Organising pneumonia

New insights into imaging of pulmonary metastases from extra-thoracic neoplasms

The lung is one of the most common sites of metastases from extra-thoracic neoplasms. Lung metastases can show heterogeneous imaging appearance, thus mimicking a wide range of lung diseases, from benign lesions to primary lung cancer. The proper interpretation of pulmonary findings is crucial for prognostic assessment and treatment planning, even to avoid unnecessary procedures and patient anxiety. For this purpose, computed tomography (CT) is one of the most used imaging modalities. In the last decades, cancer patients' population has steadily increased and, due to the widespread application of CT for staging and surveillance, the detection of pulmonary nodules has raised, making their characterization and management an urgent and mostly unsolved problem for both radiologists and clinicians. This review will highlight the pathways of dissemination of extra-thoracic tumours to the lungs and the heterogeneous CT imaging appearance of pulmonary metastases, providing useful clues to properly address the diagnosis. Furthermore, we will deal with the promising applications of radiomics in this field. Finally, a focus on the hot-topic of pulmonary nodule management in patients with extra-thoracic neoplasms (ETNs) will be discussed.

Management of the Diagnosis and Treatment of Pneumonia in an Aging Society

The diagnosis of pneumonia is based on respiratory and systemic symptoms, blood test findings, chest radiographic findings, and the condition of the patient. Physicians in aging or aged societies such as Japan carefully evaluate the comprehensive situation of each pneumonia patient with adequate evaluation and treatment according to "the Japanese Respiratory Society (JRS) guidelines for the management of pneumonia in adults in 2024." These guidelines categorize pneumonia into three types: community-acquired, nursing- and healthcare-associated, and hospital-acquired. The selection of treatment settings and empirical antimicrobials for pneumonia depends on pneumonia classification, severity, and risk factors for potential drug-resistant bacteria, as outlined in the JRS guidelines. This review concisely describes the historical evolution of the diagnosis and treatment of pneumonia in elderly societies, including aspiration pneumonia, from multiple perspectives. In addition, it explores the differential diagnoses when antimicrobial treatment for pneumonia is ineffective, highlighting key aspects through chest radiography and computed tomography.

Pulmonary Manifestations in Patients With Hematologic Malignancies: In Pursuit of an Accurate Diagnosis

Pulmonary involvement is common in patients with hematologic malignancies (HMs) and varies depending on the underlying condition, including lymphoproliferative disorders, acute leukemia, myelodysplastic syndrome, and allogeneic stem cell transplantation. Pulmonary complications are a frequent cause of morbidity and mortality in these patients, often resulting from the immunosuppressive effects of the disease or its treatment. The clinical manifestations of these complications are nonspecific, and their differential diagnosis is broad, encompassing both infectious and noninfectious causes. A thorough clinical assessment requires consideration of factors such as the patient's history, baseline immune status, treatment regimens, time since the last chemotherapy, and environmental exposures. Radiographic imaging, particularly high-resolution CT, plays a critical role in evaluating these complications, helping clinicians identify distinct patterns of pulmonary involvement. Therefore, a personalized diagnostic approach is essential, and multidisciplinary management is crucial for optimal patient care.

Secondary organizing pneumonia after infection

This editorial explores the clinical implications of organizing pneumonia (OP) secondary to pulmonary tuberculosis, as presented in a recent case report. OP is a rare condition characterized by inflammation in the alveoli, which spreads to alveolar ducts and terminal bronchioles, usually after lung injuries caused by infections or other factors. OP is classified into cryptogenic (idiopathic) and secondary forms, the latter arising after infections, connective tissue diseases, tumors, or treatments like drugs and radiotherapy. Secondary OP may be triggered by infections caused by bacteria, viruses, fungi, mycobacteria, or parasites. Key diagnostic features include subacute onset of nonspecific respiratory symptoms such as dry cough, chest pain, and exertional dyspnea. Imaging with computed tomography scans typically reveals three patterns: (1) Bilateral subpleural consolidation; (2) Nodular consolidation; and (3) A reticular pattern. Bronchoscopy with bronchoalveolar lavage helps exclude other causes. Standard treatment consists of corticosteroid therapy tapered over 6 months to 12 months. This editorial highlights clinical and diagnostic strategies to ensure timely and effective patient care.

Multifocal Pulmonary Opacities in an Elderly Smoker

Organizing pneumonia (OP) directly caused by ongoing cigarette smoking does not appear to have been previously described. Despite OP having pathophysiological features distinct from lung cancer, the two may be confused based on similar clinical, radiological, and histopathological findings. This distinction is further clouded by the dynamic nature of these diseases. Diagnostic accuracy can likely be improved with a multidisciplinary approach that involves input from several specialists and serial reevaluations as the disease evolves. We present a case of OP that was initially misdiagnosed as non-small-cell lung cancer and resolved with smoking cessation.

