Clinical features and treatment outcomes of liver involvement in paediatric Langerhans cell histiocytosis.

Langerhans cell histiocytosis (LCH) is the most common histiocytic disorder in children, and liver involvement in LCH is rare. This retrospective study reported the clinical features and prognosis of patients with hepatic LCH. Liver involvement was defined by histopathological findings, liver dysfunction or abnormalities, or ultrasound imaging. A total of 130 patients (14.5%) with hepatic LCH out of 899 in the LCH population were enrolled. Patients with liver involvement had greater frequencies of skin, lung, hearing system, and haematologic system involvement, and hemophagocytic lymphohistiocytosis (P<0.001, 0.001, 0.002, 0.009, and <0.001, respectively). Overall survival and progression-free survival were lower in LCH patients with liver involvement than in those without liver involvement (P<0.001 and <0.001). In patients with liver involvement, the overall survival (OS) and progression-free survival (PFS) rates were lower in patients with cholangitis than in those without cholangitis (P<0.020 and 0.030). For the treatment response, the response rate of hepatic LCH patients to initial first-line therapy (n=89) was 22.5%. However, there was no significant difference in the response rate or recurrence rate between patients who shifted from first-line treatment to second-line treatment (n=29) or to targeted therapy (n=13) (P=0.453 and 1.000). The response rate of hepatic LCH patients who received initial second-line therapy (n=13) was 38.5%. Two of these patients subsequently experienced bone recurrence. The response rate of hepatic LCH patients who received initial targeted therapy (n=16) was 75.0%. Three patients subsequently experienced recurrence, including 2 in the bone and 1 in the liver and skin. A total of 39.3% of patients who received second-line treatment had severe myelosuppression (grade III-IV), and 50.8% had varying degrees of gastrointestinal events, whereas there was no severe toxicity in patients who received first-line treatment and targeted therapy. Four patients underwent liver transplantation because of liver cirrhosis. The patients' liver disease improved within a follow-up period of 18-79 months. This study demonstrated that LCH with liver involvement, especially cholangitis, indicates a poor prognosis. Targeted therapy provides a good treatment response and less toxicity. However, it may relapse after withdrawal. Liver transplantation is still a reliable salvage option for patients with end-stage liver disease.

Langerhans Cell Histiocytosis in Sphenoid Sinus: Uncommon Bone Involvement.

BACKGROUND Langerhans cell histiocytosis (LCH) is a rare and uncontrolled proliferation of dendritic cells of myeloid origin. The incidence of LHC was estimated at 5 cases per million children ages 0-15 years old. The most common places for this tumor are the jaw, vertebra, pelvis, and the extremities. The disease with multisystem involvement can present a mortality rate of 20% and one-third of children have multisystem involvement. We present a case with unusual bone involvement of the anterior cranial base with a challenging diagnosis and a complex surgical approach. CASE REPORT We report the case of a 6-year-old boy who manifested the disease with daily holocranial headache, worse in the frontal region and refractory to analgesia for 10 days, strabismus homonymous, diplopia, and right palpebral ptosis. The tumor affected the sphenoid sinus, internal carotid artery, and sella turcica, and made contact with the pituitary gland. A joint surgery with Otorhinolaryngology and Neurosurgery was performed by nasal endoscopic access to the skull base by means of the right medial turbinectomy (for the access) and right sphenoid opening, septectomy and opening of the left sphenoid to work with 4 hands and, after resection of lesion, inside the sphenoid. CONCLUSIONS This patient had rare bone involvement from LCH and atypical clinical presentation next to the important and delicate structures of the anterior skull base, but had a satisfactory outcome.

From mutation to management: Advancing Langerhans cell histiocytosis treatment through combination therapies.

The treatment landscape for relapsed Langerhans cell histiocytosis (LCH) is fraught with uncertainty due to a scarcity of data. Karri et al.'s study provides promising evidence that combining MAPK pathway inhibitors with chemotherapy could improve outcomes, even for patients with multiple relapses. Although larger studies are needed, this approach suggests a shift towards more aggressive, potentially curative strategies in the management of LCH. Commentary on: Karri et al. Clinical, radiological and molecular responses to combination chemotherapy with MAPK pathway inhibition in relapsed and refractory Langerhans cell histiocytosis. Br J Haematol 2024;204:1882-1887.

