Transbronchial Lung Cryobiopsy and Surgical Lung Biopsy: A Prospective Multi-Centre Agreement Clinical Trial (CAN-ICE)

A Brief Guide to Interpreting Transbronchial Cryobiopsies for Diffuse Parenchymal Lung Disease

Transbronchial cryobiopsies (CB) are increasingly replacing surgical biopsies (video-assisted thoracoscopic/VATS biopsies) for diagnosing diffuse parenchymal lung disease (interstitial lung disease, ILD), but there is very little guidance for pathologists on CB interpretation. Here we propose a fairly simple approach. First, if the diagnosis can be made on a traditional forceps biopsy, it can be made on a cryobiopsy. Many diseases with specific features will fall into this category (eg, sarcoidosis or Langerhans cell histiocytosis). More problematic are patterns such as usual interstitial pneumonia (UIP) or nonspecific interstitial pneumonia (NSIP), in which low-power architecture is the key to diagnosis. In this circumstance, an adequate sample is crucial to look for features such as fibroblast foci, because a combination of fibroblast foci plus any patchy old fibrosis, fibrotic architectural remodeling, or honeycombing, allows a diagnosis of a UIP pattern. However, in most instances, CB will not separate the UIP patterns seen in idiopathic pulmonary fibrosis, fibrotic hypersensitivity pneumonitis, or connective tissue disease-interstitial lung disease (CTD-ILD), although giant cells/granulomas (uncommon findings) in this setting favor fibrotic hypersensitivity pneumonitis. Fibroblast foci can be difficult to differentiate from organizing pneumonia (OP), but granulation tissue plugs clearly in airspaces favor OP. Absent fibroblast foci, patchy old fibrosis, architectural distortion, and honeycombing by themselves do not allow a specific diagnosis. NSIP in CB microscopically looks like NSIP in VATS biopsies, and the presence of an NSIP or an NSIP+OP pattern is typical of CTD-ILD. All the above diagnoses require correlation with clinical and radiologic findings.

The Role of Bronchoscopy in the Diagnosis of Interstitial Lung Disease: A State-of-the-Art Review

The diagnostic evaluation of interstitial lung diseases (ILDs) remains challenging due to their heterogeneous etiologies and overlapping clinical and radiographic patterns. A confident diagnosis often necessitates histopathological sampling, particularly when high-resolution computed tomography and serologic assessments are inconclusive. While surgical lung biopsy (SLB) has long been considered the diagnostic gold standard, its invasiveness, associated morbidity, and limited feasibility in high-risk patients have driven the pursuit of less invasive alternatives. Here, we review the current applications, diagnostic yield, procedural techniques, and complications of several bronchoscopic modalities. Bronchoalveolar lavage (BAL) aids in characterizing inflammatory profiles and differentiating among conditions such as hypersensitivity pneumonitis, sarcoidosis, and eosinophilic pneumonia. Endobronchial biopsies (EBBs) and endobronchial ultrasound transbronchial needle aspiration (EBUS-TBNA) are valuable in diagnosing granulomatous diseases with lymphadenopathy. Transbronchial lung biopsy (TBLB) is effective for peribronchial and centrilobular diseases but is limited by small sample size and tissue distortion. Transbronchial lung cryobiopsy (TBC) enables acquisition of larger, well-preserved parenchymal tissue samples from the peripheral lung. Over recent years, studies have demonstrated that TBC, when interpreted within a multidisciplinary discussion (MDD), achieves diagnostic concordance rates with SLB exceeding 75%, and up to 95% in cases where high diagnostic confidence is reached. When performed in experienced centers using standardized protocols, TBC is considered a viable first-line histopathologic tool in the diagnostic evaluation of ILD. Adequate training and standardization of the TBC procedure are needed to ensure low complication rates and a high yield.

