Diffuse pulmonary meningotheliomatosis with pan-TRK expression by immunohistochemistry: a novel finding and potential pitfall.

BACKGROUND: Pulmonary meningothelial-like nodules (PMNs) are benign proliferations of unclear clinical significance. They are mainly asymptomatic lesions that are usually discovered during the pathologic evaluation of resected pulmonary specimens or following post-mortem examination. Diffuse pulmonary meningotheliomatosis (DPM), which presents as bilateral multiple PMNs throughout the lungs, has been described less frequently. DPMs are benign lesions associated with both neoplastic and non-neoplastic pulmonary conditions. CASE PRESENTATION: We report the case of a 59-year-old female patient who presented with a history of cough. Computerized tomography (CT) imaging revealed multiple subcentimeter bilateral pulmonary nodules. transbronchial biopsies were obtained which revealed foci of nodular interstitial proliferations composed of epithelioid to spindled cells in a vague whorled pattern. Immunohistochemical stains were diffusely positive for EMA and progesterone receptor. Furthermore, pan-TRK exhibited strong and diffuse membranous expression in the lesional cells. INSM1 was negative for expression. RNA-based next-generation sequencing for the detection of NTRK fusions was performed and was negative for gene rearrangements involving NTRK1, NTRK2, and NTRK3. CONCLUSION: Here, we report a rare case of DPM and report pan-TRK expression in PMNs which has not been described. We provide a brief review of the literature and provide insight into the potential physiologic nature of PMNs. Lastly, we emphasize the recognition of pan-TRK immunoexpression in PMNs to avoid potential diagnostic errors.

NAVIGATE 24-Month Results: Electromagnetic Navigation Bronchoscopy for Pulmonary Lesions at 37 Centers in Europe and the United States.

INTRODUCTION: Electromagnetic navigation bronchoscopy (ENB) is a minimally invasive, image-guided approach to access lung lesions for biopsy or localization for treatment. However, no studies have reported prospective 24-month follow-up from a large, multinational, generalizable cohort. This study evaluated ENB safety, diagnostic yield, and usage patterns in an unrestricted, real-world observational design. METHODS: The NAVIGATE single-arm, pragmatic cohort study (NCT02410837) enrolled subjects at 37 academic and community sites in seven countries with prospective 24-month follow-up. Subjects underwent ENB using the superDimension navigation system versions 6.3 to 7.1. The prespecified primary end point was procedure-related pneumothorax requiring intervention or hospitalization. RESULTS: A total of 1388 subjects were enrolled for lung lesion biopsy (1329; 95.7%), fiducial marker placement (272; 19.6%), dye marking (23; 1.7%), or lymph node biopsy (36; 2.6%). Concurrent endobronchial ultrasound-guided staging occurred in 456 subjects. General anesthesia (78.2% overall, 56.6% Europe, 81.4% United States), radial endobronchial ultrasound (50.6%, 4.0%, 57.4%), fluoroscopy (85.0%, 41.7%, 91.0%), and rapid on-site evaluation use (61.7%, 17.3%, 68.5%) differed between regions. Pneumothorax and bronchopulmonary hemorrhage occurred in 4.7% and 2.7% of subjects, respectively (3.2% [primary end point] and 1.7% requiring intervention or hospitalization). Respiratory failure occurred in 0.6%. The diagnostic yield was 67.8% (range: 61.9%-70.7%; 55.2% Europe, 69.8% United States). Sensitivity for malignancy was 62.6%. Lung cancer clinical stage was I to II in 64.7% (55.3% Europe, 65.8% United States). CONCLUSIONS: Despite a heterogeneous cohort and regional differences in procedural techniques, ENB demonstrates low complications and a 67.8% diagnostic yield while allowing biopsy, staging, fiducial placement, and dye marking in a single procedure.

Standardized Definitions of Bleeding After Transbronchial Lung Biopsy: A Delphi Consensus Statement From the Nashville Working Group.