Juvenile xanthogranuloma manifesting with LCH-associated neurodegenerative disease-like radiological findings.

Here, we describe two patients with juvenile xanthogranuloma (JXG) manifesting with Langerhans cell histiocytosis (LCH)-associated neurodegenerative disease (ND)-like radiological findings. One patient showed typical radiological abnormalities at onset, which worsened with progressing central nervous system symptoms 7 years after LCH-oriented chemotherapy. Another showed spontaneous regression of clinical symptoms, with a transient radiological change 1 year after salvage chemotherapy for recurrence of JXG. These data regarding JXG-associated ND will facilitate future investigation of the disease, as well as development of therapeutic interventions.

[Diffuse cystic lung disease]. / Cystische Lungenerkrankungen.

INTRODUCTION: Diffuse cystic lung disease (DCLD) represents a heterogeneous group of conditions, typically characterized by the presence of multiple thin-walled, predominantly round parenchymal lucencies. The increased accessibility of computed tomography (CT) underscores the growing relevance of a relatively rare group of diseases as more clinicians are confronted with the presence of multiple lung cysts on the chest CT scan. Although the etiology of these conditions is very diverse, the focus of the differential diagnosis revolves around four primary causative factors - Lymphangioleiomyomatosis (LAM), Pulmonary Langerhanscell histiocytosis (PLCH), Birt-Hogg-Dubé (BHD) and lymphoid interstitial pneumonia (LIP). Achieving an accurate diagnosis poses a challenge and typically necessitates lung biopsies; however, it is crucial for ensuring proper management.

Increased AXLhigh myeloid cells as pathognomonic marker in Langerhans cell histiocytosis and Langerin expression dependence of mTOR inhibition.

Langerhans cell histiocytosis (LCH) is characterized by an expansion and accumulation of pathological histiocytes expressing langerin (CD207) and CD1a in different organs under an inflammatory milieu. The origin of pathognomonic precursors of LCH is widely debated, but monocytes and pre-dendritic cells (pre-DC) play a significant role. Remarkably, we found an expansion of AXLhigh cells in the CD11c+ subset of patients with active LCH, which also express the pathognomonic CD207 and CD1a. Moreover, we obtained a monocyte-derived LC-like (mo-LC-like) expressing high levels of AXL when treated with inflammatory cytokine, or plasma of patients with active disease. Intriguingly, inhibiting the mTOR pathway at the initial stages of monocyte differentiation to LC-like fosters the pathognomonic LCH program, highly increasing CD207 levels, together with NOTCH1 induction. We define here that AXLhigh could also be taken as a strong pathognomonic marker for LCH, and the release of Langerin and NOTCH1 expression depends on the inhibition of the mTOR pathway.

Exploration of treatment in childhood Langerhans cell histiocytosis based on inflammatory and malignant symptoms: a pilot study.

BACKGROUND: Multisystem childhood Langerhans cell histiocytosis (LCH) patients, especially those with risk organ (RO) involved, had not been satisfactorily treated under the international traditional schemes as high incidences of reactivation with late sequelae were largely reported. Over years, we have observed that LCH patients with varied clinical symptoms responded differently to different drugs, suggesting the current grouping strategies based only on the number of organs involved might be inadequate. LCH has been defined as an inflammatory myeloid tumor, thus this study has innovatively divided LCH pediatric patients into inflammatory or malignant symptoms group, and given different intensity treatment regimens to different groups. AIM: This clinical study aimed to explore a more appropriate patient grouping system according to the LCH symptom presentations and examine the clinical outcomes of treatment strategies in different groups. METHODS: According to the clinical manifestations, 37 cases of children were divided into Group A (only inflammatory symptoms) and Group B (malignant symptoms with or without inflammatory symptoms). Patients in Group A and B were initially treated with vindesine (VDS) and methylprednisolone (PSL), and VDS, PSL, pirarubicin (THP) and cyclophosphamide (CTX), respectively. Treatment responses were evaluated six weeks after the induction therapy in all patients, and the criteria were disease status and clinical scores of symptoms. RESULTS: Pre- and post-treatment scores were 1.22 ± 0.547 and 0.00 ± 0.00 in Group A, and 14.79 ± 1.686 and 1.00 ± 1.563 in Group B, respectively. All patients had subsequentlly received maintenance therapy without progressive disease. The 4-year overall survival (OS) rate was 100% in both groups and the 4-year event-free survival (EFS) was 94.4% in Group A and 89.5% in Group B, respectively. There were no obvious adverse events (AE) in Group A, whereas the main AE in Group B were alopecia and non-lethal hematological toxicity. CONCLUSION: Stratification according to patients' clinical symptoms, with low-intensity treatment for inflammatory symptoms (mild manifestations) and intensive treatment with multiple drugs for malignant symptoms (severe manifestations), is a positive exploration that simplifies stratification method, achieves good long-term remission of the disease, and obtains a higher survival rate and quality of life, which seemed to be more appropriate for LCH patients.