Corticosteroid Therapy Duration and Dosage According to the Timing of Treatment Initiation for Post-COVID-19 Organizing Pneumonia

COVID-19 can lead to pulmonary complications, including organizing pneumonia. Steroids are essential in treating post-COVID-19 organizing pneumonia. However, research on the clinical benefits of initiating steroid treatment early for this condition is limited. To investigate the steroid initiation time in its association with treatment duration and corticosteroid dose for treating post-COVID-19 organizing pneumonia, we analyzed the data of 91 patients with post-COVID-19 organizing pneumonia at Chonnam National University Hospital between October 2020 and December 2022. Patients were categorized into early and late groups based on time from COVID-19 diagnosis to steroid initiation time for organizing pneumonia. The mean time interval between COVID-19 infection and steroid initiation time for treating organizing pneumonia, was 18.4±8.6 days. Within the early treatment group (treatment initiated <18.4 days after COVID-19), which included 55 patients, the mean duration of steroid treatment was 43.1±18.3days. In contrast, the late treatment group (initiated ≥18.4 days after COVID-19), which consisted of 36 patients, had a longer mean duration of steroid treatment 59.1±22.6 days) (p<0.01). Regarding corticosteroid dosing, the early treatment group had an average dosage of 0.5±0.3 mg/kg/day, in contrast to the late group, which averaged 0.8±0.3 mg/kg/day (p<0.01). Regression analysis showed steroid initiation time significantly influenced treatment duration (β=0.80 , p<0.01) and dosage (β=0.03, p<0.01). The clinical benefits of early steroid treatment for post-COVID-19 organizing pneumonia may lie in its association with reduced steroid treatment duration and dosage.

Enhancing Organizing Pneumonia Diagnosis: A Novel Super-token Transformer Approach for Masson Body Segmentation

BACKGROUND/AIM

In this study, we introduce an innovative deep-learning model architecture aimed at enhancing the accuracy of detecting and classifying organizing pneumonia (OP), a condition characterized by the presence of Masson bodies within the alveolar spaces due to lung injury. The variable morphology of Masson bodies and their resemblance to adjacent pulmonary structures pose significant diagnostic challenges, necessitating a model capable of discerning subtle textural and structural differences. Our model incorporates a novel architecture that integrates advancements in three key areas: Semantic segmentation, texture analysis, and structural feature recognition.

MATERIALS AND METHODS

We employed a dataset of whole slide imaging from 20 patients, totaling 100 slides of OP, segmented into training, validation, and testing sets to reflect real-world application scenarios. Our approach utilizes a modified multi-head self-attention mechanism combined with ResUNet for semantic segmentation, enhanced by superpixel concepts. This method facilitates the generation of representative token features through iterative super-token blocks, creating high-resolution token maps that leverage local and high-level feature information for improved accuracy.

RESULTS

Benefiting from token features and distribution for enhanced texture alignment with fewer false-positives, the super-token transformer (STT) model achieved a mean intersection over union (mIOU) of 72.42%, with a sensitivity of 47.81%, specificity of 99.83%, positive predictive value of 64.03%, and negative predictive value of 99.94%, highlighting superior efficacy in Masson body segmentation in complex cross-tissue analyses.

CONCLUSION

Our team developed an iterative learning model based on the STT approach, emphasizing token features of super token, including texture and distribution, that enable enhanced alignment with the unique textures of Masson bodies to improve sensitivity and mIOU, The development of this STT model presents a significant advancement in the field of medical image analysis for OP that offers a promising avenue for improving diagnostic precision and patient outcomes in pulmonary pathology.

Case report: Suspected organizing pneumonia secondary to severe respiratory syncytial virus pneumonia in an elderly patient

Respiratory syncytial virus (RSV) usually causes acute respiratory tract infection in infants. In recent years, it has gradually become an important pathogen of lower respiratory tract infection in elderly people with an underlying disease. However, at present, the treatment of severe RSV pneumonia in adults is unclear, and organizing pneumonia (OP) after severe RSV infection has rarely been reported. We reported a 76-year-old man with multiple chronic heart and lung diseases who presented with fever, cough and progressive dyspnea. Finally, severe RSV pneumonia was diagnosed after his nasopharyngeal swabs and bronchoalveolar lavage metagenomic next-generation sequencing tests were positive for RSV. After combined treatment with oral ribavirin, intravenous immunoglobulin and corticosteroids, the patient's condition largely resolved, and he was discharged. However, when the corticosteroids were gradually tapered, the disease relapsed twice, and the patient experienced fever and aggravated dyspnea. Despite the lack of pathological evidence, we highly suspected organizing pneumonia secondary to severe RSV pneumonia based on the typical imaging manifestations and the clinical characteristics of a good response to corticosteroids. Finally, this patient was successfully treated with a course of corticosteroids and followed up for 14 months in total.

Organizing Pneumonia in a Case of Cold Agglutinin Disease with Pulmonary Thrombosis

Cold agglutinin disease is a subtype of autoimmune hemolytic anemia that occurs via the activation of specific anti-red blood cell antibodies (agglutinins) at low temperatures. Autoimmune hemolytic anemia has been reported to cause interstitial pneumonia; however, the underlying mechanism remains unclear. We herein report a 46-year-old man diagnosed with cold agglutinin disease complicated by pulmonary thrombosis and organizing pneumonia. Treatment with prednisolone improved the course of cold agglutinin disease and organizing pneumonia in a similar manner. To our knowledge, this is the first report of cold agglutinin associated with organizing pneumonia, suggesting a potential link between the two.

Imaging of the Spectrum of Acute Lung Injury

Organizing pneumonia, acute fibrinous and organizing pneumonia, and diffuse alveolar damage, represent multi-compartment patterns of lung injury. The initial region of injury in all remains the same and is centered on the fused basement membrane (BM) between the capillary endothelium and type I pneumocyte. Injury leads to cellular death, BM denudation, increased cellular permeability, and BM structural damage, which leads to exudation, organization, and attempts at repair. When acute lung injury does lead to fibrosis, in some instances it can lead to histologic and/or radiologic usual interstitial pneumonia or nonspecific interstital pneumonia patterns suggesting that lung injury is the primary mechanism for the development of fibrosis.

