Lung Herniation

56M with new chest mass after recent cardiac surgery • Xray of the Week

56 yo M with complaints of new chest mass, cough and chest pain. Patient recently had a minimally invasive secundum ASD and PFO closure. Patient noticed a mass bulging on his right side at the surgical site when coughing. What is the diagnosis?

Figure 1. Patient with history of recent cardiac surgery presents with palpable right chest mass. What is the diagnosis?

Figure 2. CT chest with contrast axial image shows a portion of the anterior basal segment right lower lobe herniating between two anterior ribs. Also noted is a large right hemothorax.

Figure 3. CT chest oblique coronal image (A) with a volume rendered oblique coronal reconstruction image (B) again shows a portion of the anterior basal segment right lower lobe herniating between two anterior ribs.

Figure 4. CT chest without contrast axial image after thoracotomy, lung herniation repair with pneumolysis of the anterior basal segment of the right lower lobe and drainage of a previous hemothorax with a chest tube (orange arrow).

Discussion:

Lung herniation occurs uncommonly, with 20% due to a congenital anomaly, and the remaining 80% acquired. Causes of acquired lung herniation include infection, neoplasm, trauma, and (as seen in this case) from recent or remote thoracic surgery [1]. Lung herniation most commonly occurs in the anterior region especially in the lower intercostal spaces due to less muscular support (Figs. 1-3) [1,2]. Postoperative lung herniations are more common during less extensive surgical procedures and minimally invasive surgeries compared to more extensive procedures that involve a thoracotomy due to technique in closure [1]. Congenital hernias result from a defect in the endothoracic fascia with absence of intercostal musculature or due to costal malformations [2]. Pathological causes of lung herniation usually include infections or neoplasms such as breast cancer or metastasis of the chest wall that erode and weaken the intercostal musculature [2]. History usually reveals a palpable mass and chest wall pain that worsen after coughing, sneezing or actions that increase intrathoracic pressure [3]. History and physical exam including examination of the chest wall with Valsalva maneuver are best at first diagnosing lung herniation as an initial chest radiograph may not reveal the diagnosis [3, 4].

Ultrasound can be used to easily differentiate herniated lung tissue that is filled with air compared to soft tissue, fat or fluid lesions such as a lipoma or hematoma [4]. Expiratory CT scans can exaggerate the lung herniation to improve diagnosis sensitivity and can provide additional information such as the possibility of lung strangulation to deduce viability of lung tissue before surgery [4].

Emergent indications for surgery include signs or increased risk of lung incarceration and strangulation [3]. This may include a non-reducible bulge on physical exam or narrowing of the pulmonary vasculature, small airways and neck of the hernia on imaging [3]. There is currently no consensus on management of nonemergent lung herniation. Conservative management such as compression is mostly reserved for high comorbid conditions, but long term complications may lead to reduced pulmonary compliance, atelectasis or infection [3,5]. Surgical management such as resection of incarcerated lung, pneumolysis (Fig. 4), pericostal fixation, reduction with mesh, or muscle flaps can be done with good long term outcomes [6, 7].

References:

1. Scelfo C, Longo C, Aiello M, Bertorelli G, Crisafulli E, Chetta A. Pulmonary hernia: Case report and review of the literature. Respirol Case Rep. 2018;6(8):e00354. Published 2018 Oct 2. doi:10.1002/rcr2.354 2. Moncada R, Vade A, Gimenez C, et al. Congenital and acquired lung hernias. J Thorac Imaging. 1996;11(1):75-82. doi:10.1097/00005382-199601110-00008 3. Chaturvedi A, Rajiah P, Croake A, Saboo S, Chaturvedi A. Imaging of thoracic hernias: types and complications. Insights Imaging. 2018;9(6):989-1005. doi:10.1007/s13244-018-0670-x 4. Detorakis EE, Androulidakis E. Intercostal lung herniation--the role of imaging. J Radiol Case Rep. 2014;8(4):16-24. Published 2014 Apr 1. doi:10.3941/jrcr.v8i4.1606 5. Mirza A, Gogna R, Kumaran M, Malik M, Martin-Ucar A. The surgical management of intercostal lung herniation using bioprosthesis. J Surg Case Rep. 2011;2011(2):6. Published 2011 Feb 1. doi:10.1093/jscr/2011.2.6 6. Chiang TY, Yin MF, Yang SM, Chen KC. Thoracoscopic management of incarcerated lung herniation after blunt chest trauma: a case report and literature review. J Thorac Dis. 2017;9(3):E253-E257. doi:10.21037/jtd.2017.03.41 7. Chu MW, Losenno KL, Fox SA, et al. Clinical outcomes of minimally invasive endoscopic and conventional sternotomy approaches for atrial septal defect repair. Can J Surg. 2014;57(3):E75-E81. doi:10.1503/cjs.012813

Steven M. Lee, MD is a diagnostic radiology resident at the John P. and Kathrine G. McGovern Medical School at UTHealth in Houston, Texas. The McGovern Radiology Residency program has a Trauma Level 1 Emergency Department at MHH-TMC, and a top cancer center at MDACC. The location in the Texas Medical Center, the largest in the world, provides a unique training experience with access to numerous faculty, resources, and research opportunities. Dr. Lee graduated from the University of Texas at Austin as a Psychology major and earned his medical degree from McGovern Medical School.

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Cihan Duran, MD is an Associate Professor of Radiology at The University of Texas McGovern Medical School in Houston. She received her medical degree from Hacettepe University in Turkey. After completing her residency at Istanbul University, she worked in Group Florence Nightingale/ Istanbul Bilim University as a body and cardiothoracic imaging faculty. After she came to the United States, she worked as a research fellow in Advanced Cardiovascular Imaging Laboratory at Harvard University. She completed her fellowship in Cardiovascular MRI at Baylor College of Medicine St. Luke’s Episcopal Hospital and Thoracic Radiology, Musculoskeletal Radiology, and Body Imaging fellowships in MD Anderson Cancer Center. Dr. Duran authored and co-authored over 65 peer-reviewed articles; multiple book chapters and over 100 abstracts and scientific and educational exhibits at National and International conferences on the topics of cardiothoracic and body imaging. She serves as a journal reviewer for several scientific journals.