Project description:Children with Langerhnans cell histiocytosis (LCH) develop granulomatous lesions with characteristic clonal CD207+ dendritic cells that can arise as single lesions or life-threatening disseminated disease. Despite the wide range of clinical presentations, LCH lesions are histologically indistinguishable based on severity of disease, and uncertain classification as an immune versus neoplastic disorder has historically challenged the development of optimal clinical strategies for patients with LCH. Recently, activating somatic mutations in MAPK pathway genes, most notably BRAFV600E, have been discovered in almost all cases of LCH. Further, the stage of myeloid differentiation in which the mutation arises defines the extent of disease and risk of developing LCH-associated neurodegeneration. MAPK activation in LCH precursor cells drives myeloid differentiation, inhibits migration, and inhibits apoptosis, resulting in accumulation of resilient pathologic dendritic cells that recruit and activate T cells. Recurrent somatic mutations in MAPK pathway genes have also been identified in related histiocytic disorders: juvenile xanthogranuloma, Erdheim-Chester disease, and Rosai-Dorfman disease. New insights into pathogenesis support reclassification of these conditions as a myeloid neoplastic disorders. Continued research will uncover opportunities to identify novel targets and inform personalized therapeutic strategies based on cell of origin, somatic mutation, inherited risk factors, and residual disease.
Project description: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.
Project description:Pulmonary Langerhans cell histiocytosis (PLCH) is a rare sporadic cystic lung disease of unknown aetiology that is characterised by the infiltration and destruction of the wall of distal bronchioles by CD1a+ Langerhans-like cells. In adults, PLCH is frequently isolated and affects young smokers of both sexes. Recent multicentre studies have led to the more standardised management of patients in clinical practice. Smoking cessation is essential and is occasionally the only suitable intervention. Serial lung function testing is important because a significant proportion of patients may experience an early decline in forced expiratory volume in 1 s and develop airflow obstruction. Cladribine was reported to dramatically improve progressive PLCH in some patients. Its efficacy and tolerance are currently being evaluated. Patients who complain of unexplained dyspnoea with decreased diffusing capacity of the lung for carbon monoxide should be screened for pulmonary hypertension by Doppler echocardiography, which must be confirmed by right heart catheterisation. Lung transplantation is a therapeutic option for patients with advanced PLCH.The identification of the BRAFV600E mutation in approximately half of Langerhans cell histiocytosis lesions, including PLCH, and other mutations of the mitogen-activated protein kinase (MAPK) pathway in a subset of lesions has led to targeted treatments (BRAF and MEK (MAPK kinase) inhibitors). These treatments need to be rigorously evaluated because of their potentially severe side-effects.
Project description:Langerhans cell histiocytosis (LCH) is a rare neoplasm characterized by accumulation of histiocytes in various tissues. It has a wide clinical spectrum and its presentation may mimic clinical features of common diseases. High level of suspicion is required for early diagnosis. Here is a rare case of a rapidly aggressive LCH which first presented with right zygomatic swelling.
Project description: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.
Project description:Langerhans cell histiocytosis (LCH) has a broad spectrum of clinical behaviors; some cases are self-limited, whereas others involve multiple organs and cause significant mortality. Although Langerhans cells in LCH are clonal, their benign morphology and their lack (to date) of reported recurrent genomic abnormalities have suggested that LCH may not be a neoplasm. Here, using 2 orthogonal technologies for detecting cancer-associated mutations in formalin-fixed, paraffin-embedded material, we identified the oncogenic BRAF V600E mutation in 35 of 61 archived specimens (57%). TP53 and MET mutations were also observed in one sample each. BRAF V600E tended to appear in younger patients but was not associated with disease site or stage. Langerhans cells stained for phospho-mitogen-activated protein kinase kinase (phospho-MEK) and phospho-extracellular signal-regulated kinase (phospho-ERK) regardless of mutation status. High prevalence, recurrent BRAF mutations in LCH indicate that it is a neoplastic disease that may respond to RAF pathway inhibitors.
Project description:Erdheim-Chester disease (ECD) is a rare non-Langerhans cell histiocyte disorder most commonly characterized by multifocal osteosclerotic lesions of the long bones demonstrating sheets of foamy histiocyte infiltrates on biopsy with or without histiocytic infiltration of extraskeletal tissues. ECD can be difficult to diagnose since it is a very rare disease that can affect many organ systems. Diagnosis is based on the pathologic evaluation of involved tissue interpreted within the clinical context. Patients who have the BRAF V600E mutation are treated first line with vemurafenib. For those without the mutation with symptomatic ECD, conventional or PEGylated interferon alpha is recommended. For patients who are either intolerant or nonresponsive to interferon alpha, systemic chemotherapy with or without corticosteroids can be used. We present a rare case of Erdheim-Chester disease with concurrent Langerhans cell histiocytosis which occurs in only one fifth of the cases and often presents as a diagnostic and therapeutic challenge.
