclusions

In this study, we report a large series of adolescent LCH patients. The clinical characteristics of adolescent LCH patients may be close to adult LCH. Compared with pediatric cases, adolescent LCH tends to have more pituitary lesions and pulmonary involvement, fewer skin and hematopoietic involvement, a higher frequency of BRAF deletion mutation, and a lower frequency of BRAF^V600E mutation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13023-022-02436-0.

International expert consensus recommendations for the diagnosis and treatment of Langerhans cell histiocytosis in adults

Langerhans cell histiocytosis (LCH) can affect children and adults with a wide variety of clinical manifestations, including unifocal, single-system multifocal, single-system pulmonary (smoking-associated), or multisystem disease. The existing paradigms in the management of LCH in adults are mostly derived from the pediatric literature. Over the last decade, the discovery of clonality and MAPK-ERK pathway mutations in most cases led to the recognition of LCH as a hematopoietic neoplasm, opening the doors for treatment with targeted therapies. These advances have necessitated an update of the existing recommendations for the diagnosis and treatment of LCH in adults. This document presents consensus recommendations that resulted from the discussions at the annual Histiocyte Society meeting in 2019, encompassing clinical features, classification, diagnostic criteria, treatment algorithm, and response assessment for adults with LCH. The recommendations favor the use of 18F-Fluorodeoxyglucose positron emission tomography-based imaging for staging and response assessment in the majority of cases. Most adults with unifocal disease may be cured by local therapies, while the first-line treatment for single-system pulmonary LCH remains smoking cessation. Among patients not amenable or unresponsive to these treatments and/or have multifocal and multisystem disease, systemic treatments are recommended. Preferred systemic treatments in adults with LCH include cladribine or cytarabine, with the emerging role of targeted (BRAF and MEK inhibitor) therapies. Despite documented responses to treatments, many patients struggle with a high symptom burden from pain, fatigue, and mood disorders that should be acknowledged and managed appropriately.

Adult Langerhans Cell Histiocytosis and the Skeleton

Langerhans cell histiocytosis (LCH) is a rare inflammatory neoplasia in which somatic mutations in components of the MAPK/ERK pathway have been identified. Osseous involvement is evident in approximately 80% of all patients and may present as a single osteolytic lesion, as a multi-ostotic single system disease or as part of multisystem disease. Both exogenous, such as treatment with glucocorticoids, and endogenous parameters, such as anterior pituitary hormone deficiencies and inflammatory cytokines, may severely affect bone metabolism in LCH. Computed tomography (CT) or magnetic resonance imaging (MRI) are usually required to precisely assess the degree of bone involvement; 18F-fluorodeoxyglucose (FDG) positron emission tomography-CT can both detect otherwise undetectable LCH lesions and differentiate metabolically active from inactive or resolved disease, while concomitantly being useful in the assessment of treatment response. Treatment of skeletal involvement may vary depending on location, extent, size, and symptoms of the disease from close observation and follow-up in unifocal single-system disease to chemotherapy and gene-targeted treatment in cases with multisystem involvement. In any case of osseous involvement, bisphosphonates might be considered as a treatment option especially if pain relief is urgently needed. Finally, a patient-specific approach is suggested to avoid unnecessary extensive surgical interventions and/or medical overtreatment.

Neutralizing Anti-IL-17A Antibody Demonstrates Preclinical Activity Enhanced by Vinblastine in Langerhans Cell Histiocytosis