Updates in Diagnostic Tools for ILD

Interstitial lung disease (ILD) is a group of diffuse parenchymal disorders, which are diagnosed in many cases by multidisciplinary discussion (MDD). In some cases, diagnosis can be challenging, and the addition of histopathology can increase diagnostic confidence. The tools to obtain a histopathological sample to diagnose ILD are expanding. In this review, we will discuss the various modalities, their sensitivities and specificities, and procedural complication rates. In this review, we conducted a comprehensive review of literature focusing on emerging and established diagnostic tools for ILD. A systematic search of peer-reviewed publications was performed using PubMed with a focus on clinical trials, retrospective and prospective cohort studies, and systematic reviews. The key diagnostic modalities in focus were genomic classifier (GC), transbronchial cryobiopsy (TBLC), surgical lung biopsy (SLB), endobronchial ultrasound cryobiopsy (EBUS-C), genetic testing, and speckled transthoracic echocardiography (STE). Data extracted from these studies focused on diagnostic yield, specificity, sensitivity, and procedural complication rate. Genomic classifier, a gene-based molecular diagnostic tool, has a high specificity for histological usual interstitial pneumonia (UIP). However, in cases of a negative result, it often results in a need for further invasive sampling by TBLC or SLB. TBLC results in a larger histological sample, which can increase diagnostic yield and increase diagnostic confidence at MDD. Recent prospective trials have compared this modality with SLB and found 63-77% interobserver agreement between pathologists. SLB remains the gold standard with diagnostic yields reported to be more than 90%. EBUS-C has shown promising results increasing diagnostic yield in patients with suspected sarcoidosis or lymphoma. All diagnostic modalities have procedural complications with most common being pneumothorax, bleeding and, rarely, death. Advancements in diagnostic tools for interstitial lung disease (ILD) have significantly improved accuracy. Even though surgical lung biopsy remains the gold standard, the alternative modalities are promising and provide a promising yield with a lower procedural risk.

Advances in management of pulmonary fibrosis

Pulmonary fibrosis care, affecting both idiopathic pulmonary fibrosis and other forms of interstitial lung disease (ILD) characterised by fibrosis, has transformed with a range of innovations that affect the diagnosis, treatment and prognosis of this condition. Pharmacotherapeutic options have expanded, with increased indications for the application of effective antifibrotic therapy in non-IPF progressive pulmonary fibrosis as a solo treatment or combined with immunosuppression, emerging evidence for immunomodulatory therapy including biologic agents and greater access to clinical trials. The diagnostic approach to unclassifiable ILD now includes transbronchial lung cryobiopsy, a less invasive method to obtain histopathology with reduced morbidity and mortality compared to surgical lung biopsy. A multidisciplinary approach optimises the care of people with ILD and includes non-pharmacological management, addressing significant comorbidities, symptom care and advanced care planning. This review will summarise recent updates in pulmonary fibrosis management.

Advances in idiopathic pulmonary fibrosis diagnosis and treatment

Significant advances have been made in diagnosing and treating idiopathic pulmonary fibrosis (IPF) in the last decade. The incidence and prevalence of IPF are increasing, and morbidity and mortality remain high despite the two Food and Drug Administration (FDA)-approved medications, pirfenidone and nintedanib. Hence, there is an urgent need to develop new diagnostic tools and effective therapeutics to improve early, accurate diagnosis of IPF and halt or reverse the progression of fibrosis with a better safety profile. New diagnostic tools such as transbronchial cryobiopsy and genomic classifier require less tissue and generally have good safety profiles, and they have been increasingly utilized in clinical practice. Advances in artificial intelligence-aided diagnostic software are promising, but challenges remain. Both pirfenidone and nintedanib focus on growth factor-activated pathways to inhibit fibroblast activation. Novel therapies targeting different pathways and cell types (immune and epithelial cells) are being investigated. Biomarker-based personalized medicine approaches are also in clinical trials. This review aims to summarize recent diagnostic and therapeutic development in IPF.

Cryoprobe biopsy versus mechanical biopsies in pulmonary diagnostics

PURPOSE OF REVIEW

Biopsy tools have been essential in improving the diagnostic accuracy of bronchoscopic procedures. Of these tools, cryobiopsy has emerged as a promising technique for diagnosing thoracic diseases. This review summarizes the existing data comparing cryobiopsies to other mechanical biopsy methods for sampling endobronchial, parenchymal, and mediastinal targets.

