ICHIMURA Hideo

Kikuchi Kazunori

Ozawa Yuichiro

SATO Yukio

Shiigai Masanari

Shiotani Seiji

Surgical Case Reports

Tsukuba Repository  (Tulips-R)

Enlarged mediastinal air cyst in a patientwith bronchial diverticula localized in theleft main bronchus: a case report withsurgical and bronchoscopic findings著者 Ichimura Hideo, Ozawa Yuichiro, ShiigaiMasanari, Shiotani Seiji, Kikuchi Kazunori,Sato Yukiojournal orpublication titleSurgical Case Reportsvolume 3page range 1year 2017-01権利 (C) The Author(s). 2017 Open Access Thisarticle is distributed under the terms of theCreative Commons Attribution 4.0 InternationalLicense(http://creativecommons.org/licenses/by/4.0/),which permits unrestricted use, distribution,and reproduction in any medium, provided yougive appropriate credit to the originalauthor(s) and the source, provide a link tothe Creative Commons license, and indicate ifchanges were made.URL http://hdl.handle.net/2241/00145800doi: 10.1186/s40792-016-0282-yCreative Commons : 表示http://creativecommons.org/licenses/by/3.0/deed.jaCASE REPORT Open AccessEnlarged mediastinal air cyst in a patientwith bronchial diverticula localized in theleft main bronchus: a case report withsurgical and bronchoscopic findingsHideo Ichimura1,2* , Yuichiro Ozawa3, Masanari Shiigai4, Seiji Shiotani4, Kazunori Kikuchi5 and Yukio Sato1AbstractBackground: A mediastinal air cyst is a rare computed tomography (CT) finding. Once the lesion is identified, it isdifficult to diagnose and treat. Meanwhile, bronchial diverticula have been reported as a CT finding observed in certainpulmonary pathologic conditions. We encountered the case of an enlarged mediastinal air cyst accompanied withbronchial diverticula and upper lobe-dominant fibrous changes of the lung.Case presentation: A 69-year-old man with a chronic cough who had regularly visited a chest physician for upperlobe-dominant pulmonary fibrosis was referred to our hospital for the examination of an enlarged mediastinal air cyst.Chest CT exhibited an air cyst (size, 30 mm) connected to the lumen of the left main bronchus (LMB) and multiple tinyoutpouches only on the LMB. Flexible bronchoscopy showed bubbling from slits or indentations of the bronchial mucosaonly in the LMB but not in the right main bronchus or lobar bronchus. For therapeutic diagnosis, we removed the air cyst.Based on clinical, surgical, and pathological findings, we diagnosed the air cyst as an enlarged bronchial diverticulum.Conclusions: This is the first case wherein bronchoscopic and surgical findings of bronchial diverticula and an enlargedbronchial diverticulum are reported. There are possible pathogenic mechanisms in cases of pulmonary disease that areattributable to enlargement of the bronchial diverticula.Keywords: Bronchial diverticula, Mediastinal air cyst, Upper lobe-dominant pulmonary fibrosis, SurgeryBackgroundWhen we incidentally detect an air cyst in the mediasti-num, the lesion is left intact and monitored initially sinceit is presumed to be benign in nature. However, if thelesion exhibits an enlargement over time or if the patientdevelops symptoms, we proceed to diagnose the lesionand begin the treatment process. These processes may bechallenging since mediastinal air cysts rarely develop.Conversely, the detection of bronchial diverticula (BDs),and particularly those that are less than 5 mm in size, hasincreased with the recent development of multi-detectorrow computed tomography (MDCT) [1, 2]. BDs are alsorare findings and are not usually a pathologic condition;however, in some cases, therapeutic intervention may beconsidered. We present herein a case of an enlarged medi-astinal air cyst whose CT simultaneously showed BDs inonly the left main bronchus (LMB) as well as upper lobe-dominant pulmonary fibrosis. We performed surgery fortherapeutic diagnosis of an enlarged air cyst.Case presentationA 69-year-old man, who had regularly visited a chestphysician for upper