Kuranishi et al. Respiratory Research (2015) 16:55 DOI 10.1186/s12931-015-0213-7 RESEARCH Open Access Airway-centered interstitial fibrosis: etiology, clinical findings and prognosis Lilian Tiemi Kuranishi1*, Kevin O Leslie2, Rimarcs Gomes Ferreira3, Ester Aparecida Ney Coletta3, Karin Mueller Storrer1, Maria Raquel Soares1 and Carlos Alberto de Castro Pereira1 Abstract Background: Airway-centered Interstitial Fibrosis (ACIF) is a common pathologic pattern observed in our practice. Objectives: Theobjectivesofthisstudyaretodescribethecausesassociated with ACIF in a large sample of patients and its effect on survival. Methods: A retrospective study in three centers of interstitial lung disease in São Paulo, between January of 1995 and December of 2012. The surgical lung biopsy specimens were reviewed by three pathologists. The clinical, functional and tomographic findings were analyzed by a standardized protocol. Results: Therewere68casesofACIF,mostofthemwomen.Themeanagewas57±12yr.Dyspnea,cough,restrictive pattern at spirometry and oxygen desaturation at exercise were common. A reticular pattern with peribronchovascular infiltrates was found in 79% of the cases. The etiologies of ACIF were hypersensitivity pneumonitis in 29 (42.6%), gastroesophageal reflux disease in 17 (25.0%), collagen vascular disease in 4 (5.9%), a combination of them in 15 cases and idiopathic in 3 (4.4%). The median survival was 116 months (95% CI = 58.5 – 173.5). Lower values of oxygen saturation at rest, presence of cough and some histological findings - organizing tissue in the airways, fibroblastic foci and microscopic honeycombing - were predictors of worse survival. Conclusions: ACIF is an interstitial lung disease with a better survival when compared with IPF. The main etiologies are HPandGERD.Theoxygensaturationatrest,thepresenceof cough and some histological findings are predictors of survival. Keywords: Interstitial lung disease, Hypersensitivity pneumonia, Gastroesophageal reflux, Pulmonary fibrosis Introduction findings have been described in hypersensitivity pneumon- Since 2002 a new interstitial pneumonia centered on small itis (HP) [8-15] or be secondary to gastroesophageal reflux airways and no granulomas has been described in small disease (GERD), isolated or associated with connective tis- series [1-4]. This entity has been variably called centrilobu- sue diseases [16,17]. In our clinical practice this pathologic lar fibrosis, bronchiolocentric interstitial pneumonia, patterniscommoninmultidisciplinarycasediscussions. airway-centered interstitial fibrosis, and peribronchiolar The objectives of the present study were to describe metaplasia [3-6]. Lung biopsies from these cases showed a the causes, the clinical, tomographic, functional and distinctive pattern of interstitial fibrosis centered and ex- pathologic findings and their influence on survival in a tending around the bronchioles, often with bronchiolar large number of patients with histologic diagnosis of metaplasia of the epithelium. Due to involvement of small airway-centered interstitial fibrosis. as well large airways [5,7], the best name seems to be airway-centered interstitial fibrosis (ACIF). The prognosis is Material and methods unknown due to small number of cases described [2-4]. Selection of cases The etiology in these series was unclear. Similar pathologic A retrospective cohort of 68 adult patients with ACIF was evaluated. The medical records of 2716 patients * Correspondence: [email protected] 1Pulmonary Department, Federal University of São Paulo, Sao Paulo, Brazil with interstitial lung diseases, seen between January of Full list of author information is available at the end of the article 1995 and December of 2012 at three facilities in the city © 2015 Kuranishi et al.; licensee BioMed Central. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. Kuranishi et al. Respiratory Research (2015) 16:55 Page 2 of 8 of São Paulo, Brazil, were reviewed. From this register related to environmental exposures were recorded. A 600 patients were submitted to surgical lung biopsies. diagnosis of HP was based on the exposure and the ab- Cases with any findings of possible ACIF or describing sence of other potential causes of ACIF. Precipitins tests bronchiolar involvement without a specific diagnosis of and cellular analysis of bronchoalveolar lavage were not bronchiolitis were reevaluated. In this database, 115 pa- available. Possible connective tissue disease (CTD) was tients had a diagnosis of possible ACIF by surgical lung investigated by clinical and