RECENT FINDINGS

Initially adopted for managing airway stenoses, the use of cryoprobes has expanded to diagnosing endobronchial lesions, parenchymal opacities, and mediastinal lymph node pathologies. Studies have demonstrated that cryobiopsy offers a higher diagnostic yield than forceps biopsy alone. By leveraging the Joule-Thomson effect to freeze and collect larger tissue samples compared to traditional methods, cryobiopsy improves diagnostic accuracy and helps in better characterizing the nature of the lesions. While the risk of complications, such as pneumothorax and hemorrhage are comparable to, or higher than traditional biopsy methods, cryobiopsy's enhanced diagnostic capabilities make it a valuable tool in the assessment of pulmonary disease.

SUMMARY

Compared with other mechanical biopsy techniques, cryoprobe biopsies significantly enhance the diagnostic yield for endobronchial lesions, interstitial lung disease, pulmonary nodules, and mediastinal lymph nodes.

Pathological features of connective tissue disease-associated interstitial lung disease in transbronchial cryobiopsies

AIM

Transbronchial cryobiopsies are increasingly used for the diagnosis of interstitial lung disease (ILD), but there is a lack of published information on the features of specific ILD in cryobiopsies. Here we attempt to provide pathological guidelines for separating usual interstitial pneumonia (UIP) of idiopathic pulmonary fibrosis (IPF), fibrotic hypersensitivity pneumonitis (FHP) and connective tissue disease-associated ILD (CTD-ILD) in cryobiopsies.

METHODS

We examined 120 cryobiopsies from patients with multidisciplinary discussion (MDD)-established CTD-ILD and compared them to a prior series of 121 biopsies from patients with MDD-established IPF or FHP.

RESULTS

A non-specific interstitial pneumonia (NSIP) pattern alone was seen in 36 of 120 (30%) CTD-ILD, three of 83 (3.6%) FHP and two of 38 (5.2%) IPF cases, statistically favouring a diagnosis of CTD-ILD. The combination of NSIP + OP was present in 29 of 120 (24%) CTD-ILD, two of 83 (2.4%) FHP and none of 38 (0%) IPF cases, favouring a diagnosis of CTD-ILD. A UIP pattern, defined as fibroblast foci plus any of patchy old fibrosis/fibrosis with architectural distortion/honeycombing, was identified in 28 of 120 (23%) CTD-ILD, 45 of 83 (54%) FHP and 27 of 38 (71%) IPF cases and supported a diagnosis of FHP or IPF. The number of lymphoid aggregates/mm2 and fibroblast foci/mm2 was not different in IPF, CTD-ILD or FHP cases with a UIP pattern. Interstitial giant cells supported a diagnosis of FHP or CTD-ILD over IPF, but were infrequent.

CONCLUSIONS

In the correct clinical/radiological context the pathological findings of NSIP, and particularly NSIP plus OP, favour a diagnosis of CTD-ILD in a cryobiopsy, but CTD-ILD with a UIP pattern, FHP with a UIP pattern and IPF generally cannot be distinguished.

Contemporary Concise Review 2023: Interstitial lung disease

In this review, we have discussed several important developments in 2023 in Interstitial Lung Disease (ILD). The association of pollution with genetic predispositions increased the risk of Idiopathic Pulmonary Fibrosis (IPF). An interesting comorbidity of malnutrition was not adequately recognized in ILD. Novel genes have been identified in IPF involving predominantly short telomere length and surfactant protein production leading to alveolar epithelial cell dysfunction. Genetics also predicted progression in IPF. Crosstalk between vascular endothelial cells and fibroblasts in IPF mediated by bone morphogenic protein signalling may be important for remodelling of the lung. A novel modality for monitoring of disease included the 4-min gait speed. New treatment modalities include inhaled pirfenidone, efzofitimod, for sarcoidosis, and earlier use of immunosuppression in connective tissue disease-ILD.

