Pulmonary Langerhans' cell histiocytosis: radiologic resolution following smoking cessation

Smoking-Related Interstitial Lung Disease: Historical Perspective and Advances in the Twenty-first Century

In the twenty- first century, there is widespread agreement that in addition to lung cancer, emphysema, and chronic bronchitis, cigarette smoking causes accumulation of pigmented macrophages, interstitial fibrosis, and Langerhans cell proliferation in various permutations. These histologic changes remain subclinical in some patients and produce clinical manifestations and imaging abnormalities in others. Debate surrounds terminology of these lesions, which are often grouped together under the umbrella of "smoking-related interstitial lung disease." This review summarizes modern concepts in our understanding of these abnormalities and explains how the recognition of smoking-related interstitial fibrosis has advanced the field.

The world of rare interstitial lung diseases

The world of rare interstitial lung diseases (ILDs) is diverse and complex. Diagnosis and therapy usually pose challenges. This review describes a selection of rare and ultrarare ILDs including pulmonary alveolar proteinosis, pulmonary alveolar microlithiasis and pleuroparenchymal fibroelastosis. In addition, monogenic ILDs or ILDs in congenital syndromes and various multiple cystic lung diseases will be discussed. All these conditions are part of the scope of the European Reference Network on rare respiratory diseases (ERN-LUNG). Epidemiology, pathogenesis, diagnostics and treatment of each disease are presented.

Pulmonary Langerhans Cell Histiocytosis That Progressed from a Single-system to a Multisystem Form despite Smoking Cessation

A 36-year-old Japanese man presented with cavities and nodular shadows in the lower lobes of his lungs and osteolytic lesions in the thoracic spine. He was diagnosed with multisystem Langerhans cell histiocytosis (LCH). Three years earlier, he had been noted to have small cavities and granular lesions noted in the upper lobes of his lungs, which later improved with smoking cessation. It was likely that his single-system pulmonary LCH (PLCH) progressed to multisystem LCH despite smoking cessation. Relapse or progression may occur in cases where PLCH lesions improve after smoking cessation. Thus, close follow-up is vital.

High-Resolution Computed Tomography of Cystic Lung Disease

The cystic lung diseases (CLD) are characterized by the presence of multiple, thin-walled, air-filled spaces in the pulmonary parenchyma. Cyst formation may occur with congenital, autoimmune, inflammatory, infectious, or neoplastic processes. Recognition of cyst mimics such as emphysema and bronchiectasis is important to prevent diagnostic confusion and unnecessary evaluation. Chest CT can be diagnostic or may guide the workup based on cyst number, distribution, morphology, and associated lung, and extrapulmonary findings. Diffuse CLD (DCLDs) are often considered those presenting with 10 or more cysts. The more commonly encountered DCLDs include lymphangioleiomyomatosis, pulmonary Langerhans' cell histiocytosis, lymphoid interstitial pneumonia, Birt-Hogg-Dubé syndrome, and amyloidosis/light chain deposition disease.

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.

Spontaneous pneumothorax with pulmonary Langerhans cell histiocytosis (PLCH) in an adult heavy cigarette smoker-A case report

Pulmonary Langerhans cell histiocytosis is a rare disease caused by the proliferation of CD1a‐positive histiocyte‐like cells infiltrating the lung's interstitial layer. Most cases affect young to middle‐aged persons, especially adult heavy cigarette smokers. A 49‐year‐old male heavy smoker (40 pack‐year), with non‐productive cough, dyspnoea and desaturation, presented with a right‐sided pneumothorax on chest x‐ray with total atelectasis. Chest computed tomography (CT) revealed bilateral multiple thick‐walled infiltrated cysts and multiple ground‐glass nodules throughout the entire lung. Surgery with minimal invasive thoracoscopic lung biopsy and pleurodesis was performed. Pathology showed histiocyte‐like cells aggregates in the pulmonary parenchyma. Immunohistochemical stain demonstrated CD1a(+), S100(+) and CD68(+). After 3 months of smoking cessation, clear improvement was evidenced with a chest CT showing bilateral multiple thin‐walled rounded cysts and multiple ground‐glass nodules that are smaller in size and decreased in numbers. Early minimal invasive thoracoscopic lung biopsy and pleurodesis can also be a choice if the development of secondary spontaneous pneumothorax occurs.

Limited Utility of Chemotherapy for Pulmonary Langerhans Cell Histiocytosis Due to Unclear Diagnostic Criteria

Pulmonary Langerhans cell histiocytosis (PLCH) is a rare interstitial lung disease that affects young adults and is typically misdiagnosed or presents concurrently with more common respiratory conditions such as asthma or chronic obstructive lung disease (COPD). A combination of imaging, tissue biopsy, and clinical presentation is used for diagnosis since no definitive criteria have been established. Current standards are based on vague descriptors such as clustering of histologic markers but lack quantitative analysis. In this case report, we present a patient who was initially diagnosed with PLCH, but the lack of unanimity for diagnostic requirements led to conflicting diagnoses between institutions which may have prevented optimal care for the patient. The disparity limited new, alternative therapies for our patient that may have been beneficial since he was clinically not improving with smoking cessation and standard of care for obstructive lung diseases. However, quantitative endorsements for tissue analysis, such as requiring more than 30 Cd-1a stained Langerhans cells per high power field (HPF), may reduce discrepancies associated with current techniques. It is imperative that clear standards are established due to the unique treatment these patients require that is atypical from other pulmonary diseases such as asthma and COPD. New chemotherapeutic regimens such as cladribine and vemurafenib require oncologic care and have more broad side effects than typical pulmonary treatments, which emphasize the need for accurate diagnoses before starting treatment. Existing standards have created circumstances where PLCH is a differential but cannot be ruled out due to unclear criteria and limited research. 

Epidemiology, Pathogenesis, and Clinical Approach in Group 5 Pulmonary Hypertension

Pulmonary hypertension (PH) is recognized to be associated with a number of comorbid conditions. Based on these associations, PH is classified into 5 groups, considering common pathophysiologic drivers of disease, histopathologic features, clinical manifestations and course, and response to PH therapy. However, in some of these associated conditions, these characteristics are less well-understood. These include, among others, conditions commonly encountered in clinical practice such as sarcoidosis, sickle cell disease, myeloproliferative disorders, and chronic kidney disease/end stage renal disease. PH in these contexts presents a significant challenge to clinicians with respect to disease management. The most recent updated clinical classification schemata from the 6th World Symposium on PH classifies such entities in Group 5, highlighting the often unclear and/or multifactorial nature of PH. An in-depth review of the state of the science of Group 5 PH with respect to epidemiology, pathogenesis, and management is provided. Where applicable, future directions with respect to research needed to enhance understanding of the clinical course of these entities is also discussed.