Langerhans cell histiocytosis (LCH) is an inflammatory myeloid neoplasm characterised by the accumulation into granulomas of apoptosis-resistant pathological dendritic cells (LCH-DCs). LCH outcome ranges from self-resolving to fatal. Having previously shown that, (i) monocyte-derived DCs (Mo-DCs) from LCH patients differentiate into abnormal and pro-inflammatory IL-17A-producing DCs, and (ii) recombinant IL-17A induces survival and chemoresistance of healthy Mo-DCs, we investigated the link between IL-17A and resistance to apoptosis of LCH-DCs. In LCH granulomas, we uncovered the strong expression of BCL2A1 (alias BFL1), an anti-apoptotic BCL2 family member. In vitro, intracellular IL-17A expression was correlated with BCL2A1 expression and survival of Mo-DCs from LCH patients. Based on the chemotherapeutic drugs routinely used as first or second line LCH therapy, we treated these cells with vinblastine, or cytarabine and cladribine. Our preclinical results indicate that high doses of these drugs decreased the expression of Mcl-1, the main anti-apoptotic BCL2 family member for myeloid cells, and killed Mo-DCs from LCH patients ex vivo, without affecting BCL2A1 expression. Conversely, neutralizing anti-IL-17A antibodies decreased BCL2A1 expression, the downregulation of which lowered the survival rate of Mo-DCs from LCH patients. Interestingly, the in vitro combination of low-dose vinblastine with neutralizing anti-IL-17A antibodies killed Mo-DCs from LCH patients. In conclusion, we show that BCL2A1 expression induced by IL-17A links the inflammatory environment to the unusual pro-survival gene activation in LCH-DCs. Finally, these preclinical data support that targeting both Mcl-1 and BCL2A1 with low-dose vinblastine and anti-IL-17A biotherapy may represent a synergistic combination for managing recurrent or severe forms of LCH.

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.

Clinical features and treatment of Langerhans cell histiocytosis

Langerhans cell histiocytosis (LCH) is caused by the expansion of CD1a+/CD207+ cells and is characterised by a wide spectrum of organ involvement and dysfunction, affecting all ages. While almost all organs and systems can be affected, only the involvement and dysfunction of liver, spleen, and haematopoietic system influence survival. The LCH pathogenic cells are defined by universal activation of the mitogen-activated protein kinase (MAPK) signalling pathway. The most common alteration is a somatic BRAFV600E mutation, which is present in approximately two-thirds of the cases, followed by MAP2K1 mutations. Treatment of LCH is risk-adapted; patients with single lesions may respond well to local treatment, whereas patients with multi-system disease require systemic chemotherapy. While survival for patients without organ dysfunction is excellent, mortality rates for patients with organ dysfunction may reach 20%. Despite progress made in the treatment of LCH, disease reactivation rates remain above 30%, and standard second-line treatment has yet to be established. Long-term effects, including neuroendocrine dysfunction and neurodegeneration, represent a major challenge for survivors. Treatment with BRAF or MEK inhibitors results in immediate responses, but reactivations are very common after discontinuation. Their role as single agents and in combination with chemotherapy is being explored.

Langerhans cell histiocytosis in adults: a retrospective, single-center case series

Langerhans cell histiocytosis is rare in adults, and most of what we know about its diagnosis and treatment comes from pediatric studies. We report clinical findings and results of treatment in a retrospective series of 63 consecutive adult patients (18-76 years old), treated at our pediatric unit from 1990 to 2020 using the same approach as for children. Patients were classified as having single-system disease (SS-LCH) in 41 cases, which was unifocal in 34 of them and multifocal in 7, or multisystem disease (MS-LCH) in 17 and primary pulmonary (pLCH) in 5. Twenty patients also had diabetes insipidus. A "wait and see" strategy was recommended after biopsy/surgery for patients with unifocal SS-LCH. Systemic treatment was proposed for cases of SS-LCH involving "special sites" or with multifocal disease, and in cases of MS-LCH. EFS and OS for the cohort as a whole were 62.2% and 100%, respectively, at 5 years and 52.5% and 97.6% at 10 years. Three patients died due to the damage caused by the multiple therapies administered. The rate of disease reactivation was high (affecting 40% of cases), with several reactivations over the years despite multiple lines of treatment. Though clinical history of LCH may differ between adults and children, in the absence of specific, tailored protocols, clinical approach to adult cases may draw on pediatric experience. Patients with limited disease have a good prognosis without any need for systemic therapy. Potentially greater toxicity in adults of systemic treatments generally used in pediatric setting should be borne in mind.

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.