The plasma-soluble CSF1R level is a promising prognostic indicator for pediatric Langerhans cell histiocytosis.

Langerhans cell histiocytosis (LCH) is a rare hematologic neoplasm characterized by the clonal proliferation of Langerhans-like cells. Colony-stimulating factor 1 receptor (CSF1R) is a membrane-bound receptor that is highly expressed in LCH cells and tumor-associated macrophages. In this study, a soluble form of CSF1R protein (sCSF1R) was identified by plasma proteome profiling, and its role in evaluating LCH prognosis was explored. We prospectively measured plasma sCSF1R levels in 104 LCH patients and 10 healthy children using ELISA. Plasma sCSF1R levels were greater in LCH patients than in healthy controls (p < .001) and significantly differed among the three disease extents, with the highest level in MS RO+ LCH patients (p < .001). Accordingly, immunofluorescence showed the highest level of membrane-bound CSF1R in MS RO+ patients. Furthermore, the plasma sCSF1R concentration at diagnosis could efficiently predict the prognosis of LCH patients treated with standard first-line treatment (AUC = 0.782, p < .001). Notably, dynamic monitoring of sCSF1R levels could predict relapse early in patients receiving BRAF inhibitor treatment. In vitro drug sensitivity data showed that sCSF1R increased resistance to Ara-C in THP-1 cells expressing ectopic BRAF-V600E. Overall, the plasma sCSF1R level at diagnosis and during follow-up is of great clinical importance in pediatric LCH patients.

Intestinal Langerhans cell histiocytosis presenting with symptoms similar to inflammatory bowel disease: a case report.

Background: Langerhans cell histiocytosis is a rare disease characterized by the abnormal proliferation of Langerhans cells within a single organ or multiple organs. This case report aims to improve the knowledge of the presentation of gastrointestinal Langerhans cell histiocytosis to facilitate the diagnosis and management of this rare disorder. Case presentation: A 19-month-old female presented with repeatedly mucinous bloody stools. The abdominal ultrasound revealed a slightly enlarged spleen. The initial colonoscopy revealed chronic enteritis with a very early onset inflammatory bowel disease. After anti-inflammatory treatment without improvement, an intestinal biopsy was performed at The Forth Affiliated Hospital of Zhejiang University. The final intestinal biopsy and histopathology examination confirmed the presence of Langerhans cell histiocytosis. After diagnosis, additional lung and head imaging examinations revealed no abnormalities. Her condition improved gradually after being treated with chemotherapy (vincristine and prednisone) and molecular-targeted drug(dalafinil) treatment. Conclusion: The clinical symptoms of Langerhans cell histiocytosis involving the gastrointestinal tract are not specific and may resemble symptoms observed in inflammatory bowel disease and other primary gastrointestinal tumors. Therefore, in cases of infants presenting with inflammatory gastrointestinal symptoms that do not resolve after treatment, a biopsy is essential to obtain a differential diagnosis.

Clofarabine monotherapy in aggressive, relapsed and refractory Langerhans cell histiocytosis.

Over 50% of patients with systemic LCH are not cured with front-line therapies, and data to guide salvage options are limited. We describe 58 patients with LCH who were treated with clofarabine. Clofarabine monotherapy was active against LCH in this cohort, including heavily pretreated patients with a systemic objective response rate of 92.6%, higher in children (93.8%) than adults (83.3%). BRAFV600E+ variant allele frequency in peripheral blood is correlated with clinical responses. Prospective multicentre trials are warranted to determine optimal dosing, long-term efficacy, late toxicities, relative cost and patient-reported outcomes of clofarabine compared to alternative LCH salvage therapy strategies.