Psychological features of adult patients with langerhans cell histiocytosis

BACKGROUND

The prevalence of psychological symptoms and the co-occurrence of substance abuse disorders in adult patients with Langerhans cell histiocytosis (LCH) has not been previously explored. We aimed to use validated scales to evaluate depression and anxiety symptoms experienced by adult LCH patients.

METHODS

In this cross-sectional study, all consecutive adult LCH patients seen at our national reference center between January 2012 and January 2013 were asked to complete the following instruments: the Hospital Anxiety and Depression scale (HADS); Barratt Impulsiveness Scale, Version 10 (BIS-10); and Cannabis Use Disorders Identification Test (CUDIT). Self-reported scores on these scales were used to determine the point prevalence of clinically significant psychological symptoms and substance use disorders in LCH patients. Patient profiles in terms of psychological features were assessed by principal component analysis including the HADS and BIS-10 instruments values, followed by hierarchical clustering. Fisher exact tests and Wilcoxon tests were used to examine the associations between disease-related parameters and high levels of anxiety and impulsivity.

RESULTS

Seventy-one adult LCH patients, mainly with pulmonary LCH (PLCH), completed the evaluations. Clinically significant anxiety and depression symptoms were reported by 22 (31%) and 4 (6%) subjects, respectively. Impulsivity was detected in 14% (10/71) of the patients. Seventeen percent (12/71) of the patients used cannabis on a regular basis, with 50% of these individuals (6/12) exhibiting scores consistent with cannabis use disorder. Three derived clusters of patients were identified in the principal component analysis; these patient clusters differed in successful weaning from tobacco at the time of evaluation (p = 0.03). In univariate analyses, isolated PLCH and the use of psychotropic treatments were statistically associated with clinically significant anxiety symptoms.

CONCLUSIONS

High levels of anxiety and impulsivity are common in adult patients with LCH. The consequences of these symptoms for the management of LCH patients warrant further evaluation.

Adult pulmonary Langerhans cell histiocytosis might consist of two distinct groups: isolated form and extrapulmonary recidivism type

Background

Adult pulmonary Langerhans cell histiocytosis (PLCH) is a rare form of Langerhans cell histiocytosis (LCH) that typically occurs in cigarette smokers. The clinical course of PLCH is unpredictable; the disease may resolve spontaneously, or lead to multi-organ failure and death. To better understand this idiopathic disease, we retrospectively overviewed a cohort of Asian patients with PLCHs.

Methods

Herein, we have provided detailed clinicopathological features and molecular findings of PLCHs in a Southwestern Chinese population, including the expressions of apoptotic protein P16, programmed cell death 1 (PD-1), and programmed cell death-ligand 1 (PD-L1). Importantly, the BRAF^V600E mutation was observed in this cohort.

Results

In accordance with the follow up data, the cohort was subdivided into two groups, an isolated pulmonary group and extrapulmonary recidivism group. Among the isolated group, the participants were predominantly young males (<40 years old), with a history of smoking, respiratory symptoms (cough and difficulty breathing), showed more cystic lesions in computed tomography (CT) scanning, had more cellular Langerhans granulomas under the microscope, overexpression of P16 (66.7%), high PD-1 (100%) and low PD-L1 (33.3%) expressions, and no BRAF^V600E mutation was detected. In contrast, the extrapulmonary recidivism group showed significantly older age (>40 years old), recurrent spontaneous pneumothorax, more nodular changes in CT scanning, more interstitial fibrosis histologically, expression rates of 100% of P16, 66.7% of PD-1, and 33.3% of PD-L1; and importantly, BRAF^V600E mutation was detected in 33.3% of this subdivision.

Conclusions

We found that adult PLCH might consist of two distinct groups: an isolated form and extrapulmonary recidivism PLCH. Overexpression of P16 could be a diagnostic biomarker for PLCH. An extremely low mutation rate of the BRAF gene in adult PLCH in our cohort indicated that there might be other pathogeneses for this disease among Asian patients.

Pulmonary Langerhans Cell Histiocytosis Associated with Bronchogenic Carcinoma

Pulmonary Langerhans cell histiocytosis (PLCH, pulmonary eosinophilic granuloma) is a rare disease of clonal dendritic cells that primarily affects adults who smoke cigarettes. PLCH association with other malignancies is rarely reported. Herein, an unusual case of PLCH is presented with synchronous lung adenocarcinoma. A 76-year-old woman and chronic smoker was admitted for persistent dyspnea and productive cough, and had a left lower lung mass detected by computed tomography. She underwent bronchoscopy with biopsies. Histopathological analysis was negative, but cultures grew Mycobacterium avium complex. She subsequently underwent lobectomy and was found to have papillary adenocarcinoma with PLCH in the surrounding lung nodules. 

Pulmonary Langerhans cell histiocytosis in cats and a literature review of feline histiocytic diseases

OBJECTIVES

The aim of this study was to report the clinical, radiographic and pathological features of pulmonary Langerhans cell histiocytosis in four cats, and carry out a literature review of feline histiocytic diseases.

METHODS

Necropsy reports archived at the Department of Veterinary Pathology of the Federal University of Rio Grande do Sul were reviewed. The clinical information was then obtained from the clinical records at the Veterinary Hospital. Routine samples had been collected during necropsy, fixed in 10% formalin, routinely processed for histology, and stained with hematoxylin and eosin. Samples of lung were submitted for bacterial and fungal culture. Tissue sections of lung underwent immunohistochemical testing for vimentin, pancytokeratin, CD18, CD3, CD79αcy, E-cadherin and Iba1.