A Case of Chronic Pulmonary Aspergillosis due to Pulmonary Infarction, Mimicking Cryptogenic Organising Pneumonia

A patient initially treated with corticosteroids for cryptogenic organising pneumonia following pulmonary infarction, developed a worsening condition with progressive cavitary formations in both lower lung lobes. Contrast-enhanced chest computed tomography revealed a pulmonary embolism, and serum anti-Aspergillus IgG antibody analysis yielded a strong positive result. Consequently, the patient was diagnosed with pulmonary infarction with Aspergillus infection; organising pneumonia in surrounding areas reflected the repair process. Following treatment with anticoagulants and antifungal agents, the patient was successfully discharged. Hence, pulmonary infarction should be considered in cases of refractory lung lesions.

LEARNING POINTS

Pulmonary infarction should be considered in case of refractory lung lesions, even if the patient does not have the risk of embolism.Organising pneumonia should be assessed carefully because it may occur as a repair process of various lung diseases.

Secondary organizing pneumonia associated with protracted COVID: A case series

OBJECTIVES

Immunocompromised B-cell-depleted patients are at risk of developing protracted COVID-19, a clinical syndrome characterized by prolonged viral shedding and respiratory symptoms that can lead to hypoxemic pneumonia. Our aim is to describe this unusual condition and its treatment.

PATIENTS AND METHODS

This monocentric retrospective study reports six cases of severe organizing pneumonia that developed during the clinical course of protracted COVID-19.

RESULTS

All patients developed organizing pneumonia (OP) in the setting of protracted COVID. Clinical improvement was obtained after several treatment lines including specific antiviral agents and occurred simultaneously with control of the viral load.

CONCLUSION

As it was the most frequent presentation of protracted COVID-19 in our survey, we believe that this specific form of organizing pneumonia warrants increased awareness. Furthermore, specific antiviral therapy seems to control this condition.

Interstitial lung changes and persistent COVID-19 in a patient with follicular lymphoma: A case report

We herein report a case of interstitial lung changes in a patient with prolonged coronavirus disease 2019 (COVID-19) with follicular lymphoma receiving rituximab and bendamustine who recovered after treatment with a combination therapy consisting of corticosteroids and immunosuppressive agents. There is currently no treatment strategy for prolonged pneumonitis following COVID-19, which can be life-threatening for immunocompromised patients. Thus, further investigation is warranted.

Organizing Pneumonia Associated with Pneumocystis jirovecii in a Patient Receiving Dose-Dense Chemotherapy for Breast Cancer: A Case Report

In patients not infected by HIV, Pneumocystis jirovecii pneumonia (PCP) is characterized by rapid disease progression, difficulty in confirming the diagnosis, and poor prognosis. PCP has also been reported in immunocompromised patients receiving chemotherapy, most often for hematologic tumors, although some patients receiving treatment for breast cancer have been affected. Dose-dense chemotherapy (DDC) which is performed with shorter dosing intervals than standard chemotherapy and is now widely used in clinical practice. However, adverse events have been reported, including infections associated with decreased immune status. PCP infection is considerably more challenging to diagnose and treat than bacterial or viral infections. Furthermore, organizing pneumonia (OP), a pulmonary lesion of PCP, is infrequent and requires caution on the part of clinicians, as protozoan infections require different forms of treatment. Although we initially suspected bacterial, viral, and drug-induced pneumonia in our patient and started treatment with antibiotics, antifungals, and prednisolone, the final diagnosis was OP. The pulmonary lesion of PCP was treated with systemic corticosteroids, leading to recovery. There have been no similar reports of PCP during chemotherapy for malignant disease; however, the possibility of OP should be considered during chemotherapy. Herein, we report a case of PCP during preoperative DDC for advanced breast cancer.

Scleroderma Associated With Organising Pneumonia and Polyarthritis: A Report of a Rare Case

Cryptogenic organising pneumonia (COP) is a form of idiopathic diffuse interstitial lung disease (ILD) that develops in response to a variety of unknown irritants. An essential component of the development of organising pneumonia (OP) is damage to type II pneumocytes and the alveolar basement membrane. An autoimmune illness called systemic sclerosis (SSc) has a significant death rate from cardiopulmonary involvement such as pulmonary hypertension and ILD. Arthritis is an autoimmune disorder, in which the patients experience extra-articular symptoms such as ILD during the course of their disease, and COP frequently coexists with these conditions. It is exceedingly uncommon for OP to occur as the initial sign of arthritis, and its clinical characteristics are still unclear. Scleroderma and inflammatory polyarthritis related to COP are presented in this report.

Organizing pneumonia and COVID-19

Organizing pneumonia (OP) is an interstitial lung disease, and can be cryptogenic, if no cause is identified, or secondary to several conditions. COVID-19-induced persistent inflammation can be associated with interstitial lung disease. We present a review of literature of OP and COVID-19-induced OP with an illustrative case. A 38-year-old man was admitted with COVID-19 that required mechanical ventilation for 56 days. Initial chest computed tomography (CT) revealed diffuse bilateral ground-glass opacities in the lungs with consolidation areas involving 75 % of the parenchyma. After weaning from MV, the patient still required oxygen supplementation. A new chest CT scan also showed extensive diffuse areas of consolidation and ground-glass opacity. OP was hypothesized and 40 mg/day prednisone initiated and continued for six months with resolution of lung functional and image abnormalities. Organizing pneumonia should be included in the differential diagnosis of COVID-19 patients with respiratory symptoms after partial pulmonary recovery.

