Objective: Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is a new method for the diagnosis and staging of lung disease, and its use is increasing worldwide. It has been used as a means of diagnosing lung cancer in its initial stages, and there are data supporting its use for the diagnosis of benign lung disease. The aim of this study was to share our experience with EBUS-TBNA and discuss its diagnostic value. Methods: We retrospectively analyzed the results related to 159 patients who underwent EBUS-TBNA at our pulmonary medicine clinic between 2010 and 2013. We recorded the location and size of lymph nodes seen during EBUS. Lymph nodes that appeared to be affected on EBUS were sampled at least twice. We recorded the diagnostic results of EBUS-TBNA and (for cases in which EBUS-TBNA yielded an inconclusive diagnosis) the final diagnoses after further investigation and follow-up. Results: We evaluated 159 patients, of whom 89 (56%) were male and 70 (44%) were female. The mean age was 54.6 ± 14.2 years among the male patients and 51.9 ± 11.3 years among the female patients. Of the 159 patients evaluated, 115 (84%) were correctly diagnosed by EBUS. The diagnostic accuracy of EBUS-TBNA was 83% for benign granulomatous diseases and 77% for malignant diseases. Conclusions: The diagnostic value of EBUS-TBNA is also high for benign pathologies, such as sarcoidosis and tuberculosis. In patients with mediastinal disorders, the use of EBUS-TBNA should be encouraged, primarily because it markedly reduces the need for mediastinoscopy.

Keywords: Sarcoidosis; Tuberculosis, pulmonary; Lung neoplasms; Bronchoscopy; Mediastinoscopy; Endosonography.

Objective: Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is a minimally invasive diagnostic test with a high diagnostic yield for suspicious central pulmonary lesions and for mediastinal lymph node staging. The main objective of this study was to describe the diagnostic yield of EBUS-TBNA for mediastinal lymph node staging in patients with suspected lung cancer. Methods: Prospective study of patients undergoing EBUS-TBNA for diagnosis. Patients ≥ 18 years of age were recruited between July of 2010 and August of 2013. We recorded demographic variables, radiological characteristics provided by axial CT of the chest, location of the lesion in the mediastinum as per the International Association for the Study of Lung Cancer classification, and definitive diagnostic result (EBUS with a diagnostic biopsy or a definitive diagnostic method). Results: Our analysis included 354 biopsies, from 145 patients. Of those 145 patients, 54.48% were male. The mean age was 63.75 years. The mean lymph node size was 15.03 mm, and 90 lymph nodes were smaller than 10.0 mm. The EBUS-TBNA method showed a sensitivity of 91.17%, a specificity of 100.0%, and a negative predictive value of 92.9%. The most common histological diagnosis was adenocarcinoma. Conclusions: EBUS-TBNA is a diagnostic tool that yields satisfactory results in the staging of neoplastic mediastinal lesions.

Keywords: Lung neoplasms; Bronchoscopy; Endosonography; Neoplasm staging.

Objective: Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is a minimally invasive, safe and accurate method for collecting samples from mediastinal and hilar lymph nodes. This study focused on the initial results obtained with EBUS-TBNA for lung cancer and lymph node staging at three teaching hospitals in Brazil. Methods: This was a retrospective analysis of patients diagnosed with lung cancer and submitted to EBUS-TBNA for mediastinal lymph node staging. The EBUS-TBNA procedures, which involved the use of an EBUS scope, an ultrasound processor, and a compatible, disposable 22 G needle, were performed while the patients were under general anesthesia. Results: Between January of 2011 and January of 2014, 149 patients underwent EBUS-TBNA for lymph node staging. The mean age was 66 ± 12 years, and 58% were male. A total of 407 lymph nodes were sampled by EBUS-TBNA. The most common types of lung neoplasm were adenocarcinoma (in 67%) and squamous cell carcinoma (in 24%). For lung cancer staging, EBUS-TBNA was found to have a sensitivity of 96%, a specificity of 100%, and a negative predictive value of 85%. Conclusions: We found EBUS-TBNA to be a safe and accurate method for lymph node staging in lung cancer patients.

Keywords: Lung neoplasms; Neoplasm staging; Bronchoscopy; Endoscopic ultrasound-guided fine needle aspiration; Lymph nodes.

Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is a new method for the diagnosis and staging of mediastinal lymph nodes. The objective of this study was to evaluate the preliminary results obtained with EBUS-TBNA in the diagnosis of lesions and mediastinal lymph node staging. Methods: We evaluated patients with tumors or mediastinal adenopathy, diagnosed with or suspected of having lung cancer. The procedures were performed with the patients under sedation or under general anesthesia. Material was collected by EBUS-TBNA, after which it was prepared on slides, fixed in either absolute alcohol (for cytology) or formalin (for cell-block analysis). Results: We included 50 patients (30 males). The mean age was 58.3 ± 13.5 years. We performed 201 biopsies of 81 lymph nodes or mediastinal masses (mean of 2.5 punctures/biopsy). The quantity of material was considered sufficient for cytology in 37 patients (74%), 21 (57%) of whom were thus diagnosed with malignancy. Of the remaining 16 patients, 1 was diagnosed with tuberculosis, 6 entered clinical follow-up, and 9  underwent further investigation (2 diagnosed with neoplasm-false-negative results). The yield was higher when the procedure was performed for diagnostic purposes, as well as being higher in patients with lesions in multiple stations and in biopsies involving the subcarinal lymph node station. One patient had endobronchial bleeding, which was resolved with local measures. There were no deaths among the patients evaluated. Conclusions: This preliminary experience shows that EBUS-TBNA is a safe procedure. Our diagnostic yield, although lower than that reported in the literature, was consistent with the learning curve for the method.

Keywords: Ultrasonography, interventional; Biopsy, fine-needle; Neoplasm staging; Lung neoplasms; Bronchoscopy.

Background: Transbronchial needle aspiration (TBNA) with a flexible bronchoscope has been used for many years in the United States of America to diagnose bronchogenic carcinoma. However little information on the subject is available in Brazil. Objective: Assess the effectiveness of transbronchial needle aspiration for diagnosis and staging of lung cancer. Method: A retrospective review was made of 74 TBNA performed at the National Cancer Institute, in Rio de Janeiro, Brazil. a thoracic computerized tomography had oreviouslbeen made of all patients. Eleven (15%) patients exhibited mediastinal masses and 63 (85%) hilar masses. Seventy six endoscopic alterations were detected: enlargement of the main carina in 44 (59%) patients; enlargement of the secondary carina in 12 (16%); paratracheal compression in 5 (7%); posterior tracheal wall compression in 3 (4%); main bronchus compression in 5 (7%) AND BRONCHOSCOPY was normal in 5 (7%) patients. Results: Specimens were satisfactory for diagnosis in 42 (57%) patients and in 34 (46%) diagnosis was confirmed. Malignancy was confirmed in 30 of 34 patients (88%): as follows: small cell undifferentiated carcinoma in 10 of 30 (33%); squamous cell lung cancer in 7 of 30 (23%); adenocarcinoma 7 of 30 (23%); and non-small cell lung cancer in 6 of 30 (20%). Four of 30 (12%) were diagnosed as bearers of benign disease: tuberculosis 2 of 4 (50%) and sarcoidosis 2 of 4 (50%). No complications related to the method were perceived. Conclusion: This preliminary experience with TBNA in 74 patients indicated that this method is safe, easy to perform with a minimum of complications and useful for the diagnosis and staging of pulmonary neoplasms.

Keywords: Bronchoscopy/methods. Carcinoma, bronchogenic/diagnosis. Aspiration/methods.

Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) has played a key role in the diagnosis of mediastinal, paratracheal, and peribronchial lesions, as well as in lymph node staging for lung cancer. Despite its minimally invasive character, EBUS-TBNA has demonstrated a diagnostic yield comparable with that of established surgical methods. It has therefore gained credibility and has become a routine procedure at various referral centers. A successful EBUS-TBNA procedure requires careful planning, which includes a thorough review of the radiological imaging and special care during specimen collection and preparation, as well as technical expertise, experience with the procedure itself, and knowledge of the potential complications inherent to the procedure. The most common indications for EBUS-TBNA include lymph node staging for lung cancer and the diagnostic investigation of mediastinal/hilar masses and lymph node enlargement. Recently, tumor biomarkers in malignant samples collected during the EBUS-TBNA procedure have begun to be identified, and this molecular analysis has proven to be absolutely feasible. The EBUS-TBNA procedure has yet to be included on the Brazilian Medical Association list of medical procedures approved for reimbursement. The EBUS-TBNA procedure has shown to be a safe and accurate tool for lung cancer staging/restaging, as well as for the diagnosis of mediastinal, paratracheal, and peribronchial lesions/lymph node enlargement.