RESULTS

This disease affected mixed breed cats aged 7-14 years. Clinical signs consisted of severe mixed inspiratory and expiratory restrictive dyspnea, lethargy and anorexia. Thoracic radiographs revealed different lesion profiles, predominantly of an interstitial and alveolar pattern. Grossly, the lungs were diffusely firm and did not collapse. The pleural surface was bright and irregular due to multifocal-to-coalescent, well-demarcated, white, firm nodules that also extended into and obliterated the pulmonary parenchyma. Histological changes were characterized by poorly demarcated infiltration with histiocytic cells arranged in cohesive groups within the alveolar, bronchiolar and bronchial spaces. Histiocytic cells had intense cytoplasmic immunolabeling for vimentin and Iba1, and robust membrane immunolabeling with CD18 and E-cadherin; these cells were negative for CD3, CD79αcy and pancytokeratin in all cases.

CONCLUSIONS AND RELEVANCE

This article confirms that pulmonary Langerhans cell histiocytosis is a rare disease that occurs in middle-aged to older cats and causes widespread involvement of the pulmonary parenchyma, inducing acute or chronic, progressive respiratory disease characterized by mixed restrictive dyspnea that eventually leads to death. While a definitive clinical diagnosis is challenging, the nodular appearance of the pulmonary changes, together with the histological and immunohistochemistry findings, suffice for diagnostic confirmation of pulmonary Langerhans cell histiocytosis.

Pneumothorax in Patients with Pulmonary Langerhans Cell Histiocytosis

Introduction

Pneumothorax often develops in pulmonary Langerhans cell histiocytosis (PLCH), but some patients take a long time to be correctly diagnosed.

Objectives

This study assessed the frequency of pneumothorax in PLCH and analysed the role of chest computed tomography (CT) in the prompt diagnosis.

Patients and material

Of the 90 patients with PLCH seen from 2000 to 2015, 29 (32%) had pneumothorax as the initial finding. In this group, 18 (62%) patients were diagnosed within 1 month, whereas the diagnosis was delayed for 4–120 months in 11 (38%) patients.

Results

Patients who had pneumothorax as the initial sign of PLCH tended to be younger (mean age 27.7 ± 7.92 vs. 39.9 ± 13.21 years; P = 0.0001), male (69% vs. 43%; P = 0.028), smoked less (mean pack/years 8.4 ± 6.85 vs. 19 ± 17.16; P = 0.003), and had a significantly lower mean FVC (77.96 ± 19.62 vs. 89.47 ± 21.86% pred.; P = 0.015) and FEV₁ (68.6 ± 19.93 vs. 79.4 ± 21.48% pred.; P = 0.03 than patients who had no pneumothorax. Recurrent pneumothorax was diagnosed more frequently in the group with a delayed diagnosis (82% vs. 39%; P = 0.02). CT was performed in all of the patients who were diagnosed promptly, but in none of the patients with a delayed diagnosis.

Conclusions

Patients who had pneumothorax as the initial sign of PLCH were younger, more frequently men, and had greater respiratory impairment than those who had no pneumothorax. CT in patients with pneumothorax led to a correct diagnosis of this disease.

Merkel cell polyomavirus and Langerhans cell neoplasm

BACKGROUND

The relationship between various external agents such as pollen, food, and infectious agents and human sensitivity exists and is variable depending upon individual's health conditions. For example, we believe that the pathogenetic potential of the Merkel cell polyomavirus (MCPyV), the resident virus in skin, is variable and depends from the degree of individual's reactivity. MCPyV as well as Epstein-Barr virus, which are normally connected with humans under the form of subclinical infection, are thought to be involved at various degrees in several neoplastic and inflammatory diseases. In this review, we cover two types of Langerhans cell neoplasms, the Langerhans cell sarcoma (LCS) and Langerhans cell histiocytosis (LCH), represented as either neoplastic or inflammatory diseases caused by MCPyV.

METHODS

We meta-analyzed both our previous analyses, composed of quantitative PCR for MCPyV-DNA, proteomics, immunohistochemistry which construct IL-17 endocrine model and interleukin-1 (IL-1) activation loop model, and other groups' data.

RESULTS

We have shown that there were subgroups associated with the MCPyV as a causal agent in these two different neoplasms. Comparatively, LCS, distinct from the LCH, is a neoplastic lesion (or sarcoma) without presence of inflammatory granuloma frequently observed in the elderly. LCH is a proliferative disease of Langerhans-like abnormal cells which carry mutations of genes involved in the RAS/MAPK signaling pathway. We found that MCPyV may be involved in the development of LCH.

CONCLUSION

We hypothesized that a subgroup of LCS developed according the same mechanism involved in Merkel cell carcinoma pathogenesis. We proposed LCH developed from an inflammatory process that was sustained due to gene mutations. We hypothesized that MCPyV infection triggered an IL-1 activation loop that lies beneath the pathogenesis of LCH and propose a new triple-factor model.

Spontaneous pneumothorax in diffuse cystic lung diseases

PURPOSE OF REVIEW

Diffuse cystic lung diseases (DCLDs) are a heterogeneous group of disorders with varying pathophysiologic mechanisms that are characterized by the presence of air-filled lung cysts. These cysts are prone to rupture, leading to the development of recurrent spontaneous pneumothoraces. In this article, we review the epidemiology, clinical features, and management DCLD-associated spontaneous pneumothorax, with a focus on lymphangioleiomyomatosis, Birt-Hogg-Dubé syndrome, and pulmonary Langerhans cell histiocytosis.

RECENT FINDINGS

DCLDs are responsible for approximately 10% of apparent primary spontaneous pneumothoraces. Computed tomography screening for DCLDs (Birt-Hogg-Dubé syndrome, lymphangioleiomyomatosis, and pulmonary Langerhans cell histiocytosis) following the first spontaneous pneumothorax has recently been shown to be cost-effective and can help facilitate early diagnosis of the underlying disorders. Patients with DCLD-associated spontaneous pneumothorax have a very high rate of recurrence, and thus pleurodesis should be considered following the first episode of spontaneous pneumothorax in these patients, rather than waiting for a recurrent episode. Prior pleurodesis is not a contraindication to future lung transplant.

SUMMARY

Although DCLDs are uncommon, spontaneous pneumothorax is often the sentinel event that provides an opportunity for diagnosis. By understanding the burden and implications of pneumothoraces in DCLDs, clinicians can facilitate early diagnosis and appropriate management of the underlying disorders.

