Because of the presence of a moderate-size pneumothorax in this patient, a tube thoracostomy was performed and a 16-Fr chest tube was placed in the left pleural cavity that was connected to water seal chest tube drainage system. This resulted in complete lung expansion and resolution of the pneumothorax. For the treatment of the herniated lung, it was decided to manage patient conservatively with analgesia and thoracic strapping. Chest tube was removed within the next few days after cessation of the air leak in the tube drainage system. Repeat CT scan of the chest after removal of the chest tube showed almost complete regression of the herniated lung tissue back into thoracic cavity. His impressive subcutaneous emphysema also improved significantly during the treatment course. Patient was discharged home after 7 days of hospitalization with an advice to quit smoking and lose weight.
Herniation of the lung is defined as a protrusion of the lung tissue beyond the normal boundaries of the thoracic cavity.1 It is a rare event and fewer than 300 cases of all types of lung herniation have been reported in the literature so far.2 The first reported case of lung herniation was reported by Roland in 1499. Morel-Lavalle3 later in 1845 classified lung hernias based on their location (cervical, thoracic, or diaphragmatic) and underlying cause (congenital or acquired). Acquired hernias were further classified into pathologic (due to underlying disease 18%), spontaneous (30%), and traumatic (52%). Another unusual form of lung herniation not included in this classification is “mediastinal lung herniation,” which is defined as protrusion of the lung tissue from one side of thoracic cavity to the opposite side, usually behind or above the heart. This condition is associated with some congenital cardiopulmonary anomalies like pulmonary sequestration and scimitar syndrome but rarely it can also be seen as a consequence of the hyperinflation of the contralateral lung to the opposite side of the chest cavity after resectional lung surgeries in patients with bullous emphysema, lung volume reduction surgeries in severe emphysema patients, or after pneumonectomy.4,5 Traumatic acquired forms of lung herniation related to motor vehicle accidents, seat belt injury, traumatic rib fractures, postthoracic surgery, and cardiopulmonary resuscitation are the most common forms of lung hernias. Postthoracostomy lung hernias are classified under acquired traumatic forms and can be seen in lung transplant patients as protrusion of the lung tissue through the incision mark especially when there is implantation of a large donor lung in a thoracic cage that is too small resulting in a donor recipient lung size mismatch. On occasion, this can also be iatrogenic when delayed chest closure approach is used after lung transplant surgery to help in better accommodation of the transplanted lungs in the thoracic cavity and also to decrease the incidence of intraoperative and postoperative pulmonary and myocardial edema.6,7
Spontaneous lung herniation is very unusual and it most frequently occurs in men with obesity and history of smoking. The underlying mechanisms of acquired spontaneous lung hernia involve acute increase in intrathoracic pressure as occurs in vigorous coughing or sneezing or heavy weight lifting. A common anatomic site of predilection in the anterior thoracic wall is the area between the eighth and ninth ribs where the external intercostal muscle is lacking and in the posterior thoracic wall the area from costal angle to the vertebrae is more prone for this complication because of the absence of internal intercostal muscle. Underlying conditions like COPD, chronic steroid use, tuberculosis, collagen vascular diseases, and malignancy may predispose to the development of this condition.8,9
Most of the spontaneous lung hernias are asymptomatic and are usually detected incidentally on chest imaging. Symptomatic patients usually present with a bulging swelling through the chest wall that increases in size with inspiration and decreases in size with expiration. The classic history includes acute chest pain after vigorous coughing or sneezing. Important clues to the diagnosis on physical examination include exacerbation of hernia on valsalva, coughing, or straining.8 Chest radiograph is usually the first thoracic imaging modality used for diagnosis after suspicious physical examination. Positive clues in the chest radiograph findings include demonstration of lung markings beyond the bony thorax also known as “lung beyond rib sign” or hernia may be seen as a focal lucent area called “lucent lung sign.”10 However, it is important to remember that chest radiographs may be completely normal in many patients despite the presence of underlying hernia.