A case series of three patients with histologically proven post COVID-19 organizing pneumonia

Organizing pneumonia, a form of interstitial lung disease, may occur in patients who have recovered from COVID-19. In this article, we report three cases of post COVID-19 organizing pneumonia, proven histologically with transbronchial biopsies showing fibroblastic plugs in the alveolar spaces. Our patients received a range of 86-166 days of continuous corticosteroid therapy and all of them made excellent recovery.

Delayed organising pneumonia in an immunocompromised host after a mild COVID-19 infection

Organising pneumonia after a mild COVID-19 infection has been increasingly reported and poses a diagnostic challenge to physicians especially in immunocompromised patients. We report a patient with a background of lymphoma in remission on rituximab who presented with prolonged and persistent fever after recovering from a mild COVID-19 infection. The initial workup showed bilateral lower zone lung consolidation; however, the infective and autoimmune workup were unremarkable. Subsequently, a bronchoscopy with transbronchial lung biopsy confirmed the diagnosis of organising pneumonia. A tapering glucocorticoid regimen was commenced with prompt resolution of the patient's clinical symptoms, and subsequent resolution of biochemical markers and radiological lung changes 3 months later. This case highlights the importance of early recognition of the diagnosis of organising pneumonia in immunocompromised populations after a mild COVID-19 infection as it shows promising response to glucocorticoid therapy.

Corticosteroid outcome may be dependent of duration of use in severe COVID-19

BACKGROUND/AIMS

For patients hospitalized with coronavirus disease 2019 (COVID-19) who require supplemental oxygen, the evidence of the optimal duration of corticosteroid is limited. This study aims to identify whether long-term use of corticosteroids is associated with decreased mortality.

METHODS

Between February 10, 2020 and October 31, 2021, we analyzed consecutive hospitalized patients with COVID-19 with severe hypoxemia. The patients were divided into short-term (≤ 14 days) and long-term (> 14 days) corticosteroid users. The primary outcome was 60-day mortality. We performed propensity score (PS) analysis to mitigate the effect of confounders and conducted Kaplan-Meier curve analysis.

RESULTS

There were 141 (52%) short-term users and 130 (48%) long-term corticosteroid users. The median age was 68 years and the median PaO2/FiO2 at admission was 158. Of the patients, 40.6% required high-flow nasal cannula, 48.3% required mechanical ventilation, and 11.1% required extracorporeal membrane oxygenation. The overall 60-day mortality rate was 23.2%, and that of patients with hospital-acquired pneumonia (HAP) was 22.9%. The Kaplan-Meier curve for 60- day survival in the PS-matched cohort showed that corticosteroid for > 14 days was associated with decreased mortality (p = 0.0033). There were no significant differences in bacteremia and HAP between the groups. An adjusted odds ratio for the risk of 60-day mortality in short-term users was 5.53 (95% confidence interval, 1.90-18.26; p = 0.003).

CONCLUSION

For patients with severe COVID-19, long-term use of corticosteroids was associated with decreased mortality, with no increase in nosocomial complications. Corticosteroid use for > 14 days can benefit patients with severe COVID-19.

The relationship between organising pneumonia and invasive mould disease in patients with haematologic malignancy

BACKGROUND

Organising pneumonia (OP) is reported in patients with haematologic malignancy suspected of having invasive mould disease, yet little is known about this relationship.

OBJECTIVE

To investigate molecular evidence of invasive mould pneumonia in paraffin-embedded lung tissues from histologically diagnosed OP patients with suspected invasive mould pneumonia.

PATIENTS/METHODS

Patients with haematologic malignancy suspected to have invasive pulmonary mould disease who underwent lung biopsy at a tertiary hospital, Seoul, South Korea, between 2008 and 2020, were retrospectively reviewed. To find molecular evidence of fungal infection, PCR assay was used to detect Aspergillus- and Mucorales-specific DNA within OP lung tissue sections.

RESULTS

Forty-seven patients with suspected invasive mould pneumonia underwent lung biopsy and 15 (32%) were histologically diagnosed as OP without any evidence of fungal hyphae. Of these 15 patients, 3 (20%) received allogenic haematopoietic stem cell transplantation prior to developing OP. Before biopsy, 2 and 13 patients had probably and possible invasive mould disease, respectively. The median antifungal treatment length was 81 [8-114] days, and the median steroid treatment dosage was 0.35 mg/kg/day for 36 days (methylprednisolone equivalent doses), respectively. After biopsy, three patients with possible invasive mould infection revealed probable invasive pulmonary aspergillosis. From the 15 paraffin-embedded lung tissues, 6 (40%) exhibited positive PCR assay results for detecting Aspergillus- and Mucorales-specific DNA.

CONCLUSIONS

More than one third of OP cases in patients with suspected invasive mould pneumonia exhibited molecular evidence of invasive mould infection by fungus-specific PCR in lung tissues, likely associated with concurrent or prior fungal infection.

Organizing pneumonia following ocrelizumab use in a patient with multiple sclerosis: A case report

Ocrelizumab is an anti-CD20 monoclonal antibody used in the treatment of primary progressive and relapsing multiple sclerosis (MS). Although cases of organizing pneumonia have been reported in association with other antiCD20 agents such as rituximab, there is insufficient data in the literature on Ocrelizumab-associated lung involvement. Herein, we present a case of organizing pneumonia in a 37-year-old female patient with multiple sclerosis following Ocrelizumab use.