Isolated Bone Lesions in the Mandible and Maxilla of Langerhans Cell Histiocytosis Treated with Fractionated Stereotactic Low-Dose Radiotherapy: Case Report and 5-Year Follow-Up

Langerhans cell histiocytosis is a benign histiocytic disorder touching both genders and can occur at any age. It is currently classified by the Histiocyte Society as an inflammatory myeloid neoplasm of mixed cellularity. Clinically, it is illustrated by single or multiple osteolytic bone lesions associated with ulceration of the skin and soft tissues. Disease outcome is highly variable, depending on the degree of involvement. Bone pathologies are observed in 60% of cases as uni- or multifocal lesions. Several treatment modalities have been proposed and include surgical excision, intralesion steroid injection, chemotherapy, and low-dose radiotherapy. In this paper, we report a case of a 42-year-old male suffering from gingival swelling in the left side of his mandible and the right side of the maxilla. Clinical, radiological, and histological examinations confirm the diagnosis of Langerhans cell histiocytosis. Hematological investigation, entire body CT scan, and bone scintigraphy confirmed the limitation of the lesions in the right maxilla and on the left mandible. The lesions were treated with fractionated stereotactic low-dose radiotherapy, 24 Gy in 16 fractions, by using a linear accelerator with a custom-made rigid mask for accurate immobilization of the head with confirmed precision, which allows noninvasive approaches. Complete remission was achieved clinically and radiologically after one year, and a panoramic X-ray after 5 years confirms the bone healing process. Fractionated stereotactic low-dose RT could be adopted as an effective treatment.

Multifocal Langerhans cell histiocytosis in a child

Langerhans Cell Histiocytosis (LCH) is a rare disorder sometimes called the disorder of the “monocyte-macrophage system”. This condition is characterized by the proliferation of abnormal Langerhans cells within different tissues. Skin rash is the typical early feature, but bony involvement is the second most common presentation. The most common complications are musculoskeletal disabilities, hearing problems, skin scarring, neuropsychiatric defects and most importantly, progression to secondary malignancies like leukemia. Early recognition and treatment can reduce morbidity and mortality. Herein, we report a case of a 10-year-old male presenting with a tender, palpable mass in the lower limb. On initial imaging, a lesion involving the diaphysis of the fibula was observed, raising concerns of Ewing sarcoma. Biopsy was planned along with whole-body MRI, revealing multifocal single system Langerhans cell histiocytosis. Given the rarity of fibular involvement in LCH, distinguishing between LCH and common malignancies within this age-group can be challenging. Through this case report, we hope to emphasize the importance of considering LCH in the differential diagnosis to ensure a timely diagnosis, fitting treatment and improvement in prognosis of the condition.

Update on Pulmonary Langerhans Cell Histiocytosis

Pulmonary Langerhans cell (LC) histiocytosis (PLCH) has unknown cause and is a rare neoplastic disorder characterized by the infiltration of lungs and various organs by bone marrow-derived Langerhans cells with an accompanying strong inflammatory response. These cells carry somatic mutations of BRAF gene and/or NRAS, KRAS, and MAP2K1 genes, which cause activation of the mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) signaling pathway. PLCH occurs predominantly in young smokers, without gender predominance. Lungs might be involved as an isolated organ or as part of a multiorgan disease. High-resolution computed chest tomography plays an outstanding role in PLCH diagnosis. The typical radiological picture of PLCH is the presence of small intralobular nodules, “tree in bud” opacities, cavitated nodules, and thin- and thick-walled cysts, frequently confluent. Histological examination of the lesion and demonstration of characteristic eosinophilic granulomas with the presence of LCs that display antigen CD1a or CD207 in immunohistochemistry are required for definite diagnosis. Smoking cessation is the most important recommendation for PLCH patients, but treatment of progressive PLCH and multisystem disease is based on chemotherapy. Recently, new targeted therapies have been implemented.

Langerhans cell histiocytosis: A rare cause of pathological rib fracture

Langerhans cell histiocytosis, formerly known as histiocytosis X, represents clonal proliferations of the antigen-presenting dendritic cells, which are normally found in many organs. It is a rare disease which tends to affect children and adolescents. In particular, adult-onset type is very rare. Herein, we present a female adult diagnosed with Langerhans cell histiocytosis of the rib without any systemic involvement which was successfully treated with surgery.