Ninety-year-old man with hypereosinophilia, lymphadenopathies and pruritus

We report a case of a 90-year-old man with hypereosinophilia, lymphadenopathies and skin lesions, namely lichenification and pruritus. An aetiological investigation was performed, and a bone marrow (BM) biopsy and aspirate showed a hypercellular marrow with hypereosinophilia without dysmorphia or abnormal elements, and the BM and inguinal node's immunophenotyping denied any presence of abnormal lymphoid cell population. The inguinal node biopsy revealed a multinodular proliferation of large cells S100 and CD1a⁺, and a diagnosis of Langerhans cell histiocytosis was made. The hypereosinophilia and skin lesions were managed with corticotherapy with substantial improvement of cutaneous lesions and lymphadenopathies and normalisation of eosinophil count. Finally, to define if it is a single or multisystem disease, a skin biopsy will be necessary.

[Chronic cough, pleuritic chest pain, and night sweats in a 45‑year-old female smoker]

A 45-year-old woman presented with chronic cough, pleuritic chest pain, and night sweat. High-resolution computed tomography revealed multiple bilateral nodular lesions in a centrilobular distribution, primarily located in the upper and mid lung zones with relative sparing of the lung bases. No lymphadenopathy or pleural effusions were detected. Histological analysis confirmed the suspected diagnosis of pulmonary Langerhans cell histiocytosis. After smoking cessation the patient recovered completely.

Diagnostic Approach to Advanced Fibrotic Interstitial Lung Disease: Bringing Together Clinical, Radiologic, and Histologic Clues

Context.—

Idiopathic pulmonary fibrosis (IPF) is a distinctive clinicopathologic entity and the most common form of progressive diffuse lung scarring in older adults. Idiopathic pulmonary fibrosis manifests histopathologically as the usual interstitial pneumonia pattern. The usual interstitial pneumonia pattern is distinguished by geographically and temporally heterogeneous fibrosis that is peripherally accentuated, often with honeycombing and traction bronchiectasis. Idiopathic pulmonary fibrosis is not the only disease that leads to end-stage lung fibrosis, however, and several other entities may also cause advanced fibrosis. Surgical lung biopsies often present a diagnostic dilemma when they show clear evidence of advanced fibrosis, but the clinical, imaging, and/or histopathologic subcharacteristics suggest something other than IPF.

Objective.—

To address this dilemma, we review several other fibrotic lung diseases, including connective tissue disease–associated interstitial lung disease, chronic hypersensitivity pneumonitis, advanced pulmonary Langerhans cell histiocytosis, end-stage pulmonary sarcoidosis, Erdheim-Chester disease, Hermansky-Pudlak syndrome, and others, detailing their clinical, radiologic, and histopathologic attributes and emphasizing similarities to and differences from IPF.

Data Sources.—

Data sources comprised published peer-reviewed literature and personal experience of the authors.

Conclusions.—

Often, clues in the lung biopsy may offer the first suggestion of a fibrotic lung disease other than IPF, and accurate classification is important for prognosis, treatment, and the development of future therapies.

Interstitial lung disease related to smoking: imaging considerations

PURPOSE OF REVIEW

To discuss the imaging of interstitial lung disease believed to be caused by smoking.

RECENT FINDINGS

It is increasingly clear that smoking is associated with a variety of patterns of interstitial lung disease. The radiologic features of interstitial lung disease caused by smoking cigarettes are variable and may be nonspecific.

SUMMARY

It is now accepted that cigarette smoking can cause lung diseases other than lung cancer, chronic bronchitis and emphysema. Indeed, the hypothesis that tobacco smoke can cause interstitial lung disease - and, specifically, pulmonary fibrosis - dates back to the 1960s. The list of interstitial lung disease, in which smoking is believed to have an etiologic role, includes Langerhans' cell histiocytosis, respiratory bronchiolitis/respiratory bronchiolitis-interstitial lung disease and desquamative interstitial pneumonia. More recently, there is emerging evidence which suggests that smoking may be associated with other patterns of pulmonary fibrosis (e.g. nonspecific interstitial pneumonia and smoking-related interstitial fibrosis). In the present review we discuss the imaging of the interstitial lung disease known to be caused by smoking; the typical appearances and some of the diagnostic difficulties are discussed.

Pulmonary Langerhans cell histiocytosis: radiologic resolution following cessation of second hand smoking

We present a 65-year-old male former smoker with past medical history of renal cell carcinoma. Surveillance chest CT scan showed numerous progressive bilateral upper lobe predominant nodular cystic densities. A Video Assisted Thoracoscopic Surgery lung biopsy was diagnostic of Pulmonary Langerhans Cell Histiocytosis. Further questioning of the patient revealed exposure to second hand smoke from his wife. A repeat chest CT scan 6 months following cessation of all smoking exposure showed near complete resolution of the nodular densities. Our case report highlights the importance of early identification of second hand smoke exposure. Timely elimination of the exposure led to near complete radiologic resolution.

Smoking-related interstitial lung disease

BACKGROUND

Smoking-related interstitial lung diseases (SR-ILDs) are a heterogeneous group of diseases with major clinical significance. Reliable epidemiological data are not yet available.

METHOD

Review of pertinent literature retrieved by a selective search in PubMed.

RESULTS

The available data on many aspects of SR-ILDs are sparse, but recent studies on the pathophysiology and targeted treatment of these conditions have revealed ways in which clinical outcomes can be improved. Highresolution computerized tomography should be used for differential diagnosis; lung biopsy is often unnecessary. Oncogenic mutations play a role in the pathogenesis of pulmonary Langerhans-cell histiocytosis (PLCH). In the future, cladribine and vemurafenib may be treatment options for PLCH. Desquamative interstitial pneumonia (DIP) may be difficult to distinguish from respiratorybronchiolitis-associated interstitial lung disease (RB-ILD); DIP is treated with steroids and sometimes with immune suppressants. In idiopathic pulmonary fibrosis (IPF), the antifibrotic drugs pirfenidone and nintedanib can delay disease progression. Smoking is also a risk factor for combined pulmonary fibrosis and emphysema (CPFE), rheumatoid-arthritis-associated interstitial lung disease (RA-ILD), pulmonary alveolar proteinosis (PAP), acute eosinophilic pneumonia (AEP), and diffuse alveolar hemorrhage (DAH) in Goodpasture syndrome.