Clinical, radiological and molecular responses to combination chemotherapy with MAPK pathway inhibition in relapsed and refractory Langerhans cell histiocytosis.

Optimal therapeutic approaches for advanced Langerhans cell histiocytosis (LCH) are not known. We assessed the safety and efficacy of combined chemotherapy with MAPK pathway inhibition in 10 patients with refractory systemic disease and/or LCH-associated neurodegeneration. Overall response rate was 9/10 (90%) for the entire cohort: 5/5 (100%) for patients with systemic disease and 6/7 (86%) for patients with central nervous system disease. BRAFV600E+ peripheral blood fraction decreased in 5/6 (83%). Toxicities included fever, skin rash, myalgias, neuropathy, cytopenias and hypocalcaemia. Prospective trials are required to optimize combination strategies, determine potential to achieve cure and compare outcomes to chemotherapy or MAPK inhibitor monotherapy.

Langerhans cell histiocytosis in children with refractory diarrhoea and hypoalbuminaemia as the initial presentation: two case reports and a literature review.

Langerhans cell histiocytosis (LCH) involving the gastrointestinal tract is a rare condition for which clinical experience is limited. We describe the cases of two patients who initially presented with chronic diarrhoea, hypoproteinaemia, and intermittent fever. These findings suggest that in cases of refractory diarrhoea accompanied by recurrent hypoalbuminaemia, especially with abdominal rash, LCH should be considered. Gastrointestinal endoscopy, biopsy, and imaging studies are essential for obtaining a definitive diagnosis. This approach might be helpful for the early recognition of gastrointestinal tract involvement in LCH.

Treatment of congenital Langerhans cell histiocytosis with cobimetinib.

We report a case of congenital multisystem Langerhans cell histiocytosis with cutaneous and hematopoietic involvement. After the failure of first-line (vinblastine and prednisolone) and second-line (vincristine and cytarabine) therapies, treatment with cobimetinib, a mitogen-activated protein kinase (MEK) inhibitor, led to the remission of disease and a sustained response after 11 months of ongoing treatment. Protein kinase inhibitors targeting BRAF or MEK could represent a promising future therapeutic option, also in children with LCH.

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.

Coexistence of Langerhans Cell Histiocytosis and Ganglioneuroblastoma Revealed by 18 F-FDG PET/CT in a Pediatric Patient.

ABSTRACT: Coexistence of Langerhans cell histiocytosis and ganglioneuroblastoma is rare and seldom reported in the literature. A 3-year-old girl with Langerhans cell histiocytosis underwent 18 F-FDG PET/CT imaging for staging, which demonstrated significant 18 F-FDG accumulation in the mandibles. Unexpectedly, a mild hypermetabolic soft mass was detected in the upper retroperitoneum. Results of surgical pathology of the abdominal mass were consistent with ganglioneuroblastoma.

Identification and characterization of stromal-like cells with CD207+/low CD1a+/low phenotype derived from histiocytic lesions - a perspective in vitro model for drug testing.