A Case of Burnt-Out Langerhans Cell Histiocytosis Presenting as Postpartum Hypopituitarism

Objective

To evaluate the case of a woman who presented with central hypogonadism and diabetes insipidus and further developed a persistent cough leading to an unexpected diagnosis of burnt-out Langerhans cell histiocytosis (LCH).

Methods

Clinical and laboratory endocrine evaluation, magnetic resonance imaging, high-resolution computed tomography, and open-lung biopsy results are discussed.

Results

A 28-year-old woman presented at 10 months postpartum with polydipsia, polyuria, and amenorrhea for 3 months. Her results showed a prolactin level of 25 μg/L (reference,<23.5 μg/L), estrogen level of 91 pmol/L (reference, 110-180 pmol/L), follicle-stimulating hormone level of 6 IU/L (reference, 2-20 IU/L), and luteinizing hormone level of 6 IU/L (reference, 2-70 IU/L). A water-deprivation test found a sodium concentration of 148 mmol/L (reference, 135-145 mmol/L), serum osmolality of 310 mmol/kg (reference, 275-295 mmol/kg), and urine osmolality of 107 mmol/kg (reference, 50-1450 mmol/kg) that improved to 142 mEq/L, 295 mmol/kg, and 535 mmol/kg, respectively, after desmopressin administration. Gadolinium-enhanced pituitary magnetic resonance imaging demonstrated a markedly thickened stalk with uniform enhancement. Chest high-resolution computed tomography confirmed bilateral upper-zone cystic lung disease suggestive of either pulmonary lymphangioleiomyomatosis or LCH. Eventual histology showed CD1a-positive burnt-out LCH. This differentiation was crucial as pulmonary lymphangioleiomyomatosis exacerbates with estrogen therapy and pregnancy, which the patient was able to successfully pursue without disease exacerbation.

Conclusion

The patient's initial presentation was considered as lymphocytic hypophysitis, but subsequent cystic changes on high-resolution computed tomography led to a unifying definitive diagnosis of burnt-out LCH. This case highlights the importance of investigating for uncommon secondary causes of hypophysitis.

Histiocytic disorders: insights into novel biology and implications for therapy of Langerhans cell histiocytosis and Erdheim-Chester disease

Langerhans cell histiocytosis (LCH) and Erdheim-Chester disease (ECD) are caused by mutations of the MAPK pathway, most often BRAFV600E, in myeloid dendritic cells that lead to some overlapping and other unique presentations of the two diseases. LCH occurs in both children and adults, but ECD is primarily found in the latter. The challenges in diagnosing these conditions relates to the rarity of the conditions and that they mimic diseases that are more widely understood, such as certain rashes; bone, lung, and renal diseases; and other malignancies. The histopathology of LCH is definitive, but not so for ECD. Treatment with BRAF and MEK inhibitors has become one of the important advances in the care of these patients.

Langerhans cell histiocytosis

Langerhans cell histiocytosis (LCH) is caused by clonal expansion of myeloid precursors that differentiate into CD1a+/CD207+ cells in lesions that leads to a spectrum of organ involvement and dysfunction. The pathogenic cells are defined by constitutive activation of the MAPK signaling pathway. Treatment of LCH is risk-adapted: patients with single lesions may respond well to local treatment, whereas patients with multisystem disease require systemic therapy. Although survival rates for patients without organ dysfunction is excellent, mortality rates for patients with organ dysfunction may reach 20%. Despite progress made in the treatment of LCH, disease reactivation rates remain above 30%, and standard second-line treatment is yet to be established. Treatment failure is associated with increased risks for death and long-term morbidity, including LCH-associated neurodegeneration. Early case series report promising clinical responses in patients with relapsed and refractory LCH treated with BRAF or MEK inhibitors, although potential for this strategy to achieve cure remains uncertain.