Objectives: The advent of massively parallel next-generation sequencing (MP-NGS) offers potential advantages over sequential molecular profiling (SMP) in the management of non-small cell lung cancer (NSCLC). This study compares the two methodologies using samples obtained through endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA), focusing on actionable mutation detection, turnaround time (TAT), and clinical outcomes. Methods: A retrospective analysis was conducted on NSCLC patients who underwent EBUS-TBNA and molecular characterization between January 2020 and December 2023. SMP and MP-NGS were compared in terms of actionable mutation detection rates, TAT, and impact on overall survival (OS). Results: Among 106 patients, MP-NGS demonstrated a significantly higher detection rate of actionable mutations compared to SMP (40.9% vs. 22.2%, p=0.042). The median TAT was slightly shorter with SMP than with externally outsourced MP-NGS (17 days vs. 23 days, p=0.076). Patients diagnosed via MP-NGS were more frequently allocated to targeted therapies (44.26% vs. 22.2%, p=0.038), which may have positively influenced overall survival (672 days vs. 138 days, p=0.053). Conclusion: MP-NGS provided superior diagnostic and clinical advantages over SMP in NSCLC, supporting its adoption as a standard diagnostic approach to enhance personalized therapy and improve patient outcomes.

Keywords: Non-Small Cell Lung Cancer, Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration, Sequential Molecular Profiling, Massively Parallel Next-Generation Sequencing, Actionable Mutations, Personalized Therap

Objective: To determine the diagnostic yield of endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) in non-neoplastic patients with isolated intrathoracic lymphadenopathy (IL). Methods: This was a retrospective study of patients with isolated IL referred for EBUS-TBNA. We calculated the sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) of EBUS-TBNA in the diagnosis of granulomatous, reactive, and neoplastic lymphadenopathy. In cases of nonspecific granulomas, reactive lymphadenopathy, or inconclusive results, a definitive diagnosis was established by other diagnostic procedures or during a follow-up period of at least 18 months. Results: Among the 58 patients included in the study, EBUS-TBNA established a diagnosis of granulomatous disease in 22 (38%), reactive lymphadenopathy in 15 (26%), cancer in 8 (14%), and other diseases in 3 (5%). Results were inconclusive in 10 (17%), the diagnosis being established by other bronchoscopic procedures in 2 (20%) and by surgical procedures in 8 (80%). A final diagnosis of reactive lymphadenopathy was established in 12. Of those, 11 (92%) had their diagnosis confirmed during follow-up and 1 (8%) had their diagnosis confirmed by mediastinoscopy. In another 3, a final diagnosis of sarcoidosis or neoplasm was established. For the diagnosis of granulomatous disease, neoplasms, and reactive lymphadenopathy, EBUS-TBNA was found to have a sensitivity of 73%, 68%, and 92%, respectively; a specificity of 100%, 100%, and 93%, respectively; an accuracy of 86%, 93%, and 93%, respectively; a PPV of 100%, 100%, and 80%, respectively; and an NPV of 78%, 92%, and 98%, respectively. Conclusions: In non-neoplastic patients, granulomatous disease and reactive lymphadenopathy appear to be common causes of isolated IL. EBUS-TBNA shows promising results as a first-line minimally invasive diagnostic procedure. The results obtained by EBUS-TBNA can be optimized by examining clinical and radiological findings during follow-up or by comparison with the results obtained with other bronchoscopic methods.

Keywords: Endoscopic ultrasound-guided fine needle aspiration; Lymphadenopathy/diagnosis; Neoplasms.

Objective: To investigate the diagnostic value of α-enolase (ENO1) and serum ENO1 autoantibody levels in lung cancer. Methods: Immunohistochemistry staining and ELISA were performed to detect ENO1 expression in lung tissue and serum ENO1 autoantibody levels, respectively. Results: The expression of ENO1 was higher in lung cancer tissues than in benign lung disease tissues (p < 0.001). The proportion of lung cancer samples expressing ENO1 was not significantly different among the various pathological classification groups. The proportion of samples expressing ENO1 was higher in lung cancer patients in stages I/II than in those in stages III/IV (χ2 = 5.445; p = 0.018). The expression of ENO1 in lung cancer tissues was not associated with age, gender, or smoking history. Serum ENO1 antibody levels were significantly higher in the lung cancer group than in the benign lung disease and control groups (p < 0.001). The differences among the pathological classification groups were not statistically significant. Serum ENO1 antibody levels were also in lung cancer patients in stages I/II than in those in stages III/IV (p < 0.01). Serum ENO1 antibody levels were not associated with age, gender, or smoking history in lung cancer patients. The ROC curve representing the diagnosis of lung cancer based on ENO1 antibody levels had an area under the curve of 0.806. Conclusions: Our results suggest that high levels of ENO1 are associated with the clinical stage of lung cancer and that ENO1 expression and its serum autoantibody levels show diagnostic value in lung cancer.