CONCLUSION

In smokers with exertional dyspnea and/or a nonproductive cough, SR-ILDs must be considered in the differential diagnosis. If an SR-ILD is suspected, the patient should be referred to a pulmonary specialist. Early treatment and smoking cessation can improve clinical outcomes, particularly in the acute and chronically progressive types of SR-ILD.

Pulmonary Langerhans Cell Histiocytosis-associated Pulmonary Hypertension Showing a Drastic Improvement Following Smoking Cessation

Pulmonary Langerhans cell histiocytosis (PLCH) is a rare, smoking-related, interstitial lung disease, and pulmonary hypertension (PH) is associated with mortality. We herein report a case of PLCH complicated by severe PH and respiratory impairment. After developing PH, the patient displayed a cystic pattern on chest high-resolution computed tomography (HRCT). This, in turn, corresponded with the scarring stage of PLCH. However, the patient's PH and respiratory impairment improve dramatically following smoking cessation. PLCH patients with a cystic pattern on chest HRCT may still be able to improve their PH and respiratory impairment when they are able to quit smoking.

Pulmonary Langerhans Cell Histiocytosis in an Adult Male Presenting with Central Diabetes Insipidus and Diabetes Mellitus: A Case Report

Pulmonary Langerhans cell histiocytosis is an uncommon diffuse cystic lung disease in adults. In rare cases, it can involve extrapulmonary organs and lead to endocrine abnormalities such as central diabetes insipidus. A 42-year-old man presented with polyphagia and polydipsia, as well as a dry cough and dyspnea on exertion. Magnetic resonance imaging of the hypothalamic-pituitary system failed to show the posterior pituitary, which is a typical finding in patients with central diabetes insipidus. This condition was confirmed by a water deprivation test, and the patient was also found to have type 2 diabetes mellitus. Computed tomographic scanning of the lungs revealed multiple, irregularly shaped cystic lesions and small nodules bilaterally, with sparing of the costophrenic angles. Lung biopsy through video-assisted thoracoscopic surgery revealed pulmonary Langerhans cell histiocytosis. On a follow-up visit, only 1 year after the patient had quit smoking, clinical and radiological improvement was significant. Here, we report an uncommon case of pulmonary Langerhans cell histiocytosis that simultaneously presented with diabetes insipidus and diabetes mellitus.

Diffuse Cystic Lung Disease. Part I

The diffuse cystic lung diseases (DCLDs) are a group of pathophysiologically heterogenous processes that are characterized by the presence of multiple spherical or irregularly shaped, thin-walled, air-filled spaces within the pulmonary parenchyma. Although the mechanisms of cyst formation remain incompletely defined for all DCLDs, in most cases lung remodeling associated with inflammatory or infiltrative processes results in displacement, destruction, or replacement of alveolar septa, distal airways, and small vessels within the secondary lobules of the lung. The DCLDs can be broadly classified according to underlying etiology as those caused by low-grade or high-grade metastasizing neoplasms, polyclonal or monoclonal lymphoproliferative disorders, infections, interstitial lung diseases, smoking, and congenital or developmental defects. In the first of a two-part series, we present an overview of the cystic lung diseases caused by neoplasms, infections, smoking-related diseases, and interstitial lung diseases, with a focus on lymphangioleiomyomatosis and pulmonary Langerhans cell histiocytosis.

Pulmonary Langerhans cell histiocytosis: a comprehensive analysis of 40 patients and literature review

BACKGROUND

Pulmonary Langerhans cell histiocytosis (PLCH) is a rare interstitial disease affecting primarily young adult smokers. In order to highlight the clinical features of the disease, we conducted a retrospective analysis on clinical data of PLCH patients followed at our center; moreover, we reviewed the current literature on PLCH.

METHOD AND RESULTS

Between January 2004 and July 2014, 40 patients with PLCH were evaluated at our Division. The average patients' age was 40 (± 14) years, and 22 of them were females. Diagnosis was based on search of CD1a+ cells in the bronchoalveolar lavage (10 patients), lung biopsy (8 patients), or cystic bone lesion's biopsy (2 patients); in 12 patients, diagnosis was achieved on the basis of the clinical-radiological data. The principal manifestation of PLCH was the presence of cysts involving upper lung zones with costophrenic sparing on chest CT scan (in 25 patients); micronodular pattern in the middle-upper zone and combination of the two radiological patterns were less frequently observed (in 9 and 6 patients, respectively). Pulmonary hypertension was found in 4 patients. Extra pulmonary manifestations were diabetes insipidus, bone lesions, and skin involvement (in 5, 7, and 1 patient, respectively). For 25 patients, smoking cessation was the only required therapy. Treatments with low dose of prednisolone, vinblastine and prednisolone, or 6-mercaptopurin were reserved for patients with major pulmonary or extra-pulmonary involvement (for 11, 4, and 5 patients, respectively). In conclusion, PLCH is a rare, multi-systemic disease; early diagnosis, accurate staging and smoking cessation are considered critical in PLCH management.

[Pulmonary manifestations of Langerhans cell histiocytosis]

Pulmonary Langerhans cell histiocytosis is a rare diffuse cystic interstitial pneumonia of unknown etiology that occurs selectively in young smokers of both genders. The multicenter studies conducted by the reference center have better defined the short and medium terms natural history of the disease and the clinical management of patients. A substantial proportion of patients experience a dramatic decline in their lung function soon after diagnosis. Importantly, smoking cessation is associated with a decreased risk of subsequent deterioration. Cladribine, a purine analogue, chemotherapy may dramatically improve lung function in patients with progressive pulmonary Langerhans cell histiocytosis, but this treatment should be used only in the setting of clinical research. Specific pulmonary hypertension therapies (anti-endothelin receptors, inhibitors of phosphodiesterases) may be used with caution in specialized centres for patients with severe pulmonary hypertension, and seem to be well tolerated. The recent identification of the V600E mutation of the BRAF oncogene in approximately half of the Langerhans cell histiocytosis lesions, including pulmonary granulomas, represents an important step forward in the understanding of the pathogenesis of Langerhans cell histiocytosis. Potentially it opens the way to targeted therapies.

The natural history of adult pulmonary Langerhans cell histiocytosis: a prospective multicentre study

BACKGROUND

The natural history of pulmonary Langerhans cell histiocytosis (PLCH) has been unclear due to the absence of prospective studies. The rate of patients who experience an early progression of their disease is unknown. Additionally, conflicting effects of smoking cessation on the outcome of PLCH have been reported.