A review of organizing pneumonia

ABSTRACT

Organizing pneumonia is a clinical and pathological syndrome that describes a lung injury caused by an inflammatory reaction in the alveolar connective tissue. Classified as an interstitial lung disease, it can be secondary to infection, drug toxicity, connective tissue disorders, inhalation injuries (cocaine), organ transplant, or radiotherapy, and also can be idiopathic. Although organizing pneumonia is not a new phenomenon, it has been noted to be a complication of COVID-19, and should be considered in patients who have had COVID-19 and have atypical chest imaging, because treatment includes corticosteroids instead of antimicrobials.

Steroid exposure and outcome in COVID-19 pneumonia

Background

Corticosteroids are used to treat COVID-19 pneumonia. However, the optimal dose is unclear. This study describes the association between corticosteroid exposure with disease severity and outcome in COVID-19 pneumonia.

Methods

This is a single-centre retrospective, observational study including adult ICU patients who received systemic corticosteroids for COVID-19 pneumonia between March 2020 and March 2021. We recorded patient characteristics, disease severity, total steroid exposure, respiratory support and gas exchange data, and 90-day mortality.

Results

We included 362 patients. We allocated patients to groups with increasing disease severity according to the highest level of respiratory support that they received: high-flow nasal oxygen or continuous positive airway pressure (HFNO/CPAP) in 12.7%, invasive mechanical ventilation (IMV) in 61.6%, and extracorporeal membrane oxygenation (ECMO) in 25.7%. For these three groups, the median (inter-quartile range [IQR]) age was 61 (54-71) vs 58 (50-66) vs 46 (38-53) yr, respectively (P<0.001); median (IQR) APACHE (Acute Physiology and Chronic Health Evaluation) II scores were 12 (9-15) vs 14 (12-18) vs 15 (12-17), respectively (P=0.006); the median (IQR) lowest P a O 2 /FiO₂ ratio was 15.1 (11.8-21.7) vs 15.1 (10.7-22.2) vs 9.5 (7.9-10.9) kPa, respectively (P<0.001). Ninety-day mortality was 9% vs 27% vs 37% (P=0.002). Median (IQR) dexamethasone-equivalent exposure was 37 (24-62) vs 174 (86-504) vs 535 (257-1213) mg (P<0.001). 'Pulsed' steroids were administered to 26% of the IMV group and 48% of the ECMO group. Patients with higher disease severity who received pulse steroids had a higher 90-day mortality.

Conclusions

Corticosteroid exposure increased with the severity of COVID-19 pneumonia. Pulsed dose steroids were used more frequently in patients receiving greater respiratory support. Future studies should address patient selection and outcomes associated with pulsed dose steroids in patients with severe and deteriorating COVID-19 pneumonia.

Case of organising pneumonia in HIV infection

A man in his 50s presented to his doctor with a fever, sore throat, cough, dysgeusia and dyspnoea of several days' duration. Tests for HIV antigen, HIV antibody and HIV PCR were positive. He was referred to our hospital for initiation of antiretroviral therapy and bronchoscopy to clarify the cause of an abnormal lung shadow on chest CT. He was diagnosed with organising pneumonia, with concurrent HIV infection. His pulmonary lesions were remitted spontaneously, and he was administered a fixed-dose combination of tenofovir (50 mg), emtricitabine (200 mg) and bictegravir (25 mg) for HIV. This is a rare report of organising pneumonia with HIV infection. Physicians need to consider organising pneumonia when lung opacity is observed in a patient with HIV infection.

Algorithmic Approach to the Diagnosis of Organizing Pneumonia: A Correlation of Clinical, Radiologic, and Pathologic Features

Organizing pneumonia (OP), characterized histopathologically by patchy filling of alveoli and bronchioles by loose plugs of connective tissue, may be seen in a variety of conditions. These include but are not limited to after an infection, drug reactions, radiation therapy, and collagen vascular diseases. When a specific cause is responsible for this entity, it is referred to as "secondary OP." When an extensive search fails to reveal a cause, it is referred to as "cryptogenic OP" (previously called "bronchiolitis obliterans with OP"), which is a clinical, radiologic, and pathologic entity classified as an interstitial lung disease. The clinical presentation of OP often mimics that of other disorders, such as infection and cancer, which can result in a delay in diagnosis and inappropriate management of the underlying disease. The radiographic presentation of OP is polymorphous but often has subpleural consolidations with air bronchograms or solitary or multiple nodules, which can wax and wane. Diagnosis of OP sometimes requires histopathologic confirmation and exclusion of other possible causes. Treatment usually requires a prolonged steroid course, and disease relapse is common. The aim of this article is to summarize the clinical, radiographic, and histologic presentations of this disease and to provide a practical diagnostic algorithmic approach incorporating clinical history and characteristic imaging patterns.

Glucocorticoid therapy in respiratory illness: bench to bedside

Each year, hundreds of millions of individuals are affected by respiratory disease leading to approximately 4 million deaths. Most respiratory pathologies involve substantially dysregulated immune processes that either fail to resolve the underlying process or actively exacerbate the disease. Therefore, clinicians have long considered immune-modulating corticosteroids (CSs), particularly glucocorticoids (GCs), as a critical tool for management of a wide spectrum of respiratory conditions. However, the complex interplay between effectiveness, risks and side effects can lead to different results, depending on the disease in consideration. In this comprehensive review, we present a summary of the bench and the bedside evidence regarding GC treatment in a spectrum of respiratory illnesses. We first describe here the experimental evidence of GC effects in the distal airways and/or parenchyma, both in vitro and in disease-specific animal studies, then we evaluate the recent clinical evidence regarding GC treatment in over 20 respiratory pathologies. Overall, CS remain a critical tool in the management of respiratory illness, but their benefits are dependent on the underlying pathology and should be weighed against patient-specific risks.