lobe-dominant pulmonary fibrosisand chronic cough, was referred to our hospital for theexamination of an enlarged air-filled mediastinal cysticlesion detected using chest computed tomography (CT).The patient did not have any smoking history, worked atan iron cast manufacturing industry, and was prescribedantitussives for persistent cough by his physician. Inlaboratory studies upon admission, levels of white blood* Correspondence: ichimura@md.tsukuba.ac.jp1Department of Thoracic Surgery, Faculty of Medicine, University of Tsukuba,2-1-1 Jyounan, Hitachi, Ibaraki 317-0077, Japan2Department of Thoracic Surgery, Hitachi General Hospital, Hitachi, JapanFull list of author information is available at the end of the article© The Author(s). 2017 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, andreproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link tothe Creative Commons license, and indicate if changes were made.Ichimura et al. Surgical Case Reports  (2017) 3:1 DOI 10.1186/s40792-016-0282-ycells (4000/μL), lactate dehydrogenase (193 IU/L), C-re-active protein (0.04 mg/dL), and KL-6 (363 U/mL) werein the normal ranges. A pulmonary function test showedrestrictive ventilatory impairment (vital capacity (VC)2.16 L; %VC 60.7%; forced vital capacity (FVC) 2.33 L;forced expiratory volume in 1 s (FEV1) 2.25 L; FEV1/FVC 96.6%). CT showed a mediastinal air cyst (size30 mm) adjacent to the LMB and dominant fibrouschanges in the subpleural region in both upper lobes(Fig. 1a). A reconstructed frontal plane CT scan showedthat the lumen of the cystic lesion was connected to thatof the LMB through a thin tunnel, and that, many tinyair spaces extended from the LMB wall (Fig. 1c, d). Flex-ible bronchoscopy showed a round-shaped lumen of theLMB and bubbling from slits or indentations of thebronchial mucosa only in the LMB, but not in the rightmain bronchus or lobar bronchus (Fig. 2 and Additionalfile 1: Video 1). In comparison with the chest radio-graphs obtained during the first visit (Fig. 3a) and 4 yearsearlier (Fig. 3b), progression of volume loss in the rightupper lobe was apparent. Compared with CT obtained4 years earlier (Fig. 1b), the current CT (Fig. 1a) showedan enlargement of the air cyst over time.For therapeutic diagnosis, we performed a removal ofthe cystic lesion under mini-thoracotomy using an11-cm incision and two surgical ports (operative time230 min; volume of blood loss 170 mL; Fig. 4 andAdditional file 2: Video 2). Since it was difficult to identifythe cystic lesion in the subaortic region (where it shouldexist) and fibrotic change of the region was apparent, wefirst identified the left recurrent nerve to avoid anaccidental injury and subsequently attempted to dissectthe cystic lesion. When we unintentionally made a hole inthe wall of the lesion, we found the smooth, white-coloredcystic lumen that enabled us to recognize the extent of thelesion. We nearly removed the entire cystic lesion that didnot have adventitia. Since the cystic wall adjacent to theLMB could not be dissected due to its firm adhesion, anarea of approximately 1 × 0.5 cm of the LMB was left withretained lesion tissue. When we completed a dissection ofthe whole LMB circumferentially, we did not recognizesmall diverticula that appeared on the preoperative CT,which indicates that the diverticula remained intact in thebronchial sheath.Air leakage from the LMB was seen only at the sitewhere the cystic wall had not been dissected and wasstopped by placing a Z-suture using 4–0 PDS II(Ethicon, Inc., Somerville, NJ). To reinforce the suturesite and prevent another enlargement of tiny BDs, theFig. 