METHODS

In this prospective, multicentre study, 58 consecutive patients with newly diagnosed PLCH were comprehensively evaluated over a two-year period. Our objectives were to estimate the incidence of early progression of the disease and to evaluate the impact of smoking status on lung function outcomes. Lung function deterioration was defined as a decrease of at least 15% in FEV1 and/or FVC and/or DLCO, compared with baseline values. At each visit, smoking status was recorded based on the patients' self-reports and urinary cotinine measurements that were blinded for the patients. The cumulative incidence of lung function outcomes over time was estimated using the non-parametric Kaplan-Meier method. Multivariate Cox models with time-dependent covariates were used to calculate the hazards ratios of the lung function deterioration associated with smoking status with adjustment for potential confounders.

RESULTS

The cumulative incidence of lung function deterioration at 24 months was 38% (22% for FEV1 and DLCO, and 9% for FVC). In the multivariate analysis, smoking status and PaO2 at inclusion were the only factors associated with the risk of lung function deterioration. The patients' smoking statuses markedly changed over time. Only 20% of the patients quit using tobacco for the entire study period. Nevertheless, being a non-smoker was associated with a decreased risk of subsequent lung function deterioration, even after adjustment for baseline predictive factors. By serial lung computed tomography, the extent of cystic lesions increased in only 11% of patients.

CONCLUSIONS

Serial lung function evaluation on a three- to six-month basis is essential for the follow-up of patients with recently diagnosed PLCH to identify those who experience an early progression of their disease. These patients are highly addicted to tobacco, and robust efforts should be undertaken to include them in smoking cessation programs.

TRIAL REGISTRATION

ClinicalTrials.gov: No: NCT01225601 .

Rare interstitial lung disease: Pulmonary Langerhans Cell Histiocytosis in a young non smoking Indian female

Adult Pulmonary Langerhans Cell Histiocytosis (PLCH) is a rare interstitial lung disease which occurs almost exclusively in smokers. A marked male predominance was initially reported, but recent studies show both men and women are equally affected due to the increasing smoking habits in women. The natural history is variable with 25% of patients having asymptomatic disease while 10-20% progress rapidly to respiratory insufficiency and death. The diagnosis is not easily recognized by clinicians or pathologists. Awareness of the clinical presentation and classical HRCT findings helps in early diagnosis and management of this disease. We report a rare case of severe PLCH in a young non smoking female with a short history who progressed rapidly to respiratory failure and died.

Interleukin-1 loop model for pathogenesis of Langerhans cell histiocytosis

We propose Langerhans cell histiocytosis (LCH) is an inflammatory process that is prolonged by mutations. We hypothesize that Merkel cell polyomavirus (MCPyV) infection triggers an interleukin-1 (IL-1) activation loop that underlies the pathogenesis of LCH. Langerhans cells (LCs) are antigen presenting cells in the skin. When LCs encounter exogenous antigens, they migrate from the epidermis into draining lymphoid tissues to initiate T-cell activity. It has been proposed that LC migration-related factors, including E-cadherin, matrix metalloproteinase, and Notch ligand induce LCH activity. We found that the tyrosine phosphatase SHP-1, which binds IL-1 receptor-associated kinase 1, is expressed at a significantly higher level in LCH affecting multiple organ systems (MS-LCH) than in LCH affecting a single organ system (SS-LCH). IL-1 stimulates T helper 17 cells and their signature cytokine IL-17 had been a matter of controversy. We detected higher levels of IL-17A receptor expression in MS-LCH than in SS-LCH and proposed an IL-17 endocrine model that could settle the controversy. IL-1 is the first cytokine secreted in response to sensitizers and promotes LC migration from sentinel tissues. Myeloid differentiation primary response 88 (MyD88), downstream of the IL-1 receptor, has functions in both RAS signaling and inflammation, leading to human cell transformation. In 2010, an activating mutation in the B-rapidly accelerated fibrosarcoma gene (BRAF) V600E was found in LCH. This BRAF mutation induces phosphorylation of the extracellular signal-regulated kinase (ERK) that may play an important role with MyD88 in LCH pathogenesis. However, phosphorylated ERK (pERK) is rapidly dephosphorylated by dual specificity phosphatase 6 (DUSP6), and limited proliferation is predicted in BRAF mutant cells. MyD88 binds pERK via its D-domain, thereby preventing pERK–DUSP6 interaction and maintaining ERK in an active, phosphorylated state. We detected MCPyV-DNA in the peripheral blood cells of two out of three patients with LCH in high-risk organs but not in those of patients with LCH in non–high-risk organs (0/12; P = .029). MCPyV infection can trigger precursor LCH cells with BRAF mutation to produce IL-1; the IL-1 loop is amplified in all LCH subclasses. Our model indicates both BRAF mutation and IL-1 loop regulation as potential therapeutic targets.

Pulmonary Langerhans Cell Histiocytosis with Lytic Bone Involvement in an Adult Smoker: Regression following Smoking Cessation

Langerhans cell histiocytosis (LCH) is a rare myeloid neoplasm characterized by the proliferation and dissemination of histiocytes. These in turn may cause symptoms ranging from isolated, infiltrative lesions to severe multisystem disease. Pulmonary Langerhans cell histiocytosis (PLCH) presents as a localized polyclonal proliferation of Langerhans cells in the lungs causing bilateral cysts and fibrosis. In adults, this rare condition is considered a reactive process associated with cigarette smoking. Recently, clonal proliferation has been reported with the presence of BRAF V600E oncogenic mutation in a subset of PLCH patients. Spontaneous resolution was described; however, based on case series, smoking cessation remains the most effective way to achieve complete remission and prevent long term complications related to tobacco. Herein, we report the case of an adult woman with biopsy-proven PLCH presenting with thoracic (T8) vertebral bone destruction. Both the lung and the bone diseases regressed following smoking cessation, representing a rare case of synchronous disseminated PCLH with bone localization. This observation underscores the contribution of cigarette smoking as a systemic trigger of both pulmonary and extrapulmonary bone lesions. A review of similar cases in the literature is also presented.