Adult pulmonary Langerhans cell histiocytosis revealed by central diabetes insipidus: A case report and literature review

Langerhans cell histiocytosis (LCH) is a rare systemic and heterogeneous disease secondary to proliferation and diffuse infiltration of immature CD1a-positive dendritic cells, also known as Langerhans cells. LCH affects predominantly paediatric patients and is rarely diagnosed in adulthood. Despite its worldwide prevalence, most reported cases are found in the Japanese population. There is no consensus regarding treatment strategy due to the low incidence of this disease and the diversity of symptoms that appear. An integrative literature review was conducted based on the PubMed database using MeSH terms 'Langerhans', 'histiocytosis' and 'adult'. The present report describes a case of a successfully treated LCH-induced central diabetes insipidus (uncommon presentation in adult patients) as well as an updated review of current evidence published on this matter.

Adult Langerhans cell histiocytosis presenting with multisystem involvement and sarcomatoid features: a case report

Background

Langerhans cell tumors are rare clonal disorders characterized by neoplastic proliferation of dendritic cells that can be further classified into the subtypes Langerhans cell histiocytosis and Langerhans cell sarcoma, which are rare neoplasms exhibiting aggressive features and a poor prognosis. In addition to illustrating the refractoriness and poor outcomes of multisystem Langerhans cell histiocytosis in adults, specific events in this case highlight important characteristics of disease biology that warrant detailed discussion and exposition to a wider audience.

Case presentation

We describe the case of a 42-year-old Caucasian man with Langerhans cell histiocytosis diagnosed from a lesion on the left arm that presented with constitutional symptoms, early satiety, and weight loss. Esophagogastroduodenoscopy showed extensive esophageal and duodenal involvement by Langerhans cell histiocytosis with features of Langerhans cell sarcoma. He was initially treated for Langerhans cell histiocytosis with low doses of cytarabine until he eventually presented clear transformation to acute monoblastic leukemia with complex karyotype that could not be properly controlled, leading eventually to death.

Conclusions

Langerhans cell histiocytosis remains an exceedingly rare entity in adults, frequently presenting as multisystem disease with risk organ involvement. Langerhans cell sarcoma represents an aggressive subtype with extremely poor prognosis for which intensive acute myeloid leukemia induction should be strongly considered.

A Case of Langerhans Cell Histiocytosis With Multifocal, Single-System GI Tract Involvement and Literature Review

Langerhans cell histiocytosis (LCH) is the most common histiocytic disorder, characterized by the pathologic clonal proliferation and accumulation of immature Langerhans cells within organs. Multiple organ systems can be affected, resulting in a spectrum of clinical manifestations. Isolated gastrointestinal involvement in LCH is rare and usually presents in childhood as a multisystem disease and usually has poor outcomes. We describe a 20-year-old Hispanic female with multifocal, single-system gastrointestinal LCH. Initially diagnosed from a CD1a, S100, and CD207 (Langerin) positive appendix tissue after an appendectomy and confirmed multifocal with an endoscopy. She had a full clinical and endoscopic resolution of disease with cytarabine therapy.

Clinical features and outcomes of adult Langerhans cell histiocytosis: a single-center experience

Langerhans cell histiocytosis (LCH) is a clonally expanding neoplasm characterized by the accumulation of CD1a + CD207 + myeloid dendritic cells. As LCH is a rare disease and is presumed to mainly affect children, the clinical features and treatment outcomes of adult LCH have been poorly documented. We retrospectively reviewed 53 adult patients with LCH who were referred to the Institute of Medical Science, the University of Tokyo from 2005 to 2018. The median age at diagnosis was 42 years with a slight female predominance (57%). The time between onset and diagnosis varied among patients (median, 8 months; range, 0-144 months). In total, 40% of the patients had single organ involvement and 60% had multiple organ involvement. Overall, the most frequently affected organ was bone (62%), followed by the central nervous system (34%), and the lung (28%). Twenty-six patients required systemic treatment, and 25 patients underwent the Special C regimen. Twenty patients (80%) who underwent Special C regimen showed a partial response or better with favorable toxicity. All but one patient is still alive. Median progression-free survival has not been reached despite a median follow-up of 35.5 months. Immunohistochemistry revealed that 39% of patients were positive for BRAF-V600E, which was a lower proportion than in previous reports from North America and Europe.

The combination of methotrexate and cytosine arabinoside in newly diagnosed adult Langerhans cell histiocytosis: a prospective phase II interventional clinical trial

BACKGROUND

Langerhans Cell Histiocytosis (LCH) is a rare disease puzzling both children and adults, however outcome of adult patients is unfavorable. This prospective interventional trial aims to test the efficacy and safety of the combination of methotrexate and cytosine arabinoside in adult LCH patients.