1 a Computed tomography (CT) showing a mediastinal air cyst (arrow) and fibrotic changes in the subpleural region. b CT obtained 4 yearsbefore the first visit to our hospital showing a smaller air cyst (arrow). c CT in the frontal plane showing a connection between the cyst (Cy) andthe left main bronchus (LMB) (arrowhead). d CT in the frontal plane showing multiple extensions from the LMB (arrowheads)Fig. 2 Bronchoscopic image showing the left main bronchus. a Thereddish membranous portion is concave, thereby resulting in around-shaped lumen. b Bubbling from slits or indentations of thebronchial mucosa (arrow)Ichimura et al. Surgical Case Reports  (2017) 3:1 Page 2 of 4patient underwent circumferential covering of the wholeLMB with a polyglycolic acid (PGA) sheet. Finally, fibringlue was applied on the PGA sheet.The patient was discharged on postoperative day 11without any adverse events.Upon pathological examination, the inner membraneof the lesion was covered with ciliated bronchial epithe-lial cells. The wall of the lesion consisted of unstructuredfibrous tissue without bronchial gland tissue norcartilage (Fig. 5). Follow-up bronchoscopy was performed6 months postoperatively and indicated a disappearanceof the bubbling as well as the resolution of the chroniccough to that of pre-procedural levels. The antitussiveagent was discontinued postoperatively. Follow-up CTscans obtained at 1 year postoperatively showed no recur-rence of air space or further development of BDs.Thereafter, he was monitored and treated by his priorchest physician. He died of chronic respiratory failure dueto progression of upper lobe-dominant pulmonary fibrosis20 months after the surgery.DiscussionMediastinal air cysts in adults are extremely rare, andtheir differential diagnosis may include tracheocele (alsoknown as paratracheal air cyst or tracheal diverticulum)[3], bronchogenic cyst [4], and bronchopulmonary fore-gut duplication cyst [5]. On the basis of our case, werecommend that BD should be added to this list.The present case exhibited multiple tiny BDs in theLMB, and surgical findings confirmed the luminalconnection between the LMB and cystic lesion. Patho-logical examination of the cyst revealed bronchialepithelial lining. Therefore, we diagnosed the air cyst asan enlarged BD. Regarding the etiology of BDs, chronicinflammation resulting from various causes and in-creased intrabronchial pressure due to coughing wereassociated with the development of BDs [1, 2]. In ourcase, BDs were detected only in the LMB. Additionally,BD enlargement coincided with a volume reduction ofthe right upper lobe, which resulted from the progres-sion of upper lobe-dominant pulmonary fibrosis.Volume reduction of the right upper lobe resulted in thetracheal shift to the right that could induce the tractionon the LMB (shown in Fig. 3). When consideredtogether, we speculated that this mechanical traction ofthe LMB could be an initiating and/or an exacerbatingFig. 3 Chest radiograph taken at the a first visit and b 4 yearsbefore. The dotted line demarcates the left margin of the tracheaFig. 4 Intraoperative images showing a the opened lumen of the cystic lesion (arrow), b the resected specimen, c the placement of a Z-sutureon the undissected portion of the cystic lesion on the left main bronchus (LMB) (arrowheads), and d the LMB covered with a polyglycolicacid sheetIchimura et al. Surgical Case Reports  (2017) 3:1 Page 3 of 4factor of BDs. Furthermore, the absence of BDs in thetrachea and lobar bronchus and more peripheral airwaysupport the assumption that inhalation of particles orany underlying airway disease is less associated with theetiology of BDs in our case.With respect to surgical indication, resection of anenlarged air cyst communicating with the airway wouldbe warranted for pathological diagnosis and for eliminat-ing the risk of future possible infection. Since we specu-lated the above-mentioned etiology, we covered theLMB with a PGA sheet to prevent enlargement of otherBDs in the future. A 1-year postoperative workup usingbronchoscopy and MDCT indicated neither therecurrence of air space nor any adverse event. Althoughthe efficacy of this procedure is still inconclusive, we be-lieve this is an option for treating diseases