BACKGROUND: Transbronchial lung biopsies are commonly performed for a variety of indications. Although generally well tolerated, complications such as bleeding do occur. Description of bleeding severity is crucial both clinically and in research trials; to date, there is no validated scale that is widely accepted for this purpose. Can a simple, reproducible tool for categorizing the severity of bleeding after transbronchial biopsy be created? METHODS: Using the modified Delphi method, an international group of bronchoscopists sought to create a new scale tailored to assess bleeding severity among patients undergoing flexible bronchoscopy with transbronchial lung biopsies. Cessation criteria were specified a priori and included reaching > 80% consensus among the experts or three rounds, whichever occurred first. RESULTS: Thirty-six expert bronchoscopists from eight countries, both in academic and community practice settings, participated in the creation of the scale. After the live meeting, two iterations were made. The second and final scale was vetted by all 36 participants, with a weighted average of 4.47/5; 53% were satisfied, and 47% were very satisfied. The panel reached a consensus and proposes the Nashville Bleeding Scale. CONCLUSIONS: The use of a simplified airway bleeding scale that can be applied at bedside is an important, necessary tool for categorizing the severity of bleeding. Uniformity in reporting clinically significant airway bleeding during bronchoscopic procedures will improve the quality of the information derived and could lead to standardization of management. In addition to transbronchial biopsies, this scale could also be applied to other bronchoscopic procedures, such as endobronchial biopsy or endobronchial ultrasound-guided needle aspiration.

Fiducial marker placement with electromagnetic navigation bronchoscopy: a subgroup analysis of the prospective, multicenter NAVIGATE study.

BACKGROUND: Fiducial markers (FMs) help direct stereotactic body radiation therapy (SBRT) and localization for surgical resection in lung cancer management. We report the safety, accuracy, and practice patterns of FM placement utilizing electromagnetic navigation bronchoscopy (ENB). METHODS: NAVIGATE is a global, prospective, multicenter, observational cohort study of ENB using the superDimension™ navigation system. This prospectively collected subgroup analysis presents the patient demographics, procedural characteristics, and 1-month outcomes in patients undergoing ENB-guided FM placement. Follow up through 24 months is ongoing. RESULTS: Two-hundred fifty-eight patients from 21 centers in the United States were included. General anesthesia was used in 68.2%. Lesion location was confirmed by radial endobronchial ultrasound in 34.5% of procedures. The median ENB procedure time was 31.0 min. Concurrent lung lesion biopsy was conducted in 82.6% (213/258) of patients. A mean of 2.2 ± 1.7 FMs (median 1.0 FMs) were placed per patient and 99.2% were accurately positioned based on subjective operator assessment. Follow-up imaging showed that 94.1% (239/254) of markers remained in place. The procedure-related pneumothorax rate was 5.4% (14/258) overall and 3.1% (8/258) grade ⩾ 2 based on the Common Terminology Criteria for Adverse Events scale. The procedure-related grade ⩾ 4 respiratory failure rate was 1.6% (4/258). There were no bronchopulmonary hemorrhages. CONCLUSION: ENB is an accurate and versatile tool to place FMs for SBRT and localization for surgical resection with low complication rates. The ability to perform a biopsy safely in the same procedure can also increase efficiency. The impact of practice pattern variations on therapeutic effectiveness requires further study. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT02410837.

Safety of Electromagnetic Navigation Bronchoscopy in Patients With COPD: Results From the NAVIGATE Study.

BACKGROUND: Electromagnetic navigation bronchoscopy (ENB) aids in the localization of lung lesions for biopsy and/or to guide fiducial or dye marking for stereotactic radiation or surgical localization. This study assessed ENB safety in patients with chronic obstructive pulmonary disease (COPD) and/or poor lung function. METHODS: NAVIGATE is a prospective, multicenter, observational study of ENB. This substudy analyzed the 1-month follow-up of the first 1000 enrolled subjects. COPD was determined by medical history. Pulmonary function testing (PFT) results were collected if available within 30 days of the procedure. Procedure-related complications were captured. RESULTS: The analysis included 448 subjects with COPD and 541 without COPD (COPD data missing in 11). One-month follow-up was completed in 93.3%. Subjects with COPD tended to be older, male, and have history of tobacco exposure, asthma, and recent pneumonia. Nodule size, location, and procedure time were similar between groups. There was no statistically significant difference in the procedure-related composite complication rate between groups (7.4% with COPD, 7.8% without COPD, P=0.90). Common Terminology Criteria for Adverse Events scale grade ≥2 pneumothorax was not different between groups (2.7% with COPD, 3.7% without COPD, P=0.47). COPD was not a significant multivariate predictor of complications. Severity of forced expiratory volume in 1 second (FEV1) or diffusing capacity of the lung for carbon monoxide impairment was not associated with increased composite procedure-related complications (ppFEV1 P=0.66, ppDLCO P=0.36). CONCLUSION: In this analysis, complication rates following ENB procedures were not increased in patients with COPD or poor pulmonary function. Because pneumothorax risk is not elevated, ENB may be the preferred method to biopsy peripheral lung lesions in patients with COPD and/or poor pulmonary function testing.