What you need to know about: organising pneumonia

Organising pneumonia was first described in the context of respiratory infection, but over time has become established as its own entity. It is an area of diagnostic complexity because of the non-specific presenting symptoms and signs that can often mimic other respiratory pathology. Multidisciplinary review to correlate clinical, radiological and histopathological features can aid timely and effective diagnosis. This article discusses the epidemiology, aetiology, clinical, radiological and histopathological features, investigation and management of organising pneumonia.

Demystifying idiopathic interstitial pneumonia: time for more etiology-focused nomenclature in interstitial lung disease

INTRODUCTION

A major focus of interstitial lung disease (ILD) has centered on disorders termed idiopathic interstitial pneumonias (IIPs) which include, among others, idiopathic pulmonary fibrosis, idiopathic nonspecific interstitial pneumonia, cryptogenic organizing pneumonia, and respiratory bronchiolitis-interstitial lung disease.

AREAS COVERED

We review the radiologic and histologic patterns for the nine disorders classified by multidisciplinary approach as IIP, and describe the remarkable amount of published epidemiologic, translational, and molecular studies demonstrating their associations with numerous yet definitive environmental exposures, occupational exposures, pulmonary diseases, systemic diseases, medication toxicities, and genetic variants.

EXPERT OPINION

In the 21st century, these disorders termed IIPs are rarely idiopathic, but rather are well-described radiologic and histologic patterns of lung injury that are associated with a wide array of diverse etiologies. Accordingly, the idiopathic nomenclature is misleading and confusing, and may also promote a lack of inquisitiveness, suggesting the end rather than the beginning of a thorough diagnostic process to identify ILD etiology and initiate patient-centered management. A shift toward more etiology-focused nomenclature will be beneficial to all, including patients hoping for better life quality and disease outcome, general medicine and pulmonary physicians furthering their ILD knowledge, and expert ILD clinicians and researchers who are advancing the ILD field.

Characteristics and Follow-Up of Organizing Pneumonia Associated with Haematological Malignancies

Background

Organizing pneumonia (OP) is a secondary process in many diseases. Due to its low incidence and indistinct symptoms, there is limited information on OP associated with haematological malignancies. Therefore, the aim of this study was to discuss the characteristics and prognosis of OP associated with haematological malignancies.

Methods

We observed and analysed pathologically confirmed OP cases associated with haematological malignancies in a hospital record database and excluded cases of OP with known causes, including chemotherapy, radiotherapy, targeted therapy, transplantation and infection.

Results

There were five patients with OP underlying only haematological malignancies, including one case each of the following: myelodysplastic syndrome, acute myelogenous leukaemia, multiple myeloma, aplastic anaemia, and T cell lymphoma. Radiological findings did not show a distinct pattern, and two cases mimicked pulmonary aspergillosis with ground-glass opacity (GGO). The diagnosis of OP was confirmed by minimal invasive biopsy. Although all patients developed severe cases, steroids yielded favourable outcomes.

Conclusion

This study demonstrates that haematological malignancies may be a cause of OP and that minimal invasive biopsy may be an effective and safe method to confirm the diagnosis. Although OP associated with haematological malignancies may more frequently develop into severe cases, the OP lesions were steroid-responsive during follow-up.

Pulmonary Toxicities of Immunotherapy

Immune checkpoint inhibitors are a form of immunotherapy that are increasingly being used in a wide variety of cancers. Immune-related adverse events (irAEs) pose a major challenge in the treatment of cancer patients. Pneumonitis, the most common lung irAE, can cause significant disruptions in the treatment of cancer and may be life-threatening. The goal of this chapter is to instruct readers on the incidence and clinical manifestations of pneumonitis and to offer guidance in the evaluation and treatment of patients with pneumonitis.

Two cases of cryptogenic organizing pneumonia masquerading as tuberculosis (TB) in a TB endemic area

Before the era of COVID-19 pandemic, organizing pneumonia (OP) is often underdiagnosed while tuberculosis (TB) is overdiagnosed especially in an endemic area. We report two patients with cryptogenic OP mimicking TB. First, a 56-year-old lady with right upper lobe air space opacity and, second, a 37-year-old lady with left upper lobe cavitary lesion. They were treated empirically for pulmonary TB as they had chronic cough with typical chest imaging findings. As there were no improvements despite anti-TB and investigations for TB were negative, they underwent image-guided biopsy which confirmed OP. Both patients received 6 months of corticosteroids therapy and made complete recovery. These cases highlight the rare presentation of OP and serves as a reminder that patients tested negative for TB, despite typical history and chest imaging findings, warrant further investigations as many diseases may mimic TB and vice versa.

Side Effects of Oncologic Treatment in the Chest: Manifestations at FDG PET/CT

Fluorodeoxyglucose (FDG) PET/CT is a vital imaging technique used for staging, assessing treatment response, and restaging following completion of therapy in patients who are undergoing or have completed oncologic treatment. A variety of adverse effects from chemotherapy, targeted therapy, immunotherapy, and radiation therapy are commonly encountered in oncologic patients. It is important to be aware of the manifestations of these adverse effects seen on FDG PET/CT images to avoid misinterpreting these findings as disease progression. Furthermore, early identification of these complications is important, as it may significantly affect patient management and even lead to a change in treatment strategy. The authors focus on the FDG PET/CT manifestations of a broad spectrum of oncologic therapy-related adverse effects in the thorax, as well as some treatment-related changes that may potentially mimic malignancy. Online supplemental material is available for this article. ^©RSNA, 2021.