The Diagnostic Efficiency and Safety of Transbronchial Lung Cryobiopsy Using 1.1-mm Cryoprobe in Diagnosing Interstitial Lung Disease

INTRODUCTION

Transbronchial lung cryobiopsy (TBLC) is increasingly used to diagnose interstitial lung disease (ILD). The 1.1-mm cryoprobe has recently been available in clinical practice. The diagnostic yield and safety of TBLC using a 1.1-mm cryoprobe need to be confirmed.

METHODS

A prospective, randomized controlled trial was conducted in patients with suspected ILD and randomly assigned to 1.1-mm and 1.9-mm cryoprobe groups. The primary outcome was the diagnostic yield of multidisciplinary discussion. Secondary outcomes were sample quality and incidence of complications. The tension and stress effects during TBLC onto the target lobe caused by 1.1-mm and 1.9-mm cryoprobes were also evaluated using finite element analysis.

RESULTS

A total of 224 patients were enrolled. No significant differences were observed in the diagnostic yield (80.4% vs. 79.5%, p = 0.845) and sample quality scores (5.73 ± 0.64 vs. 5.66 ± 0.77; p = 0.324) between the 1.9-mm cryoprobe group and 1.1-mm cryoprobe group. The average surface areas of samples in 1.1-mm cryoprobe group were smaller, while no difference in sample weights was observed. A decreased incidence of moderate bleeding was found in the 1.1-mm cryoprobe group (17.0% vs. 6.2%, p = 0.027), while there was no difference in the incidence of the pneumothorax, there was a trend to higher rate of pneumothorax in 1.1-mm group. In finite element analysis, the 1.1-mm cryoprobe required the largest tension and produced the largest stress.

CONCLUSION

Compared with a 1.9-mm cryoprobe, there was no difference in specimen quality or diagnostic rate but smaller sample size with a 1.1-mm cryoprobe. There was a decreased risk of moderate bleeding, but a trend towards increased risk for pneumothorax with 1.1-mm cryoprobe.

TRAIL REGISTRATION

Clinicaltrials.gov identifier NCT04047667; registered August 4, 2019.

Impact of surgical lung biopsy on lung function and survival in patients with idiopathic pulmonary fibrosis in a multi-centre registry cohort

BACKGROUND AND OBJECTIVE

Establishing an accurate and timely diagnosis of idiopathic pulmonary fibrosis (IPF) is essential for appropriate management and prognostication. In some cases, surgical lung biopsy (SLB) is performed but carries non-negligible risk. The objective of this retrospective study was to determine if SLB is associated with accelerated lung function decline in patients with IPF using the Canadian Registry for Pulmonary Fibrosis.

METHODS

Linear mixed models and Cox proportional hazards regression models were used to compare decline in forced vital capacity (FVC)%, diffusion capacity of the lung (DLCO%) and risk of death or lung transplantation between SLB and non-SLB patients. Adjustments were made for baseline age, sex, smoking history, antifibrotic use, and lung function. A similar analysis compared lung function changes 12 months pre- and post-SLB.

RESULTS

A total of 81 SLB patients and 468 non-SLB patients were included. In the SLB group, the post-biopsy annual FVC% decline was 2.0% (±0.8) in unadjusted, and 2.1% (±0.8) in adjusted models. There was no difference in FVC% decline, DLCO% decline, or time to death or lung transplantation between the two groups, in adjusted or unadjusted models (all p-values >0.07). In the pre-post SLB group, no differences were identified in FVC% decline in unadjusted or adjusted models (p = 0.07 for both).

CONCLUSION

No association between SLB and lung function decline or risk of death or lung transplantation was identified in this multi-centre study of patients with IPF.

A systematic review of procedural and sampling techniques for cryobiopsy in interstitial lung disease

BACKGROUND

Transbronchial lung cryobiopsy (TBLC) is an alternative to surgical lung biopsy for histopathological evaluation of unclassifiable interstitial lung disease (ILD) or ILD diagnosed with low confidence. This meta-analysis synthesised current literature regarding cryobiopsy diagnostic performance and safety, focusing on procedural and sampling techniques.

METHODS

Medline and Embase were searched on 11 April 2022. Studies included adults with unclassifiable ILD, reporting diagnostic yield, complications and methodological techniques of TBLC. Meta-analyses were performed for diagnostic yield, pneumothorax and bleeding. Subgroup analyses and meta-regression assessed methodological variables. PROSPERO registration: CRD42022312386.