METHOD

A total of 36 patients enrolled diagnosed with LCH and treated in our center from 1st Jan, 2014 to 30th Jun, 2016.

RESULT

Nineteen patients underwent the detection of BRAF mutation, with a positive rate of 21.1%. The overall response rate was 100%, only 16.7% achieved complete response. The overall regression rate of osseous lesions was 100%. Regression of central nervous system involvement was also favorable. After a median follow-up of 44 months, the estimated event-free survival was 48.9 months, the overall survival rate was 97.2%. The risk organ involvement showed strong prognostic value, EFS was 34.1 or 54.6 months (p = 0.001) in groups with/without risk organ involvement respectively. Neutropenia and thrombocytopenia were the most common adverse effects.

CONCLUSION

The regimen of methotrexate and cytosine arabinoside (MA) is effective and safe in treating adult LCH patients, and timely preventions may be considered for the high incidence of hematological adverse effects.

TRIAL REGISTRATION

Trial No. NCT02389400 on Clinicaltrials.gov, registered on 10th Mar. 2015.

Long-term efficacy and safety of 2CdA (cladribine) in extra-pulmonary adult-onset Langerhans cell histiocytosis: analysis of 23 cases from the French Histiocytosis Group and systematic literature review

Langerhans cell histiocytosis (LCH) is a rare protean disease that usually affects children. Few data are available for management of adult-onset cases. A complete picture of the efficacy and safety of 2CdA (2-chlorodeoxyadenosine, cladribine) is lacking. We report a retrospective multicentre study of 23 adult LCH (a-LCH) patients who received single-agent 2CdA and a systematic literature review. All had previously received systemic therapy (vinblastine, n = 19). Response to 2CdA was evaluable in 22 cases. Overall response rate (ORR) was 91%. Complete response (CR) occurred in 11 cases (50%). Nine patients (39%) developed grade 3-4 neutropenia and/or severe infection. A literature review yielded 48 additional cases. A pooled analysis confirmed our findings (ORR: 88%, CR: 49%). CRs were rare with cumulative dose <50 mg/m² . Disease progression rates were 20% and 30% at two and five years, respectively. Partial response (PR) to 2CdA was predictive of disease progression. Among eight re-treated patients, five went into CR, two in PR, and one died. Single-agent 2CdA is effective in reactivated a-LCH, including at intermediate doses. Toxicity, significant but acceptable, warrants infectious prophylaxis. Complete responders may enter prolonged remission. Further studies are needed to determine 2CdA sequencing with other agents (vinblastine, cytarabine).

Adult Langerhans cell histiocytosis and immunomodulatory drugs: Review and analysis of thirty-four case reports

Langerhans cell histiocytosis (LCH) is a rare neoplastic disease in dendritic cells. LCH is classified as either a single-system (SS) or multisystem (MS) disease. There is not a standard first-line treatment for LCH in adults. We analyzed the efficacy and safety of immunomodulatory drugs (IMiDs) by searching PubMed/MEDLINE for case reports previously published. The clinical response (nonactive disease or active disease that regressed) was 94% in SS and 53% in MS. IMiDs should only be considered for adults with cutaneous SS involvement; in MS, they should be used only for patients not eligible for more aggressive treatments.

Langerhans cell histiocytosis of a metatarsal bone in an adult female

Langerhans cell histiocytosis (LCH) commonly occurs in children. It mimics infection and many benign and malignant tumours. This disease mainly involves the spine, skull and long bones, and its incidence is sporadic in the small bones of the foot and hand. We could not find any case reports with the involvement of a metatarsal bone, and hence, awareness about its possibility is essential to suspect it as a differential diagnosis of lytic lesions in the foot bones and therefore treat it judiciously. We have reported a case of a 35-year-old woman with spontaneous onset of pain over her right foot for the last year. An extensive curettage was performed, where the histology confirmed the features of LCH. Awareness about this entity and its differential diagnosis may help to clinch and early diagnosis and to treat effectively.