Electromagnetic Navigation Bronchoscopy for Peripheral Pulmonary Lesions: One-Year Results of the Prospective, Multicenter NAVIGATE Study.

INTRODUCTION: Electromagnetic navigation bronchoscopy (ENB) is a minimally invasive technology that guides endoscopic tools to pulmonary lesions. ENB has been evaluated primarily in small, single-center studies; thus, the diagnostic yield in a generalizable setting is unknown. METHODS: NAVIGATE is a prospective, multicenter, cohort study that evaluated ENB using the superDimension navigation system (Medtronic, Minneapolis, Minnesota). In this United States cohort analysis, 1215 consecutive subjects were enrolled at 29 academic and community sites from April 2015 to August 2016. RESULTS: The median lesion size was 20.0 mm. Fluoroscopy was used in 91% of cases (lesions visible in 60%) and radial endobronchial ultrasound in 57%. The median ENB planning time was 5 minutes; the ENB-specific procedure time was 25 minutes. Among 1157 subjects undergoing ENB-guided biopsy, 94% (1092 of 1157) had navigation completed and tissue obtained. Follow-up was completed in 99% of subjects at 1 month and 80% at 12 months. The 12-month diagnostic yield was 73%. Pathology results of the ENB-aided tissue samples showed malignancy in 44% (484 of 1092). Sensitivity, specificity, positive predictive value, and negative predictive value for malignancy were 69%, 100%, 100%, and 56%, respectively. ENB-related Common Terminology Criteria for Adverse Events grade 2 or higher pneumothoraces (requiring admission or chest tube placement) occurred in 2.9%. The ENB-related Common Terminology Criteria for Adverse Events grade 2 or higher bronchopulmonary hemorrhage and grade 4 or higher respiratory failure rates were 1.5% and 0.7%, respectively. CONCLUSIONS: NAVIGATE shows that an ENB-aided diagnosis can be obtained in approximately three-quarters of evaluable patients across a generalizable cohort based on prospective 12-month follow-up in a pragmatic setting with a low procedural complication rate.

Integrin beta6 mediates phospholipid and collectin homeostasis by activation of latent TGF-beta1.

Surfactant lines the alveolar surface and prevents alveolar collapse. Derangements of surfactant cause respiratory failure and interstitial lung diseases. The collectins, surfactant proteins A and D, are also important in innate host defense. However, surfactant regulation in the postnatal lung is poorly understood. We found that the epithelial integrin, alphavbeta6, regulates surfactant homeostasis in vivo by activating latent transforming growth factor (TGF)-beta. Adult mice lacking the beta-subunit of alphavbeta6 (Itgb6-/-) developed increased bronchoalveolar lavage phospholipids and surfactant proteins A and D, and demonstrated abnormal-appearing alveolar macrophages, reminiscent of the human disease pulmonary alveolar proteinosis. Using lung-specific expression of constitutively active TGF-beta1 in Itgb6-/- mice, we found that TGF-beta1 was sufficient to normalize these abnormalities. Tgfbeta1-deficient mice also demonstrated increased phospholipids and surfactant proteins A and D, but mice lacking the key TGF-beta signaling molecule, SMAD3, did not. Therefore, integrin-mediated activation of latent TGF-beta1 regulates surfactant constituents independent of intracellular SMAD3. In vivo increases in surfactant protein A and D were not associated with increases in mRNA for these proteins in alveolar tissue from Itgb6-/- mice. On the other hand, isolated alveolar macrophages from Itgb6-/- mice were defective in processing phospholipids in vitro, suggesting that reduced surfactant clearance contributes to altered surfactant homeostasis in these mice in vivo. These findings show that alphavbeta6 and TGF-beta1 regulate homeostasis of phospholipids and collectins in adult mouse lungs and may have implications for anti-fibrotic therapeutics that inhibit active TGF-beta in the lung.