Keywords: Phosphopyruvate hydratase/analysis; Enzyme-linked immunosorbent assay; Immunohistochemistry; Lung neoplasms.

Many conditions result in chronic interstitial lung disease (ILD), being classified as fibrosing ILDs, including idiopathic pulmonary fibrosis, connective tissue diseases, sarcoidosis, and fibrotic hypersensitivity pneumonitis. HRCT plays an important role in the clinical evaluation of fibrosing ILDs. Current treatment perspectives are encouraging and reinforce the need for HRCT scans of adequate technical quality for early detection of fibrosing ILD. Despite efforts in this regard, the significance and management of imaging findings of early interstitial lung abnormalities have yet to be clarified. After identification of CT findings consistent with fibrosing ILD, radiologists must be able to identify characteristic morphological patterns and, in some cases, features of specific clinical entities. In cases in which HRCT features are not sufficiently specific for a definitive diagnosis, HRCT can aid in selecting the best site for surgical lung biopsy. CT follow-up is useful for identifying progressive fibrosing ILDs and detecting complications unrelated to the underlying disease, including infections, acute exacerbations, and neoplasms. Automated quantification tools have clinical applicability and are likely to be available for use in imaging analysis in the near future. In addition, incorporation of CT evaluation into scoring systems based on clinical and functional parameters for staging fibrosing disease is likely to become valuable in determining prognosis. Knowledge of the clinical applications of CT evaluation is essential for specialists managing patients with fibrosing ILD and can have a positive impact on the clinical course of the disease.

Keywords: Tomography, X-ray computed; Diagnostic imaging; Pulmonary fibrosis.

A significant percentage of pleural effusions remains without a diagnostic explanation. In such circumstances, the anatomical-pathological result of nonspecific chronic pleuritis should be revised. This is an important issue, not only for the pathologist, but mainly for the pneumologist, who usually makes the clinical-pathological correlation during the routine practice. Although the existence of established criteria is accepted, they are certainly subjective and make the communication by means of a common language difficult, mainly among pathologists. The authors recently studied 311 pleural biopsies with histo-pathological diagnoses of chronic nonspecific pleuritis. All specimens were reviewed and the histo-pathological parameters quantified by stereology. The patients were stratified according to the final diagnosis of their disease, including cases of chronic renal failure, vasculitis, pancreatitis, tuberculosis, cancer, and congestive cardiac failure, in this case considering the pleura as normal. This procedure allowed us to obtain a discriminating model, whose morphological subcriteria classified almost 90% of the nonspecific chronic pleuritis biopsies, according to their final clinical diagnoses, which included true nonspecific chronic pleuritis or tuberculosis pleuritis, paraneoplastic pleuritis, or even normal pleura. By adding to this model the biochemistry or differential cytology of the pleural liquid, its classificatory power reaches 99% of correctness. This study represents the result of the experience acquired over several years in the histo-pathological interpretation of pleural biopsies, based on the correlation between morphology and biochemistry and cytology of the pleural fluid.

Keywords: Biopsy, needle. Pleura/pathology. Pleura/cytology. Pleural effusion.