attributable tothe mechanical vulnerability of the airway.ConclusionsThis is the first case wherein bronchoscopic andsurgical findings of bronchial diverticula and anenlarged bronchial diverticulum are reported. Mech-anical traction and vulnerability of the airway mighthave had a role in inducing an enlargement of an aircyst in this case.Additional filesAdditional file 1: Video 1. Bronchoscopy of the left main bronchusshowing bubbles from the slits or indentations of the mucosa(arrow). (7 MB)Additional file 2: Video 2. Intraoperative video showing removal of thecystic lesion and the circumferential coverage of the left main bronchuswith a polyglycolic acid sheet. (11 MB)AbbreviationsBD: Bronchial diverticula; CT: Computed tomography; LMB: Left mainbronchus; MDCT: Multi-detector row computed tomography;PGA: Polyglycolic acidFundingNone.Availability of data and materialsThe dataset supporting the conclusions of this case report is included withinthe article and supplementary files.Authors’ contributionsHI wrote the manuscript. HI and YO performed the surgery and cared thepatient. MS and SS read the chest computed tomography and chest X-ray.KK performed the pathological examination and obtained the microscopicphotographs. YS comprehensively supervised this case report. All authorsread and approved the final manuscript.Competing interestsThe authors declare that they have no competing interests.Consent for publicationSince the patient has passed away, written informed consent was obtainedfrom the patient’s spouse for publication of this case report andaccompanying images.Author details1Department of Thoracic Surgery, Faculty of Medicine, University of Tsukuba,2-1-1 Jyounan, Hitachi, Ibaraki 317-0077, Japan. 2Department of ThoracicSurgery, Hitachi General Hospital, Hitachi, Japan. 3Department of ThoracicSurgery, Tsukuba Medical Center Hospital, Tsukuba, Japan. 4Department ofRadiology, Tsukuba Medical Center Hospital, Tsukuba, Japan. 5Department ofPathology, Tsukuba Medical Center Hospital, Tsukuba, Japan.Received: 17 September 2016 Accepted: 20 December 2016References1. Sverzellati N, Ingegnoli A, Calabro E, Randi G, La Vecchia C, Marchianò A, etal. Bronchial diverticula in smokers on thin-section CT. Eur Radiol.2010;20:88–94.2. Miyara T, Oshiro Y, Yamashiro T, Kamiya H, Ogawa K, Murayama S. Bronchialdiverticula detected by multidetector-row computed tomography:incidence and clinical features. J Thorac Imaging. 2011;26:204–8.3. Endo S, Saito N, Hasegawa T, Sato Y, Sohara Y. Tracheocele: surgical andthoracoscopic findings. Ann Thorac Surg. 2005;79:686–7.4. Sundaramoorthi T, Mahadevan R, Nedumaran K, Jayaraman S, VaidyanathanKR. Intrabronchial rupture of bronchogenic cyst. Ann Thorac Surg. 2009;87:1919–20.5. Woodring JH, Vandiviere HM, Dillon ML. Air-filled, multilocular,bronchopulmonary foregut duplication cyst of the mediastinum. Unusualcomputed tomography appearance. Clin Imaging. 1989;13:44–7.Submit your manuscript to a journal and beneﬁ t from:7 Convenient online submission7 Rigorous peer review7 Immediate publication on acceptance7 Open access: articles freely available online7 High visibility within the ﬁ eld7 Retaining the copyright to your article    Submit your next manuscript at 7 springeropen.comFig. 5 Pathological images of the resected cystic lesion. a Grossappearance indicating that the cystic wall consists of unstructuredfibrous tissue without bronchial gland nor cartilage. b Microscopicimage showing a ciliated epithelial liningIchimura et al. Surgical Case Reports  (2017) 3:1 Page 4 of 4

Enlarged mediastinal air cyst in a patient with bronchial diverticula localized in the left main bronchus: a case report with surgical and bronchoscopic findings

Enlarged mediastinal air cyst in a patient with bronchial diverticula localized in the left main bronchus: a case report with surgical and bronchoscopic findings

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