complementary tests in all biopsy. From this sample, 36 cases were excluded due to cases. The diagnostic criteria for CTD were those previ- a another diagnosis after a review of the slides (mainly ously described [19]. bronchiolitis, characterized by bronchiolar inflammation Symptoms of GERD (heartburn, regurgitation) were and/or fibrosis in the absence of peribronchiolar involve- recorded in all cases. An ambulatory 24-hour esophageal ment as well absence of reticular pattern on HRCT); six pH measurement with a dual sensor was performed ac- cases were excluded due to incomplete data and five due cording to standardized techniques [20]. The diagnostic to honeycombing (an exclusion criteria due to possible criteria for an abnormal proximal [21] and distal [22] non representative biopsies in advanced disease) ob- reflux have been previously described. served on a HRCT scan. None of the patients died after After biopsies selection, the final clinical diagnoses were lung biopsy. Biopsies were done by small thoracotomies retrospectively determined by multidisciplinary discussion. or VATS, involving one or more sites, but this informa- The diagnoses were classified as HP, GERD, CTD, a com- tion was not available in final analysis. The final sample bination of two or more categories or idiopathic. comprised 68 patients. Pulmonary function tests were conducted according to This study was approved by ethics committee of the the American Thoracic Society guidelines [23]. The nor- Federal University of São Paulo (register number 2079-09). mal values for spirometry were recalculated according 2007 values derived for the Brazilian population [24]. Histological findings Normal values for DLco were from Crapo [25]. The per- Patients were selected primarily by a revision of lung ipheral oxygen saturation was evaluated at rest and after biopsies by two pathologists dedicated to lung pathology, a 4-minute self-paced step test [26]. and with a large experience in interstitial lung disease All CT scans were read by experienced radiologists (ILD). The cases were selected initially by one of them and pulmonologists through a systematic analysis of the and 48 of them were sent to KOL for confirmation. He findings. The final findings were selected by consensus. agreed with diagnoses and described and classified the Scores for extension of disease were not calculated. Ex- findings in each case. The remaining twenty cases were piratory views were not done systematically. diagnosed by consensus between our two pathologists, The drugs used for at least three months for ACIF and who also followed the same classification of findings. GERD treatment were recorded. Antigen avoidance and Concordance by kappa was not calculated. The diagnosis abatement procedures were recommended when expos- was based on previously suggested criteria [4-6]. The ure was present. main diagnostic criteria included a fibrosis predomin- antly bronchiolocentric associated with bronchiolar or Survival peribronchiolar inflammation and peribronchiolar meta- Survival was assessed from the day of the biopsy through plasia. Cases with granulomas and foreign material were December 2012. Deaths were identified by a follow-up con- excluded. Incidental findings like such as fibromyxoid tact or through telephone notification by relatives. Deaths tissue foci in airways, fibroblastic foci, honeycombing, were considered ACIF-related if they were due to respira- giant cells, cholesterol clefts, respiratory bronchiolitis, tory failure, pneumonia or pulmonary fibrosis. One patient features of acute injury (tissue edema and the presence was censored at the time of lung transplantation. of fibrin), and focal areas of heterogeneous or homoge- neous fibrosis (usual interstitial pneumonia (UIP) and nod-specific interstitial pneumonia (NSIP) like, respect- Statistical analysis ively) were recorded. All of the data analyses were performed using the SPSS program, version 19. According distribution, data were Clinical analysis and HRCT expressed as mean ± SD, or as median and range. The con- A standardized protocol for investigation of interstitial tinuous data with a normal distribution were compared lung diseases was used for all patients. Dyspnoea was using t-tests. A chi-square test was used for comparisons of assessed by Magnitude of Task of Basal Dyspnea Index proportions. The impact of clinical, functional, tomographic (BDI) [18]. Total BDI score was not considered because and pathologic data on survival was calculated by univariate functional impairment and magnitude of effort do not Cox