Langerhans cell histiocytosis in adults: Advances in pathophysiology and treatment

Langerhans cell histiocytosis (LCH) is a rare systemic disorder characterized by the accumulation of CD1a+/Langerin+ LCH cells and wide-ranging organ involvement. Langerhans cell histiocytosis was formerly referred to as histiocytosis X, until it was renamed in 1987. Langerhans cell histiocytosis β was named for its morphological similarity to skin Langerhans cells. Studies have shown that LCH cells originate from myeloid dendritic cells rather than skin Langerhans cells. There has been significant debate regarding whether LCH should be defined as an immune disorder or a neoplasm. A breakthrough in understanding the pathogenesis of LCH occurred in 2010 when a gain-of-function mutation in BRAF (V600E) was identified in more than half of LCH patient samples. Studies have since reported that 100% of LCH cases show ERK phosphorylation, indicating that LCH is likely to be a clonally expanding myeloid neoplasm. Langerhans cell histiocytosis is now defined as an inflammatory myeloid neoplasm in the revised 2016 Histiocyte Society classification. Randomized trials and novel approaches have led to improved outcomes for pediatric patients, but no well-defined treatments for adult patients have been developed to date. Although LCH is not fatal in all cases, delayed diagnosis or treatment can result in serious impairment of organ function and decreased quality of life. This study summarizes recent advances in the pathophysiology and treatment of adult LCH, to raise awareness of this "orphan disease".

Bone metabolism in Langerhans cell histiocytosis

Langerhans cell histiocytosis (LCH) is a rare disease of not well-defined etiology that involves immune cell activation and frequently affects the skeleton. Bone involvement in LCH usually presents in the form of osteolytic lesions along with low bone mineral density. Various molecules involved in bone metabolism are implicated in the pathogenesis of LCH or may be affected during the course of the disease, including interleukins (ILs), tumor necrosis factor α, receptor activator of NF-κB (RANK) and its soluble ligand RANKL, osteoprotegerin (OPG), periostin and sclerostin. Among them IL-17A, periostin and RANKL have been proposed as potential serum biomarkers for LCH, particularly as the interaction between RANK, RANKL and OPG not only regulates bone homeostasis through its effects on the osteoclasts but also affects the activation and survival of immune cells. Significant changes in circulating and lesional RANKL levels have been observed in LCH patients irrespective of bone involvement. Standard LCH management includes local or systematic administration of corticosteroids and chemotherapy. Given the implication of RANK, RANKL and OPG in the pathogenesis of the disease and the osteolytic nature of bone lesions, agents aiming at inhibiting the RANKL pathway and/or osteoclastic activation, such as bisphosphonates and denosumab, may have a role in the therapeutic approach of LCH although further clinical investigation is warranted.

Langerhans cell histiocytosis at L5 vertebra treated with en bloc vertebral resection: a case report

BACKGROUND

Langerhans cell histiocytosis (LCH) in adult lumbar spine is extremely rare, and optimal treatments remain unclear. In literature, only a few cases of lumbar spine LCH were treated using surgery but en bloc vertebral resection has not been used.

CASE PRESENTATION

A 50-year-old man presented with unbearable radiating pain at his right leg. Radiological studies revealed a solitary osteolytic lesion, which was moderately enhanced on contrast MR imaging and hyper-metabolic on PET/CT, at the right L5 vertebral body and arch. In biopsy, Langerhans cells were observed, but findings were insufficient to establish a diagnosis of LCH. A modified L5 en bloc vertebral resection via anterior and posterior approaches was performed to remove the right 2/3 portion of the L5 vertebra. The left 1/3 vertebral body and left pedicle of L5, which were not affected, were kept in situ to allow short instrumentation and reconstruction. His leg pain disappeared after the surgery, and a precise diagnosis of LCH was established after a throughout histological study of the removed vertebra. The patient further accepted 1 cycle of low-dose radiotherapy postoperatively. At 18-month follow-up, the lumbosacral spine was fused and no local reoccurrence was noticed.