CT scan is usually diagnostic; moreover it also gives a detailed anatomic location of the defect that can be used in surgical treatment planning. Herniated lung is usually seen as a bulge outside the thoracic cavity on an axial CT scan (Fig. 2A).10 The best way to demonstrate the bulge is probably the multiplanar reconstruction of the CT images in coronal view (Fig. 2B). Additional advantage of the CT scan is in its ability to aide in delineating associated underlying thoracic injuries such as rib fractures, vascular injuries, and pneumothorax.
Management of spontaneous lung herniation is still controversial and it depends on various factors like patient’s symptoms, underlying diseases, overall health status, and size of the chest wall defect and viability of the herniated lung tissue. Asymptomatic patients are best managed by conservative nonsurgical measures such as medications for cough suppression, compressive pads, and corsets.11 Surgery is indicated in symptomatic patients with severe pain, recurrent infections caused by strangulated lung tissue, hemoptysis, or with deteriorating respiratory status. Some asymptomatic patients may opt for surgical treatment due to cosmetic reasons. For small chest wall defects, pericostal fixation of the adjacent ribs may be sufficient but for larger defects reconstructive procedures using allografts like muscles or fascia lata or synthetic materials such as marlex mesh or polytetrafluoroethylene patch are preferred.9
In summary, our case highlights the important clinical and imaging findings seen in spontaneous thoracic lung herniation that is a rare and unusually encountered clinical entity. Some of the take home points from this case report include:
1. The diagnosis of spontaneous lung herniation should be considered in patients who present with acute chest pain and shortness of breath after vigorous coughing, sneezing, or any other strenuous activity.
2. Important physical examination clue include the presence of reducible mass in the affected chest wall that increases in size with inspiration and decreases with expiration.
3. Chest radiograph should be the first radiologic examination of choice but it can be normal in many patients. CT scan is the diagnostic test of choice.
4. Asymptomatic cases can be managed conservatively with compressive pads and corsets but symptomatic patients usually require surgical repair.
1. Tack D, Wattiez A, Schtickzelle JC, et al..Spontaneous lung herniation after a single cough.Eur Radiol.2000;10:500–502.
2. Goverde P, Van Schil P, Brande F, et al..Chronic herniation of the lung in a patient with chronic obstructive pulmonary disease.J Thorac Cardiovasc Surg.1998;46:164–166.
3. Morel-Lavalle A.The lung hernia.Bull Soc Chir Paris.1845;1:75–195.
4. Fujisawa H, Tanaka E, Kushihashi T, et al..Mediastinal lung herniation associated with pulmonary sequestration.J Thorac Imaging.2007;22:369–373.
5. Grillo HC, Shepard JA, Mathisen DJ, et al..Postpneumonectomy syndrome: diagnosis, management, and results.Ann Thorac Surg.1992;54:638–650.
6. Krishnam MS, Suh RD, Tomasian A, et al..Postoperative complications of lung transplantation: radiologic findings along a time continuum.Radiographic.2007;27:957–974.
7. Force SD, Miller DL, Pelaez A, et al..Outcomes of delayed chest closure after bilateral lung transplantation.Ann Thorac Surg.2006;81:2020–2024.
8. Jastrow KM III, Chu D, Jaroszewski D, et al..Posterior lung herniation after a coughing spell: a case report.Cases J.2009;2:86.
9. Sulaiman A, Cottin V, De Souza Neto EP, et al..Cough-induced intercostal lung herniation requiring surgery: report of a case.Surg Today.2006;36:978–980.
10. Zia Z, Bashir O, Ramjas GE, et al..Intercostal lung hernia: radiographic and MDCT findings.Clin Radiol.2013;68:e412–e417.
11. Gómez PE, Ferreiro S, Esteban SM, et al..Spontaneous pulmonary hernia: a case report.Respir Care.2013;29. [Epub ahead of print].
Keywords:© 2014 by Lippincott Williams & Wilkins.
lung herniation; chronic obstructive pulmonary disease; pneumothorax