Bronchoscopy with bronchoalveolar lavage, bronchial brush, and transbronchial biopsy are useful methods for the diagnosis of pulmonary diseases in patients infected with the human immunodeficiency virus (HIV). However, data on the accuracy of these techniques are conflicting. In order to estimate the sensitivity of the bronchoalveolar lavage, bronchial and transbronchial biopsy in pulmonary disease diagnosis in patients infected with HIV, the authors studied 71 consecutive patients, most of them with respiratory symptoms up to 15 days (58%) and radiologic signs of interstitial infiltrates (62%). The sensitivity was calculated taking as reference a constructed gold-standard, represented by the sum of all three techniques combined. Sensitivities for bronchoalveolar lavage, transbronchial biopsy, and bronchial brush were 86%, 43% and 5%, respectively. The association of bronchoalveolar lavage and transbronchial biopsy reached the sensitivity to 100%, reflecting how the gold-standard was constructed. The complication rate of the procedures was 3%. These results suggest that, in this population: (1) bronchoscopy with bronchoalveolar lavage, bronchial brush, and transbronchial biopsy are secure procedures with good diagnostic performance; (2) bronchoalveolar lavage alone has reached the highest sensitivity, whereas both bronchoalveolar lavage and transbronchial biopsy can be considered complementary techniques; (3) the association of bronchoalveolar lavage and transbronchial biopsy performed better than bronchoalveolar lavage alone; and (4) the use of bronchial brush in the sequence used in this protocol did not have any influence on the performance of diagnosis.

Keywords: Human immunodeficiency virus. Lung diseases. Diagnostic techniques. HIV. Lung infections.

Objective: To evaluate the diagnostic performance of the rapid shallow breathing index (RSBI) in predicting extubation failure among adult patients in the intensive care unit and to determine the appropriateness of the classical RSBI cut-off value. Methods: This was a prospective study conducted in the adult intensive care unit of the Botucatu School of Medicine Hospital das Clínicas. The RSBI was evaluated in 73 consecutive patients considered clinically ready for extubation. Results: The classical RSBI cut-off value (105 breaths/min/L) presented a sensitivity of 20% and a specificity of 95% (sum = 115%). Analysis of the receiver operator characteristic (ROC) curve revealed a better cut-off value (76.5 breaths/min/L), which presented a sensitivity of 66% and a specificity of 74% (sum = 140%). The area under the ROC curve for the RSBI was 0.78. Conclusions: The classical RSBI cut-off value proved inappropriate, predicting only 20% of the cases of extubation failure in our sample. The new cut-off value provided substantial improvement in sensitivity, with an acceptable loss of specificity. The area under the ROC curve indicated that the discriminative power of the RSBI is satisfactory, which justifies the validation of this index for use.

Keywords: Adult; Intensive care; ROC curve; Ventilator weaning; Diagnosis; Respiration, artificial.

Objective: To determine the proportional distribution of endobronchial tuberculosis (EBTB) subtypes and to evaluate the types of bronchoscopic diagnostic procedures that can prove granulomatous inflammation. Methods: This was a retrospective study of 18 HIV-negative patients with biopsy-proven EBTB treated between 2010 and 2014. Results: The most common EBTB subtypes, as classified by the bronchoscopic features, were tumorous and granular (in 22.2% for both). Sputum smear microscopy was performed in 11 patients and was positive for AFB in 4 (36.3%). Sputum culture was also performed in 11 patients and was positive for Mycobacterium tuberculosis in 10 (90.9%). Smear microscopy of BAL fluid (BALF) was performed in 16 patients and was positive for AFB in 10 (62.5%). Culture of BALF was also performed in 16 patients and was positive for M. tuberculosis in 15 (93.7%). Culture of BALF was positive for M. tuberculosis in 93.7% of the 16 patients tested. Among the 18 patients with EBTB, granulomatous inflammation was proven by the following bronchoscopic diagnostic procedures: bronchial mucosal biopsy, in 8 (44.4%); bronchial brushing, in 7 (38.8%); fine-needle aspiration biopsy, in 2 (11.1%); and BAL, in 2 (11.1%). Bronchial anthracofibrosis was observed in 5 (27.7%) of the 18 cases evaluated. Conclusions: In our sample of EBTB patients, the most common subtypes were the tumorous and granular subtypes. We recommend that sputum samples and BALF samples be evaluated by smear microscopy for AFB and by culture for M. tuberculosis, which could increase the rates of early diagnosis of EBTB. We also recommend that bronchial brushing be employed together with other bronchoscopic diagnostic procedures in patients suspected of having EBTB.

Keywords: Tuberculosis, pulmonary; Mycobacterium tuberculosis; Diagnostic techniques and procedures; Bronchoscopy.

