{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,11,1]],"date-time":"2026-11-01T11:41:43Z","timestamp":1793533303273,"version":"4.5.0"},"reference-count":15,"publisher":"BMJ","content-domain":{"domain":["bmj.com"],"crossmark-restriction":true},"short-container-title":["BMJ Case Reports"],"accepted":{"date-parts":[[2018,9,25]]},"abstract":"<jats:p>The flow\u2013volume loop (FVL) analysis is typically helpful in establishing the diagnosis of airway obstruction caused by endobronchial lesions. In this report, we describe a patient with emphysema and tobacco abuse who presented with chronic dry cough and severe chronic obstructive pulmonary disease (COPD) refractory to standard therapy. The initial FVL showed a relatively normal forced expiratory peak flow shape followed by a smooth flattening of the expiratory curve on spirometry, a pattern consistent with distal airway obstruction as seen in severe asthma or COPD. The patient was later found to have a large endotracheal mass. This atypical presentation, along with the unusual FVL, led to a significant delay in the diagnosis of the tracheal mass. A high level of suspicion is needed to diagnose variable intrathoracic airway obstruction in patients presenting with severe asthma or COPD who fail to improve with standard therapy.<\/jats:p>","DOI":"10.1136\/bcr-2018-226430","type":"journal-article","created":{"date-parts":[[2018,10,13]],"date-time":"2018-10-13T01:45:31Z","timestamp":1539395131000},"page":"bcr-2018-226430","update-policy":"https:\/\/doi.org\/10.1136\/crossmarkpolicy","source":"Crossref","is-referenced-by-count":3,"title":["Large endotracheal tumour presenting as severe COPD: flow\u2013volume loop analysis, not always a straightforward diagnostic test"],"prefix":"10.1136","volume":"2018","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-0498-6896","authenticated-orcid":false,"given":"Iliya P","family":"Amaza","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Swan","family":"Lee","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rolando","family":"Sanchez","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"239","published-online":{"date-parts":[[2018,10,12]]},"reference":[{"key":"2025042706320537000_2018.oct12_1.bcr-2018-226430.1","doi-asserted-by":"publisher","DOI":"10.1183\/09031936.05.00035205"},{"key":"2025042706320537000_2018.oct12_1.bcr-2018-226430.2","doi-asserted-by":"publisher","DOI":"10.1016\/j.otc.2013.10.002"},{"key":"2025042706320537000_2018.oct12_1.bcr-2018-226430.3","doi-asserted-by":"crossref","first-page":"461","DOI":"10.4187\/respcare.09540461","article-title":"Inspiratory flow-volume curve evaluation for detecting upper airway disease","volume":"54","author":"Sterner","year":"2009","journal-title":"Respir Care"},{"key":"2025042706320537000_2018.oct12_1.bcr-2018-226430.4","doi-asserted-by":"crossref","first-page":"3781","DOI":"10.21037\/jtd.2016.12.67","article-title":"Tracheal and bronchial tumors","volume":"8","author":"Varela","year":"2016","journal-title":"J Thorac Dis"},{"key":"2025042706320537000_2018.oct12_1.bcr-2018-226430.5","doi-asserted-by":"publisher","DOI":"10.1002\/cncr.20866"},{"key":"2025042706320537000_2018.oct12_1.bcr-2018-226430.6","doi-asserted-by":"publisher","DOI":"10.1002\/ijc.28625"},{"key":"2025042706320537000_2018.oct12_1.bcr-2018-226430.7","first-page":"85","article-title":"[Melanoma metastatic to the trachea and nasal cavity: description of a case and review of the literature]","volume":"11","author":"Nicolai","year":"1991","journal-title":"Acta Otorhinolaryngol Ital"},{"key":"2025042706320537000_2018.oct12_1.bcr-2018-226430.8","doi-asserted-by":"crossref","first-page":"253","DOI":"10.12659\/AJCR.889291","article-title":"Endobronchial metastasis from primary anorectal melanoma","volume":"14","author":"Heyman","year":"2013","journal-title":"Am J Case Rep"},{"key":"2025042706320537000_2018.oct12_1.bcr-2018-226430.9","doi-asserted-by":"publisher","DOI":"10.1002\/lary.24436"},{"key":"2025042706320537000_2018.oct12_1.bcr-2018-226430.10","doi-asserted-by":"publisher","DOI":"10.1016\/j.lungcan.2014.03.005"},{"key":"2025042706320537000_2018.oct12_1.bcr-2018-226430.11","doi-asserted-by":"crossref","first-page":"448","DOI":"10.4187\/respcare.09540448","article-title":"The inspiratory flow-volume curve: the neglected child of pulmonary diagnostics","volume":"54","author":"Ruppel","year":"2009","journal-title":"Respir Care"},{"key":"2025042706320537000_2018.oct12_1.bcr-2018-226430.12","doi-asserted-by":"crossref","first-page":"474","DOI":"10.4187\/respcare.09540474","article-title":"Detection of upper airway obstruction with spirometry results and the flow-volume loop: a comparison of quantitative and visual inspection criteria","volume":"54","author":"Modrykamien","year":"2009","journal-title":"Respir Care"},{"key":"2025042706320537000_2018.oct12_1.bcr-2018-226430.13","doi-asserted-by":"crossref","first-page":"1286","DOI":"10.1016\/S0022-5223(96)70234-9","article-title":"Upper airway obstruction caused by low-grade tracheal papillary adenocarcinoma: an usual flow-volume loop pattern","volume":"111","author":"Clarke","year":"1996","journal-title":"J Thorac Cardiovasc Surg"},{"key":"2025042706320537000_2018.oct12_1.bcr-2018-226430.14","first-page":"107","article-title":"Asthma or not? 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