RESULTS

70 studies were included with 6183 participants. Diagnostic yield of TBLC was 81% (95% CI 79-83%, I2=97%), with better yield being observed with general anaesthesia (p=0.007), ILD multidisciplinary meeting prior to cryobiopsy (p=0.02), 2.4 mm cryoprobe (p=0.04), higher mean forced vital capacity (p=0.046) and higher mean diffusing capacity for carbon monoxide (p=0.023). Pneumothorax rate was 5% (95% CI 4-5%, I2=91%), with higher rates associated with a 2.4 mm cryoprobe (p<0.00001), routine post-procedure imaging (p<0.00001), multiple lobe sampling (p<0.0001), reduced mean diffusing capacity for carbon monoxide (p=0.028) and general anaesthesia (p=0.05). Moderate-to-severe bleeding rate was 12% (11-14%, I2=95%) and higher rates were associated with a 2.4 mm cryoprobe (p=0.001) and bleeding score selection (p=0.04).

INTERPRETATION

Patient characteristics and modifiable factors, including procedural methods and anaesthetic techniques, impacted diagnostic yield and safety outcomes of TBLC in people with unclassifiable ILD and contributed to heterogeneity of clinical outcomes. These variables should be considered for individualised clinical decision making and guideline development and warrant routine reporting in future research.

Transbronchial cryobiopsy followed by as-needed surgical lung biopsy versus immediate surgical lung biopsy for diagnosing interstitial lung disease (the COLD study): a randomised controlled trial

BACKGROUND

An adequate diagnosis for interstitial lung disease (ILD) is important for clinical decision making and prognosis. In most patients with ILD, an accurate diagnosis can be made by clinical and radiological data assessment, but in a considerable proportion of patients, a lung biopsy is required. Surgical lung biopsy (SLB) is the most common method to obtain tissue, but it is associated with high morbidity and even mortality. More recently, transbronchial cryobiopsy has been introduced, with fewer adverse events but a lower diagnostic yield than SLB. The aim of this study is to compare two diagnostic strategies: a step-up strategy (transbronchial cryobiopsy, followed by SLB if the cryobiopsy is insufficiently informative) versus immediate SLB.

METHODS

The COLD study was a multicentre, randomised controlled trial in six hospitals across the Netherlands. We included patients with ILD with an indication for lung biopsy as assessed by a multidisciplinary team discussion. Patients were randomly assigned in a 1:1 ratio to the step-up or immediate SLB strategy, with follow-up for 12 weeks from the initial procedure. Patients, clinicians, and pathologists were not masked to the study treatment. The primary endpoint was unexpected chest tube drainage, defined as requiring any chest tube after transbronchial cryobiopsy, or prolonged (>24 h) chest tube drainage after SLB. Secondary endpoints were diagnostic yield, in-hospital stay, pain, and serious adverse events. A modified intention-to-treat analysis was performed. This trial is registered with the Dutch Trial Register, NL7634, and is now closed.

FINDINGS

Between April 8, 2019, and Oct 24, 2021, 122 patients with ILD were assessed for study participation; and 55 patients were randomly assigned to the step-up strategy (n=28) or immediate SLB (n=27); three patients from the immediate SLB group were excluded. Unexpected chest tube drainage occurred in three of 28 patients (11%; 95% CI 4-27%) in the step-up group, and the number of patients for whom the chest tube could not be removed within 24 h was 11 of 24 patients (46%; 95% CI 2-65%) in the SLB group, with an absolute risk reduction of 35% (11-56%; p=0·0058). In the step-up strategy, the multidisciplinary team diagnostic yield after transbronchial cryobiopsy alone was 82% (64-92%), which increased to 89% (73-96%) when subsequent SLB was performed after inconclusive transbronchial cryobiopsy. In the immediate surgery strategy, the multidisciplinary team diagnostic yield was 88% (69-97%). Total in-hospital stay was 1 day (IQR 1-1) in the step-up group versus 5 days (IQR 4-6) in the SLB group. One (4%) serious adverse event occurred in step-up strategy versus 12 (50%) in the immediate SLB strategy.