Project description:BackgroundTo investigate the magnetic resonance imaging (MRI) features of orbital Langerhans cell histiocytosis (LCH) to improve diagnostic accuracy.MethodsWe retrospectively reviewed clinical manifestations and MRI findings of 23 patients with histopathology-confirmed LCH of the orbit. The findings were evaluated for the following: (a) symptoms, (b) disease duration, (c) location, (d) configuration, (e) margin, (f) MR imaging signal intensity and enhanced performance.ResultsEighteen patients (78%) in our series were male, only five (22%) patients were female, and the mean age at presentation was 6.3 years. The common symptoms include swollen eyelids, exophthalmos, and a palpable mass. Fourteen patients presented with swollen eyelids and/or exophthalmos. Twenty-two cases involved unilateral orbits, and one case involved bilateral orbits. In our study, there was one patient with cough and expectoration, and one patient with polydipsia and polyuria. Lesions were located in the superior or superlateral orbital roof of seventeen patients (74%). Lesions formed masses or irregular shapes. The 12 out of 23 (52.2%) cases appeared heterogeneous isointense and 10 out of 23 (43.5%) cases showed iso-hypointense on T1-weighted imaging, there were 15 out of 23 (65.2%) cases showed hyper-hypointense mixed signals on T2-weighted imaging. 7 cases found patchy hyperintense signal on T1WI, and 11 cases showed markedly hyperintense signal near the edge of lesions on T2WI. After enhancement, 21 out of 23 (91.3%) cases lesions presented marked enhancement at the edges and the surrounding tissues, and with heterogeneous obvious enhancement of the lesion center. Besides, four cases lesions were surrounded by a low circular signal.ConclusionThere were several characteristics MRI features that can provide crucial information for clinicians and improve our understanding and the diagnostic accuracy of the orbital LCH.
Project description:Background and aimsLiver involvement portends poor prognosis in adults. We aimed to characterize the clinical features, liver function tests, radiologic findings, molecular profiles, therapeutic approaches and outcomes of adults patients with Langerhans cell histiocytosis (LCH) with liver involvement.MethodsWe conducted a retrospective analysis of all adults with LCH (≥ 18 years) seen at Peking Union Medical College Hospital (Beijing, China) between January 2001 and December 2022.ResultsAmong the 445 newly diagnosed adults with LCH, 90 patients had liver involvement at diagnosis and 22 patients at relapse. The median age was 32 years (range, 18-66 years). Of 112 evaluable patients, 108 had full liver function testing, including alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase (ALP), γ-glutamyl transpeptidase (GGT), and total bilirubin and albumin. Elevated ALP was seen in 63.0% and GGT in 86.1%; 14.8% had elevated bilirubin. Next-generation sequencing of 54 patients revealed frequent BRAFN486_P490 (29.6%), BRAFV600E (18.5%), and MAP2K1 (14.8%).OutcomesAfter a median 40 months' follow-up (range 1-168 months), 3-year progression-free survival (PFS) and overall survival were 49.7% and 86.6% respectively. In multivariable analyses, ≥3 abnormal liver function tests (HR 3.384, 95% CI 1.550-7.388, P = .002) associated with inferior PFS; immunomodulatory drug therapy (HR 0.073, 95% CI, 0.010-0.541, P = .010) correlated with superior PFS versus chemotherapy.ConclusionsIn summary, elevated GGT and ALP were common in adults with LCH liver involvement. Greater than equal to 3 abnormal liver function tests predicted poor outcomes. Immunomodulatory drug therapy was associated with favorable progression-free survival compared to chemotherapy.
Project description:Pulmonary Langerhans Cell Histiocytosis (PLCH) is a diffuse lung disease that primarily affects young adults, with cigarette smoking playing a significant role in developing the disease. Patients with PLCH present with characteristic CT chest findings of small irregular nodules and upper zone cysts. Previously, larger nodules greater than 10 mm and cavitation have only been reported a few times in the literature. We describe the case of a 69-year-old male who presented with dyspnea, non-productive cough and weight loss, who was found to have multiple cavitary nodules on CT imaging of the chest. Histopathologic sampling of the lung revealed Langerhans cells which stained positive for S100 and CD1a, consistent with a diagnosis of PLCH. The patient was counselled to quit smoking as the mainstay of treatment. In 3-month follow-up his symptoms had largely resolved, with evidence of decreased nodule size on repeat CT imaging.