Objective: To study the clinical, radiological, and histopathological patterns of transbronchial biopsy (TBB) used in order to confirm the diagnosis in patients with clinical suspicion of interstitial lung disease (ILD) treated at a tertiary-care university hospital. Methods: We reviewed the medical records, radiology reports, and reports of transbronchial biopsies from all patients with suspected ILD who underwent TBB between January of 1999 and December of 2006 at the Hospital das Clínicas de Botucatu, located in the city of Botucatu, Brazil. Results: The study included 56 patients. Of those, 11 (19.6%) had a definitive diagnosis of idiopathic pulmonary fibrosis (IPF), the rate of which was significantly higher in the patients in which ILD was a possible diagnosis in comparison with those in which ILD was the prime suspect (p = 0.011), demonstrating the contribution of TBB to the diagnostic confirmation of these diseases. The histopathological examination of the biopsies revealed that 27.3% of the patients with IPF showed a pattern of organizing pneumonia, which suggests greater disease severity. The most common histological pattern was the indeterminate pattern, reflecting the peripheral characteristic of IPF. However, the fibrosis pattern showed high specificity and high negative predictive value. For CT scan patterns suggestive of IPF, the ROC curve showed that the best relationship between sensitivity and specificity occurred when five radiological alterations were present. Honeycombing was found to be strongly suggestive of IPF (p = 0.01). Conclusions: For ILDs, chest CT should always be performed, and TBB should be used in specific situations, according to the suspicion and distribution of lesions.

Keywords: Lung diseases, interstitial; Diagnosis, differential; Bronchoscopy.

Macrolides are drugs that have antimicrobial effects, especially against intracellular pathogens. Various studies have shown that macrolides might also have anti-inflammatory effects. Macrolides inhibit the production of interleukins and can reduce pulmonary neutrophilic inflammation. Clinical trials have demonstrated beneficial effects of macrolides in various chronic lung diseases. The objective of this study was to review recent data in the medical literature on the anti-inflammatory effects of macrolides in childhood lung diseases by searching the Medline (PubMed) database. We used the following search terms: "macrolide and cystic fibrosis"; "macrolide and asthma"; "macrolide and bronchiolitis obliterans"; and "macrolide and acute bronchiolitis". We selected articles published in international scientific journals between 2001 and 2012. Clinical studies and in vitro evidence have confirmed the anti-inflammatory effect of macrolides in respiratory diseases. Some clinical trials have shown the benefits of the administration of macrolides in patients with cystic fibrosis, although the risk of bacterial resistance should be considered in the analysis of those benefits. Such benefits are controversial in other respiratory diseases, and the routine use of macrolides is not recommended. Further controlled clinical trials are required in order to assess the efficacy of macrolides as anti-inflammatory drugs, so that the benefits in the treatment of each specific clinical condition can be better established.

Keywords: Macrolides; Asthma; Cystic Fibrosis; Bronchiolitis.

Objective: To assess the relative frequency of incident cases of interstitial lung diseases (ILDs) in Brazil. Methods: This was a retrospective survey of new cases of ILD in six referral centers between January of 2013 and January of 2020. The diagnosis of ILD followed the criteria suggested by international bodies or was made through multidisciplinary discussion (MDD). The condition was characterized as unclassifiable ILD when there was no specific final diagnosis following MDD or when there was disagreement between clinical, radiological, or histological data. Results: The sample comprised 1,406 patients (mean age = 61 ± 14 years), and 764 (54%) were female. Of the 747 cases exposed to hypersensitivity pneumonitis (HP)-related antigens, 327 (44%) had a final diagnosis of HP. A family history of ILD was reported in 8% of cases. HRCT findings were indicative of fibrosis in 74% of cases, including honeycombing, in 21%. Relevant autoantibodies were detected in 33% of cases. Transbronchial biopsy was performed in 23% of patients, and surgical lung biopsy, in 17%. The final diagnoses were: connective tissue disease-associated ILD (in 27%), HP (in 23%), idiopathic pulmonary fibrosis (in 14%), unclassifiable ILD (in 10%), and sarcoidosis (in 6%). Diagnoses varied significantly among centers (?2 = 312.4; p < 0.001). Conclusions: Our findings show that connective tissue disease-associated ILD is the most common ILD in Brazil, followed by HP. These results highlight the need for close collaboration between pulmonologists and rheumatologists, the importance of detailed questioning of patients in regard with potential exposure to antigens, and the need for public health campaigns to stress the importance of avoiding such exposure.

Keywords: Lung diseases, interstitial/epidemiology; Alveolitis, extrinsic allergic/epidemiology; Connective tissue diseases/epidemiology, Sarcoidosis/epidemiology; Idiopathic pulmonary fibrosis/epidemiology