INTERPRETATION

In ILD diagnosis, if lung tissue assessment is required, a diagnostic strategy starting with transbronchial cryobiopsy, followed by SLB when transbronchial cryobiopsy is inconclusive, appears to result in a significant reduction of patient burden and in-hospital stay with a similar diagnostic yield versus immediate SLB.

FUNDING

Netherlands Organisation for Health Research and Development (ZonMW) and Amsterdam University Medical Centers.

A Review of Endobronchial-Ultrasound-Guided Transbronchial Intranodal Forceps Biopsy and Cryobiopsy

Benign and malignant mediastinal lesions are not infrequently encountered in clinical practice. Mediastinoscopy has long been considered the gold standard in evaluating mediastinal pathology. Since its introduction into clinical practice, endobronchial-ultrasonography-guided transbronchial fine needle aspiration (EBUS-TBNA) has replaced mediastinoscopy as the initial procedure of choice to evaluate mediastinal lesions and to stage lung cancer. Its diagnostic yield in benign mediastinal lesions and less common malignancies, however, has remained limited. This has led different proceduralists to investigate additional procedures to improve the diagnostic yield of EBUS-TBNA. In recent years, different published reports concluded that the addition of EBUS-guided intranodal forceps biopsy (IFB) and transbronchial cryobiopsy (TBCB) to EBUS-TBNA increases the diagnostic yield especially in benign mediastinal lesions and uncommon mediastinal malignancies. The purpose of this review is to describe how EBUS-IFB and EBUS-TBCB are performed, to compare their diagnostic yields, and to discuss their limitations and their potential complications. In addition, the review will conclude with a proposed algorithm on how to incorporate EBUS-IFB and EBUS-TBCB into clinical practice.

Relationship between idiopathic interstitial pneumonias (IIPs) and connective tissue disease-related interstitial lung disease (CTD-ILD): A narrative review

While idiopathic interstitial pneumonia (IIP) centering on idiopathic pulmonary fibrosis (IPF) is the most prevalent interstitial lung disease (ILD), especially in the older adult population, connective tissue disease (CTD)-related ILD is the second most prevalent ILD. The pathogenesis of IPF is primarily fibrosis, whereas that of other ILDs, particularly CTD-ILD, is mainly inflammation. Therefore, a precise diagnosis is crucial for selecting appropriate treatments, such as antifibrotic or immunosuppressive agents. In addition, some patients with IIP have CTD-related features, such as arthritis and skin eruption, but do not meet the criteria for any CTD, this is referred to as interstitial pneumonia with autoimmune features (IPAF). IPAF is closely associated with idiopathic nonspecific interstitial pneumonia (iNSIP) and cryptogenic organizing pneumonia (COP). Furthermore, patients with iNSIP or those with NSIP with OP overlap frequently develop polymyositis/dermatomyositis after the diagnosis of IIP. Acute exacerbation of ILD, the most common cause of death, occurs more frequently in patients with IPF than in those with other ILDs. Although acute exacerbation of CTD-ILD occurs at a low rate of incidence, patients with rheumatoid arthritis, microscopic polyangiitis, or systemic sclerosis experience more acute exacerbation of CTD-ILD than those with other CTD. In this review, the features of each IIP, focusing on CTD-related signatures, are summarized, and the pathogenesis and appropriate treatments to improve the prognoses of patients with various ILDs are discussed.

Multidisciplinary Approach to the Diagnosis of Idiopathic Interstitial Pneumonias: Focus on the Pathologist's Key Role

Idiopathic Interstitial Pneumonias (IIPs) are a heterogeneous group of the broader category of Interstitial Lung Diseases (ILDs), pathologically characterized by the distortion of lung parenchyma by interstitial inflammation and/or fibrosis. The American Thoracic Society (ATS)/European Respiratory Society (ERS) international multidisciplinary consensus classification of the IIPs was published in 2002 and then updated in 2013, with the authors emphasizing the need for a multidisciplinary approach to the diagnosis of IIPs. The histological evaluation of IIPs is challenging, and different types of IIPs are classically associated with specific histopathological patterns. However, morphological overlaps can be observed, and the same histopathological features can be seen in totally different clinical settings. Therefore, the pathologist's aim is to recognize the pathologic-morphologic pattern of disease in this clinical setting, and only after multi-disciplinary evaluation, if there is concordance between clinical and radiological findings, a definitive diagnosis of specific IIP can be established, allowing the optimal clinical-therapeutic management of the patient.