CONCLUSIONS

For lumbar spine LCH, surgery should be considered if there are neurological symptoms or histological diagnosis is indefinite in biopsy. En bloc vertebral resection can be used to alleviate neurological symptoms and prevent local reoccurrence.

Imaging of Benign Tumors of the Osseous Spine

The purpose of this paper is to present an overview of the imaging features of the most prevalent benign bone tumors involving the spine. Benign tumors of the osseous spine account approximately for 1% of all primary skeletal tumors. Many lesions exhibit characteristic radiologic features. In addition to age and location of the lesion, radiographs are an essential step in the initial detection and characterization but are limited to complex anatomy and superposition. CT and MR imaging are often mandatory for further characterization, assessment of local extension and guiding biopsy.

Vinblastine chemotherapy in adult patients with langerhans cell histiocytosis: a multicenter retrospective study

Background

Vinblastine is the standard treatment for children with Langerhans cell histiocytosis (LCH). Whether this treatment could be extended to adults with LCH is questionable. This retrospective multicenter study included 35 adult patients (median age 33 years; 23 men; 80% with multisystem LCH) who were treated with vinblastine + steroids as a first-line chemotherapy and followed for a median time of 83 months. The objectives were to determine the overall response rate (based on the Histiocyte Society criteria), disease reactivation rate, toxicity, permanent consequences, and survival rate corresponding to this treatment. The lung involvement outcome was based on serial lung function tests. The distribution of right-censored end points was estimated by the Kaplan-Meier method. Univariate Cox model with time-fixed and time-varying covariates was used for the predictive analysis of reactivation in the responders. Univariate analyses of risk factors for neurotoxicity were based on nonparametric Wilcoxon rank sum tests and exact Fisher tests.

Results

The median duration of the first course of vinblastine was 7.6 months, with a median cumulative dose of 160 mg [IQR 120–212]. Seventy percent of the patients were responders at the end of this treatment. Subsequently, LCH reactivation occurred with a 5-year cumulative incidence of 40%. During the study, 27 reactivations were observed in 17 patients, and half of these episodes were retreated with vinblastine. At the end of the last vinblastine treatment, 70% of the patients were responders. None of the patients with impaired lung function improved. No grade 3–4 peripheral neuropathy was observed. At the final vinblastine treatment, permanent LCH consequences, primarily pituitary stalk involvement, were present in 15 (43%) patients, and all were present at the time of vinblastine initiation. The 10-year survival rate was 86.2% (95CI, 71.8–100%), and the 2 patients who died from LCH had risk organ localizations.

Conclusions

Vinblastine is an effective and well-tolerated first-line treatment for adult LCH except in patients with lung involvement and impaired lung function. However, a significant portion of patients experienced LCH reactivation during long-term follow up. As in childhood LCH, the presence of risk organ involvement has a negative impact on patient prognosis.

A phase IIa study of afuresertib, an oral pan-AKT inhibitor, in patients with Langerhans cell histiocytosis

BACKGROUND

Langerhans cell histiocytosis (LCH) is a clonal neoplasm characterized by widely varied clinical presentations, including multisystem involvement and systemic inflammatory symptoms. The AKT pathway is relevant to survival and proliferation of dendritic cells, and is also often upregulated in hematopoietic malignancies. A clinical response in an adult patient with LCH participating in the first-in-human trial of afuresertib prompted this prospective trial.

PROCEDURE

The population in the current study included treatment-naïve (n = 7) and recurrent/refractory patients with LCH (n = 10), who received oral afuresertib (125 mg). The majority of patients were treated for > 24 weeks, with four patients receiving treatment for > 48 weeks.

RESULTS

Pharmacokinetic analysis showed similar exposures in previously reported patients with other hematologic malignancies. Primary drug-related toxicities included Grade 1/2 nausea, diarrhea, dyspepsia, and vomiting. Grade 3 toxicities included fatigue, diarrhea, and pain (one of each). Another severe adverse event involved soft tissue necrosis. The overall response rate in evaluable subjects was 33% in treatment-naïve patients and 28% in patients with recurrent/refractory disease, which did not meet the predefined Bayesian criteria for efficacy.

CONCLUSION

Afuresertib has clinical activity in some patients with newly diagnosed and advanced LCH.