BACKGROUND: Histiocytoses are rare disorders manifested by increased proliferation of pathogenic myeloid cells sharing histological features with macrophages or dendritic cells and accumulating in various organs, i.a., bone and skin. Pre-clinical in vitro models that could be used to determine molecular pathways of the disease are limited, hence research on histiocytoses is challenging. The current study compares cytophysiological features of progenitor, stromal-like cells derived from histiocytic lesions (sl-pHCs) of three pediatric patients with different histiocytoses types and outcomes. The characterized cells may find potential applications in drug testing. METHODS: Molecular phenotype of the cells, i.e. expression of CD1a and CD207 (langerin), was determined using flow cytometry. Cytogenetic analysis included GTG-banded metaphases and microarray (aCGH) evaluation. Furthermore, the morphology and ultrastructure of cells were evaluated using a confocal and scanning electron microscope. The microphotographs from the confocal imaging were used to reconstruct the mitochondrial network and its morphology. Basic cytophysiological parameters, such as viability, mitochondrial activity, and proliferation, were analyzed using multiple cellular assays, including Annexin V/7-AAD staining, mitopotential analysis, BrdU test, clonogenicity analysis, and distribution of cells within the cell cycle. Biomarkers potentially associated with histiocytoses progression were determined using RT-qPCR at mRNA, miRNA and lncRNA levels. Intracellular accumulation of histiocytosis-specific proteins was detected with Western blot. Cytotoxicyty and IC50 of vemurafenib and trametinib were determined with MTS assay. RESULTS: Obtained cellular models, i.e. RAB-1, HAN-1, and CHR-1, are heterogenic in terms of molecular phenotype and morphology. The cells express CD1a/CD207 markers characteristic for dendritic cells, but also show intracellular accumulation of markers characteristic for cells of mesenchymal origin, i.e. vimentin (VIM) and osteopontin (OPN). In subsequent cultures, cells remain viable and metabolically active, and the mitochondrial network is well developed, with some distinctive morphotypes noted in each cell line. Cell-specific transcriptome profile was noted, providing information on potential new biomarkers (non-coding RNAs) with diagnostic and prognostic features. The cells showed different sensitivity to vemurafenib and trametinib. CONCLUSION: Obtained and characterized cellular models of stromal-like cells derived from histiocytic lesions can be used for studies on histiocytosis biology and drug testing.

Langerhans cell histiocytosis of the skull in 23 children.

OBJECTIVE: To explore the clinical features, diagnosis, treatment and prognosis of Langerhans cell histiocytosis (LCH) of the skull in children. METHODS: This study retrospectively summarized the clinical manifestations, treatment methods and follow-up status of children with skull LCH who were admitted to the Department of Neurosurgery of Shanghai Children's Hospital from January 2014 to June 2021. RESULTS: A total of 23 patients confirmed by histology as LCH received hospitalization treatment, including 14 males and 9 females, aged (5.76 ± 3.86) years old. The clinical manifestations were mostly incidentally discovered head masses that gradually enlarged (19 cases, 82.61%). Only 2 cases are affected by multiple systems, while the rest are affected by single systems. 9 patients were involved in multiple skull lesions, and 14 patients had local skull lesions. All patients underwent surgical intervention, with 17 patients undergoing total resection and 6 patients undergoing biopsy. 21 patients received chemotherapy after surgery. The median follow-up was 2.46 years (range 0.33-6.83 years). 21 patients had their symptoms and signs under control or even resolved, and 2 patients experienced recurrence during follow-up. The overall control rate reached 91.30%. CONCLUSION: Personalized treatment plans according to different clinical types. Regular outpatient follow-up is crucial to monitor disease recurrence and late effects.

Metagenomic sequencing expedites diagnosis of disseminated BCG in an infant with BRAFV600E mutation.

INTRODUCTION: Disseminated bacillus Calmette-Guérin (BCG) disease is a rare but serious BCG complication in children. Early diagnosis and timely interventions are essential to improve prognosis. However, its manifestations can closely mimic those of Langerhans cell histiocytosis (LCH), which usually leads to a high rate of misdiagnoses. Herein we report the first case of successful application of biopsy tissue metagenomic next-generation sequencing (mNGS) in the differential diagnosis of disseminated BCG disease and LCH. CASE STUDY: A 5-month-old female infant was transferred to our center for the treatment of paroxysmal cough, intermittent hematochezia and trunk rash. Examination on admission showed moderate anemia, erythropenia, thrombocytopenia and hepatosplenomegaly. The immunohistochemistry of her intestinal biopsy samples showed CD1a (+) and Langerin (+). Genetic testing of both peripheral blood and bone marrow samples suggested BRAFV600E mutation. Hence, she was initially diagnosed with LCH. However, no improvement was observed after a course of systemic chemotherapy. The left axillary lymph node and colonic mucosal biopsy specimens were sent for mNGS which resulted in sequence reads of Mycobacterium bovis-BCG. Triple antimycobacterial therapy was started according to the diagnosis. RESULTS: The diagnosis of this case was corrected as disseminated BCG disease by mNGS. Currently, she is doing well clinically and continues to follow-up at our outpatient clinic. CONCLUSIONS: This case suggests that mNGS is a valuable tool in the differential diagnosis of disseminated BCG disease and LCH, which can improve the early diagnosis rate of disseminated BCG disease.