Pathologic Criteria for the Diagnosis of Usual Interstitial Pneumonia vs Fibrotic Hypersensitivity Pneumonitis in Transbronchial Cryobiopsies

Transbronchial cryobiopsy (TBCB) is increasingly used for the diagnosis of fibrosing interstitial pneumonias, but there are few detailed descriptions of the pathologic findings in such cases. It has been proposed that a combination of patchy fibrosis and fibroblast foci with an absence of alternative features is diagnostic of usual interstitial pneumonia (UIP; ie, idiopathic pulmonary fibrosis [IPF]) in TBCB. In this study, we reviewed 121 TBCB in which a diagnosis of fibrotic hypersensitivity pneumonitis (FHP; n = 83) or IPF (n = 38) was made by multidisciplinary discussion and evaluated a range of pathologic features. Patchy fibrosis was found in 65 of 83 (78%) biopsies from FHP and 32of 38 (84%) biopsies from UIP/IPF cases. Fibroblast foci were present in 47 of 83 (57%) FHP and 27 of 38 (71%) UIP/IPF cases. Fibroblast foci/patchy fibrosis combined did not favor either diagnosis. Architectural distortion was seen in 54 of 83 (65%) FHP and 32 of 38 (84%) UIP/IPF cases (odds ratio [OR] for FHP, 0.35; P = .036) and honeycombing in 18 of 83 (22%) and 17 of 38 (45%), respectively (OR, 0.37; P = .014). Airspace giant cells/granulomas were present in 13 of 83 (20%) FHP and 1 of 38 (2.6%) UIP/IPF cases (OR for FHP, 6.87; P = .068), and interstitial giant cells/granulomas in 20 of 83 (24%) FHP and 0 of 38 (0%) UIP/IPF (OR, 6.7 x 106; P = .000). We conclude that patchy fibrosis plus fibroblast foci can be found in TBCB from both FHP and UIP/IPF. The complete absence of architectural distortion/honeycombing favors a diagnosis of FHP, as does the presence of airspace or interstitial giant cells/granulomas, but these measures are insensitive, and many cases of FHP cannot be separated from UIP/IPF on TBCB.

The Characteristic of Transbronchial Lung Cryobiopsy in the Pathological Diagnosis of Hypersensitivity Pneumonitis

BACKGROUND

Transbronchial lung cryobiopsy (TBLC) has widely used for the diagnosis of diffuse lung disease. However, it remains unclear whether TBLC is useful for the diagnosis in hypersensitivity pneumonitis (HP).

METHODS

We investigated 18 patients who underwent TBLC and were diagnosed with HP based on pathology or multidisciplinary discussion (MDD). Of the 18 patients, 12 had fibrotic HP (fHP), 2 had non-fibrotic HP (non-fHP) diagnosed with MDD. The remaining 4 patients were diagnosed with fHP by pathology but not by MDD because of clinical features. The radiology and pathology of these cases were compared.

RESULTS

All patients with fHP showed radiological findings of inflammation, fibrosis, and airway disease. Conversely, pathology showed fibrosis and inflammation in 11 of 12 cases (92%), but airway disease was significantly less common with 5 cases (42%) (p = 0.014). Non-fHP showed inflammatory cell infiltration mainly in the centrilobule on pathology, which was consistent with radiology. Granulomas were found in 5 patients with HP (36%). In the non-HP group, airway-centered interstitial fibrosis was observed in 3 patients (75%) with pathology.

CONCLUSIONS

The pathology with TBLC is difficult to evaluate airway disease of HP. We need to understand this characteristic of TBLC to make a MDD diagnosis of HP.