Idiopathic Interstitial Pneumonias and COVID-19 Pneumonia: Review of the Main Radiological Features and Differential Diagnosis

COVID-19 pneumonia represents a challenging health emergency, due to the disproportion between the high transmissibility, morbidity, and mortality of the virus and healthcare systems possibilities. Literature has mainly focused on COVID-19 pneumonia clinical-radiological diagnosis and therapy, and on the most common differential diagnoses, while few papers investigated rare COVID-19 pneumonia differential diagnoses or the overlapping of COVID-19 pneumonia on pre-existing lung pathologies. This article presents the main radiological characteristics of COVID-19 pneumonia and Idiopathic Interstitial Pneumonias (IIPs) to identify key radiological features for a differential diagnosis among IIPs, and between IIPs and COVID-19 pneumonia. COVID-19 pneumonia differential diagnosis with IIPs is challenging, since these entities may share common radiological findings as ground glass opacities, crazy paving patterns, and consolidations. Multidisciplinary discussion is crucial to reach a final and correct diagnosis. Radiologists have a pivotal role in identifying COVID-19 pneumonia patterns, reporting possible overlapping with long-lasting lung diseases, and suggesting potential differential diagnoses. An optimal evaluation of HRTC may help in containing the disease, in promoting better treatment for patients, and in providing an efficient allocation of human and economic resources.

Case of Severe Treatment-Resistant Cryptogenic Organizing Pneumonia

Cryptogenic organizing pneumonia is a rare interstitial lung disease with different onset of symptoms, which responds rapidly to glucocorticoid treatment. We present a case of cryptogenic organizing pneumonia which manifested as a progressive 3-year dyspnea that ultimately has led to acute respiratory failure. Moreover, treatment with prednisone for this patient exhibited slow onset of the effect.

Adjunctive corticosteroid treatment for organizing pneumonia in COVID-19 patients with persistent respiratory failure

Since the beginning of COVID-19 pandemic, clinical, radiological and histopathological features consistent with viral-induced organizing pneumonia (OP) have been reported as hallmark characteristics of the disease. Here, we describe the case of ten patients with severe COVID-19 pneumonia treated with methylprednisolone 1mg/kg for showing clinical and radiological features suggestive of OP at least 20 days after symptom onset and despite standard treatment for COVID-19.

Vancomycin-Induced Organizing Pneumonia: A Case Report and Literature Review

The long-term administration of vancomycin has increased; however, the pulmonary adverse reactions of long-term vancomycin treatment remain under-studied. A 75-year-old male patient with vertebral osteomyelitis receiving long-term vancomycin therapy developed a fever. High resolution computed tomography showed irregular ground glass opacity and consolidation in the right upper lung. The patient developed organizing pneumonia. This occurred without peripheral eosinophilia or adverse reactions in the skin and liver. The administration of vancomycin was discontinued. He recovered from organizing pneumonia after four weeks of steroid therapy. Solitary organizing pneumonia can develop during treatment with vancomycin. When pulmonary inflammation occurs and other causes of pneumonia are excluded, vancomycin therapy should be discontinued.

Persistent Post-COVID-19 Interstitial Lung Disease. An Observational Study of Corticosteroid Treatment

Rationale: The natural history of recovery from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) remains unknown. Because fibrosis with persistent physiological deficit is a previously described feature of patients recovering from similar coronaviruses, treatment represents an early opportunity to modify the disease course, potentially preventing irreversible impairment.Objectives: Determine the incidence of and describe the progression of persistent inflammatory interstitial lung disease (ILD) following SARS-CoV-2 when treated with prednisolone.Methods: A structured assessment protocol screened for sequelae of SARS-CoV-2 pneumonitis. Eight hundred thirty-seven patients were assessed by telephone 4 weeks after discharge. Those with ongoing symptoms had outpatient assessment at 6 weeks. Thirty patients diagnosed with persistent interstitial lung changes at a multidisciplinary team meeting were reviewed in the interstitial lung disease service and offered treatment. These patients had persistent, nonimproving symptoms.Results: At 4 weeks after discharge, 39% of patients reported ongoing symptoms (325/837) and were assessed. Interstitial lung disease, predominantly organizing pneumonia, with significant functional deficit was observed in 35/837 survivors (4.8%). Thirty of these patients received steroid treatment, resulting in a mean relative increase in transfer factor following treatment of 31.6% (standard deviation [SD] ± 27.6, P < 0.001), and forced vital capacity of 9.6% (SD ± 13.0, P = 0.014), with significant symptomatic and radiological improvement.Conclusions: Following SARS-CoV-2 pneumonitis, a cohort of patients are left with both radiological inflammatory lung disease and persistent physiological and functional deficit. Early treatment with corticosteroids was well tolerated and associated with rapid and significant improvement. These preliminary data should inform further study into the natural history and potential treatment for patients with persistent inflammatory ILD following SARS-CoV-2 infection.

A rare cause of secondary organising pneumonia

Non-tuberculous mycobacterial pulmonary disease may have different clinical manifestations. We report a case of a 64-year-old woman presenting with persistent respiratory complaints, fever and radiological findings. Initially, she was diagnosed with community-acquired pneumonia, but after being submitted to an extensive investigation, including CT-guided transthoracic lung biopsy, a diagnosis of organising pneumonia (OP) was established. The patient was treated with corticosteroids with no favourable response. Subsequently, Mycobacterium avium complex (MAC) was identified in bronchoalveolar lavage culture. The patient was diagnosed with OP secondary to MAC infection and specific antibiotic treatment was initiated. This case represents an infrequent association and illustrates how important it is to investigate primary causes of OP to obtain a satisfactory treatment response.