Effectiveness of cladribine therapy in patients with pulmonary Langerhans cell histiocytosis

Background

Pulmonary Langerhans cell histiocytosis (PLCH) is a rare disorder characterised by granulomatous proliferation of CD1a-positive histiocytes forming granulomas within lung parenchyma, in strong association with tobacco smoking, and which may result in chronic respiratory failure. Smoking cessation is considered to be critical in management, but has variable effects on outcome. No drug therapy has been validated. Cladribine (chlorodeoxyadenosine, 2-CDA) down-regulates histiocyte proliferation and has been successful in curbing multi-system Langerhans cell histiocytosis and isolated PLCH.

Methods and patients

We retrospectively studied 5 patients (aged 37–55 years, 3 females) with PLCH who received 3 to 4 courses of cladribine therapy as a single agent (0.1 mg/kg per day for 5 consecutive days at monthly intervals). One patient was treated twice because of relapse at 1 year. Progressive pulmonary disease with obstructive ventilatory pattern despite smoking cessation and/or corticosteroid therapy were indications for treatment. Patients were administered oral trimethoprim/sulfamethoxazole and valaciclovir to prevent opportunistic infections. They gave written consent to receive off-label cladribine in the absence of validated treatment.

Results

Functional class dyspnea improved with cladribine therapy in 4 out of 5 cases, and forced expiratory volume in 1 second (FEV1) increased in all cases by a mean of 387 ml (100–920 ml), contrasting with a steady decline prior to treatment. Chest high-resolution computed tomography (HRCT) features improved with cladribine therapy in 4 patients. Hemodynamic improvement was observed in 1 patient with pre-capillary pulmonary hypertension. The results suggested a greater treatment effect in subjects with nodular lung lesions and/or thick-walled cysts on chest HRCT, with diffuse hypermetabolism of lung lesions on positron emission tomography (PET)-scan, and with progressive disease despite smoking cessation. Infectious pneumonia developed in 1 patient, with later grade 4 neutrocytopenia but without infection.

Discussion

Data interpretation was limited by the retrospective, uncontrolled study design and small sample size.

Conclusion

Cladribine as a single agent may be effective therapy in patients with progressive PLCH.

Establishment of a Langerhans cell histiocytosis lesion cell line with dermal dendritic cell characteristics

A cell line named PRU-1, derived from a Langerhans cell (LC) histiocytosis (LCH) skull lesion of a 7-year-old boy, was established and characterized. PRU-1 is an adherent spindle-shaped cell line that shows no Birbeck granules on electron microscopy. Flow cytometric analysis of cells collected from the early seventh passage showed no LC phenotypes of CD1a and S100 protein. Immunostaining of PRU-1 cells also revealed no expression of LC markers but showed expression of CD11c, CD54 (ICAM-1) and CD68, which was also observed in some peripherally located cells of the original LCH lesion. The PRU-1 cells stained positive for factor XIIIa and negative for CD34, suggesting a dermal dendritic cell phenotype. Cytogenetic analyses revealed abnormalities such as 39,XY,-2,-4,-8,-12,-12,-14,add(18)(q21),20,+mar and 44,XY,-11,-14,add(18)(q21). TCRγ rearrangement in the PRU-1 cells was not amplified by PCR. Tumorigenicity was not proven by xenografting into SCID mice. A conditioned medium from PRU-1 culture induced the proliferation of peripheral blood lymphocytes as well as the activation of monocytes from a healthy donor into CD1a-positive LC-like cells. Because the phenotypic characteristics of PRU-1 differed from those of CD1a-positive abnormal LC-like cells (LCH cells), it was likely that the PRU-1 cells were derived from peripherally located cells of the LCH lesion rather than LCH cells. LCH has been regarded as a type of granulomatous neoplasm with several intermingled inflammatory cells and influenced by stimuli such as Merkel cell polyomavirus (MCPyV) infection or cigarette smoking. However, in the PRU-1 cells, MCPyV-DNA was not detected by PCR. Stromal cell-like PRU-1 cells are likely to produce some growth or differentiation factors, which may play important roles in LCH lesion formation, cell maintenance and LC-like cell induction.

Unusual causes of pneumothorax

Pneumothorax is divided to primary and secondary. It is a situation that requires immediate treatment, otherwise it could have severe health consequences. Pneumothorax can be treated either by thoracic surgeons, or pulmonary physicians. In our current work, we will focus on unusual cases of pneumothorax. We will provide the etiology and treatment for each case, also a discussion will be made for each situation.

Complete pathological resolution of pulmonary Langerhans cell histiocytosis

Cigarette smoking is a major risk factor for pulmonary Langerhans cell histiocytosis (pLCH) and lung cancer. Resolution of pLCH may occur spontaneously, after smoking cessation or other interventions. However, despite clinicoradiological resolution, residual pulmonary Langerhans cells may be present and may lead to recurrent disease. We report the first case of pLCH with a complete histological resolution.

[Interstitial lung diseases (ILD) in smokers: spectrum in high resolution computed tomography (HRCT)]

Smoking is a known risk factor for the development of various interstitial lung diseases, e.g. respiratory bronchiolitis, respiratory bronchiolitis-associated interstitial lung disease, desquamative interstitial pneumonia, and pulmonary Langerhans cell histiocytosis. These disorders frequently present with overlapping clinical pathological features and in addition may coexist within the same patient. In the clinical routine the differential diagnosis may be challenging or even impossible; therefore, smoking-related lung diseases are considered as part of the same disease spectrum representing different degrees of lung parenchymal damage secondary to cigarette smoke exposure. The role of cigarette smoking in the development of pulmonary fibrosis is complex and subject to intense investigation. It encompasses a subset of patients with nonspecific interstitial pneumonia where cigarette smoking may have played a causative role as well as patients with combined pulmonary fibrosis and emphysema (CPFE) as a novel entity with clearly defined clinical radiological features.

Diffuse cystic lung diseases

Diffuse cystic lung diseases are uncommon but can present a diagnostic challenge because increasing number of diseases have been associated with this presentation. Cyst in the lung is defined as a round parenchymal lucency with a well-defined thin wall (< 2 mm thickness). Focal or multifocal cystic lesions include blebs, bullae, pneumatoceles, congenital cystic lesions, traumatic lesions, and several infectious processes such as coccidioidomycosis, Pneumocystis jiroveci pneumonia, and hydatid disease. "Diffuse" distribution in the lung implies involvement of all lobes. Diffuse lung involvement with cystic lesions can be seen in pulmonary lymphangioleiomyomatosis, pulmonary Langerhans' cell histiocytosis, lymphoid interstitial pneumonia, Birt-Hogg-Dubé syndrome, amyloidosis, light chain deposition disease, honeycomb lung associated with advanced fibrosis, and several other rare causes including metastatic disease. High-resolution computed tomography of the chest helps define morphologic features of the lung lesions as well as their distribution and associated features such as intrathoracic lymphadenopathy. Correlating the tempo of the disease process and clinical context with chest imaging findings serve as important clues to defining the underlying nature of the cystic lung disease and guide diagnostic evaluation as well as management.