Micronodular pattern organising pneumonia mimicking miliary lung disease: a rare radiological presentation

Organising pneumonia (OP) is an interstitial lung disease characterised by granulation tissues in alveoli and alveolar ducts. Typical imaging findings are migratory airspace opacities with peripheral or peribronchovascular distribution. Diffuse micronodular OP (MNOP) is a rare imaging manifestation, which has imaging differential diagnosis of endobronchial infection such as tuberculosis, hypersensitivity pneumonitis and respiratory bronchiolitis. Although clinical and ancillary radiological findings may aid in refining the differential diagnosis, histopathological assessment is frequently required for this rare presentation due to implications of treatment and prognosis. We report a case of MNOP and performed a review of the literature.

The Significance of Subpleural Sparing in CT Chest: A State-of-the-Art Review

The subpleural sparing pattern is a common finding on computed tomography (CT) of the lungs. It comprises of pulmonary opacities sparing the lung peripheries, typically 1cm and less from the pleural surface. This finding has a variety of causes, including idiopathic, inflammatory, infectious, inhalational, cardiac, traumatic, and bleeding disorders. Specific disorders that can cause subpleural sparing patterns include nonspecific interstitial pneumonia (NSIP), organizing pneumonia (OP), pulmonary alveolar proteinosis (PAP), diffuse alveolar hemorrhage (DAH), vaping-associated lung injury (VALI), cracked lung, pulmonary edema, pneumocystis jirovecii pneumonia (PJP), pulmonary contusion, and more recently, Coronavirus disease 2019 (COVID-19) pneumonia. Knowledge of the many etiologies of this pattern can be useful in preventing diagnostic errors. In addition, although the etiology of subpleural sparing pattern is frequently indistinguishable during an initial radiologic evaluation, the differences in location of opacities in the lungs, as well as the presence of additional radiologic findings, patient history, and clinical presentation, can often be useful to suggest the appropriate diagnosis. We did a comprehensive search on Pubmed and Google Scholar database using keywords of "subpleural sparing," "peripheral sparing," "sparing of peripheries," "CT chest," "chest imaging," and "pulmonary disease." This review aims to describe the primary differential diagnosis of subpleural sparing pattern seen on chest imaging with a strong emphasis on clinical and radiographic findings. We also discuss the pathogenesis and essential clues that are crucial to narrow the differential diagnosis.

Disease-modifying antirheumatic drugs and organising pneumonia

Organising pneumonia (OP) in rheumatoid arthritis (RA) may be part of pulmonary manifestation (disease related) or disease-modifying antirheumatic drugs (DMARDs) related. We report a case series of RA patients with DMARDs related OP. A 65-year-old woman developed OP 3 weeks after initiation of methotrexate (MTX). High-resolution CT (HRCT) scan of the thorax revealed bilateral consolidations in the lung bases. She had complete radiological resolution 6 months after corticosteroid therapy with cessation of MTX. The second case was of a 60-year-old woman on MTX with recent addition of leflunomide due to flare of RA. She developed worsening cough 4 months later and HRCT scan revealed consolidation in the left upper lobe with biopsy proven OP. She responded within 6 months of corticosteroid therapy with clinical and radiological resolution. This case series highlights that OP may developed with low-dose MTX (as early as 3 weeks) and leflunomide and the diagnosis requires a high index of suspicion.

Clinico-etiological characteristics of organizing pneumonia: A retrospective study

Introduction:

Organizing pneumonia (OP) is an idiopathic interstitial pneumonia characterized radiologically by the patchy peripheral areas of ground-glass opacities and consolidation. It is commonly associated with a variety of conditions such as connective tissue diseases (CTD), drugs, infections, malignancy, radiation exposure, post-transplant, and other interstitial pneumonia. There are no specific clinical manifestations unless there is an underlying etiology. We present a series of such cases.

Aims and Objectives:

The aim of the study was to identify the clinical characteristics and etiological spectrum of patients manifesting radiologically with OP pattern.

Materials and Methods:

This was a retrospective analysis of clinico-radiological profile and etiological diagnosis of 23 patients, who had a radiological diagnosis of OP during the period of January 2017–September 2019.

Results:

Our patients presented with nonspecific symptoms of cough, fever, breathlessness, and occasionally with hemoptysis. The various etiologies identified were CTD (n = 4), infection (n = 2), drugs (n = 4), radiation (n = 1), chronic aspiration syndrome (n = 1), malignancy (n = 2), hypersensitivity pneumonitis (n = 1), and chronic heart failure (n = 2), and in majority (n = 7), no underlying etiology was evident and were labeled as cryptogenic organizing pneumonia.

Conclusion:

OP is an underdiagnosed entity and is associated with numerous diseases varying from pulmonary tuberculosis to malignancy. Identification of the underlying disease process is of paramount importance as it enables the treating physician to implement necessary therapeutic interventions.

COVID-19 and its Mimics: What the Radiologist Needs to Know

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for the current outbreak of Coronavirus disease 2019 (COVID-19). Although imaging should not be used for first-line screening or diagnosis, radiologists need to be aware of its imaging features, and those of common conditions that may mimic COVID-19 pneumonia. In this Pictorial Essay, we review frequently encountered conditions with imaging features that overlap with those that are typical of COVID-19 (including other viral pneumonias, chronic eosinophilic pneumonia, and organizing pneumonia), and those with features that are indeterminate for COVID-19 (including hypersensitivity pneumonitis, pneumocystis pneumonia, diffuse alveolar hemorrhage, pulmonary edema, and pulmonary alveolar proteinosis).