Intriguing bronchoalveolar lavage proteome in a case of pulmonary langerhans cell histiocytosis

Background:

Pulmonary Langerhans cell histiocytosis (PLCH) is a rare interstitial lung disease associated with tobacco smoke exposure. New insights into its pathogenesis and how it differs from that of chronic obstructive pulmonary disease (COPD) may be provided by proteomic studies on bronchoalveolar lavage fluid (BALF).

Case Report:

We present the BALF proteome in a biopsy-proven case of PLCH and compare it with typical proteomes of COPD and of the healthy lung. The BALF proteins were separated by two-dimensional gel electrophoresis (2-DE) and the protein patterns were analyzed with a computerized 2-DE imaging system. As compared to the healthy subject and the COPD case, the PLCH case showed a strikingly different 2-DE pattern. There was much more IgG (heavy chain) and orosomucoid, and less α₁-antitrypsin, surfactant protein-A, haptoglobin, cystatin-S, Clara cell protein 10, transthyretin and gelsolin. Moreover, no apolipoprotein-A1, pro-apolipoprotein-A1, amyloid P, calgranulin A, or calgranulin B was detected at all.

Conclusions:

This case of PLCH presents with an extreme BALF proteome lacking significant amounts of protective and anti-inflammatory proteins. Thus, the intriguing BALF proteome opens up new lines of research into the pathophysiology of PLCH and how its pathogenesis differs from that in COPD.

IL-17A receptor expression differs between subclasses of Langerhans cell histiocytosis, which might settle the IL-17A controversy

Langerhans cell histiocytosis (LCH) is a lymphoproliferative disorder consisting of abnormal Langerhans cell-like cells and other lymphoid cells. LCH presents as either a multisystem LCH (LCH-MS) or a single-system LCH (LCH-SS). Currently, neither the pathogeneses nor the factors that define these disease subclasses have been elucidated. The interleukin (IL)-17A autocrine LCH model and IL-17A-targeted therapies have been proposed and have engendered much controversy. Those authors showed high serum IL-17A levels in LCH and argued that serum IL-17A-dependent fusion activities in vitro, rather than serum IL-17A levels, correlated with LCH severity (i.e. the IL-17A paradox). In contrast, others could not confirm the IL-17A autocrine model. So began the controversy on IL-17A, which still continues. We approached the IL-17A controversy and the IL-17A paradox from a new perspective in considering the expression levels of IL-17A receptor (IL-17RA). We detected higher levels of IL-17RA protein expression in LCH-MS (n = 10) as compared to LCH-SS (n = 9) (P = 0.041) by immunofluorescence. We reconfirmed these data by re-analyzing GSE16395 mRNA data. We found that serum levels of IL-17A were higher in LCH (n = 38) as compared to controls (n = 20) (P = 0.005) with no significant difference between LCH subclasses. We propose an IL-17A endocrine model and stress that changes in IL-17RA expression levels are important for defining LCH subclasses. We hypothesize that these IL-17RA data could clarify the IL-17A controversy and the IL-17A paradox. As a potential treatment of LCH-MS, we indicate the possibility of an IL-17RA-targeted therapy.

Pulmonary langerhans cell histiocytosis

Pulmonary Langerhans Cell Histiocytosis (PLCH) is a relatively uncommon lung disease that generally, but not invariably, occurs in cigarette smokers. The pathologic hallmark of PLCH is the accumulation of Langerhans and other inflammatory cells in small airways, resulting in the formation of nodular inflammatory lesions. While the overwhelming majority of patients are smokers, mechanisms by which smoking induces this disease are not known, but likely involve a combination of events resulting in enhanced recruitment and activation of Langerhans cells in small airways. Bronchiolar inflammation may be accompanied by variable lung interstitial and vascular involvement. While cellular inflammation is prominent in early disease, more advanced stages are characterized by cystic lung destruction, cicatricial scarring of airways, and pulmonary vascular remodeling. Pulmonary function is frequently abnormal at presentation. Imaging of the chest with high resolution chest CT scanning may show characteristic nodular and cystic abnormalities. Lung biopsy is necessary for a definitive diagnosis, although may not be required in instances were imaging findings are highly characteristic. There is no general consensus regarding the role of immunosuppressive therapy in smokers with PLCH. All smokers must be counseled on the importance of smoking cessation, which may result in regression of disease and obviate the need for systemic immunosuppressive therapy. The prognosis for most patients is relatively good, particularly if longitudinal lung function testing shows stability. Complications like pneumothoraces and secondary pulmonary hypertension may shorten life expectancy. Patients with progressive disease may require lung transplantation.

Smoking-related interstitial lung diseases

Cigarette smoke, a toxic collection of thousands of chemicals generated from combustion of tobacco, is recognized as the primary causative agent of certain diffuse interstitial and bronchiolar lung diseases. Most patients afflicted with these disorders are cigarette smokers, and smoking cessation has been shown to be capable of inducing disease remission and should occupy a pivotal role in the management of all smokers with these diffuse lung diseases. The role of pharmacotherapy with corticosteroids or other immunomodulating agents is not well established but may be considered in patients with progressive forms of smoking-related interstitial lung diseases.

Smoking-related interstitial lung diseases

Cigarette smoke, a toxic collection of thousands of chemicals generated from combustion of tobacco, is recognized as the primary causative agent of certain diffuse interstitial and bronchiolar lung diseases. Most patients afflicted with these disorders are cigarette smokers, and smoking cessation has been shown to be capable of inducing disease remission and should occupy a pivotal role in the management of all smokers with these diffuse lung diseases. The role of pharmacotherapy with corticosteroids or other immunomodulating agents is not well established but may be considered in patients with progressive forms of smoking-related interstitial lung diseases.