Ann Thorac Surg 2008;86:1693-1695. doi:10.1016/j.athoracsur.2008.04.004
© 2008 The Society of Thoracic Surgeons
Case Reports
Transthoracic Repair of an Unsuspected Left Foramen of Morgagni Hernia
Barbara L. Robinson, MDa,b,c,*,
David M. Shahian, MDa,b
a Department of Cardiac Surgery, Children's Hospital Boston, Harvard Medical School, Boston, Massachusetts
b Lahey Clinic, Burlington, Massachusetts
c Tufts University School of Medicine, Boston, Massachusetts
Accepted for publication April 1, 2008.
* Address correspondence to Dr Robinson, Bader 279, Department of Cardiac Surgery, Children's Hospital Boston, 300 Longwood Ave, Boston, MA 02115 (Email: anistasia36{at}yahoo.com).
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Abstract
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Left-sided foramen of Morgagni herniae are rare and may present both diagnostic and therapeutic challenges. This case report describes chronically herniated greater omentum mimicking an enlarging fatty tumor requiring transthoracic repair.
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Introduction
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Foramen of Morgagni hernias are rare and typically present in the right hemithorax. We describe an unusual left-sided presentation in which herniated omentum occupied most of the hemithorax, mimicking a fatty tumor such as lipoma or liposarcoma. Transthoracic repair was achieved, which may be preferable to the abdominal approach if the hernia is chronic (and thus more likely to have dense adhesions) or if the diagnosis is uncertain. If the defect can not be primarily repaired without tension, patch repair with Gore-Tex (W. L. Gore & Assoc, Flagstaff, AZ) is preferred.
A 51-year-old ex-diver and carpenter, with no history of trauma, presented with an enlarging but completely asymptomatic mass in the left hemithorax. This mass was originally identified several years previously at another institution and diagnosed as an intrathoracic lipoma. Observation was recommended because of the presumed benign nature of the lesion. Because recent chest roentgenograms revealed enlargement of the mass, he sought a second opinion.
On physical examination, the patient had a regular pulse of 112, blood pressure of 132/96, room air oxygen saturations of 98%, and decreased left-sided breath sounds.
Serial chest roentgenograms revealed an enlarging soft-tissue density filling the lower half of the left chest (Fig 1). Computed tomography demonstrated a fat density mass in the left hemithorax that was contiguous with the left anterior chest wall, sternum, diaphragm, pericardium, and great vessels, resulting in displacement of the left lung superiorly and posteriorly (Fig 2). The craniocaudad dimension was 25 cm, spanning from just above the aortic knob to the level of the diaphragm. Laterally, the lesion measured 20 cm from the pericardium to the left lateral chest wall. At the level of the left-sided pulmonary veins there was some cardiac displacement to the right of the midline, and on retrospective review, a small portion of the transverse colon was noted to lie immediately behind the lowermost aspect of the sternum (Fig 3).
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Fig 1. Preoperative anterior-posterior chest roentgenogram shows a soft-tissue mass in the left hemithorax.
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Fig 2. Preoperative chest computerized tomographic scan shows a fatty homogeneous, retrosternal left chest mass extending superiorly to level of aortic arch.
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Fig 3. Preoperative chest computerized tomographic scan demonstrating mid-transverse colon located in the lowermost retrosternal location.
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Because of the demonstrated enlargement of the lesion and the potential for malignancy, exploration was recommended. The primary differential diagnoses included an intrathoracic lipoma or liposarcoma. Given the location in the left chest, a Morgagni hernia was believed to be unlikely, as they are predominantly right-sided. At exploration through a left sixth intercostal space thoracotomy, a large fatty lesion was encountered that was densely adherent to the pericardium, lung, diaphragm, and chest wall. As these adhesions were lysed, it became apparent that this was a large hernia sac emerging from a foramen of Morgagni. The sac was entered, revealing herniation of the entire greater omentum. Anteriorly there was minimal muscular rim, and the strongest available tissue was periosteum. Laterally and posteriorly there was a 1-cm rim of diaphragmatic muscle. The phrenic nerve was not visualized due to dense adipose tissue. Neither the omentum nor the sac could be reduced back into the abdomen, necessitating resection of both. The Morgagni hernia defect was then repaired with a 4 x 6 cm Gore-Tex patch (W. L. Gore & Assoc) using interrupted zero Ethibond (Ethicon Inc, Somerville, NJ) sutures (Fig 4) with pledgets, three quarters of the circumference medially, posteriorly, and laterally, directly into diaphragmatic muscle and anteriorly, directly into the periosteum, which had excellent tensile strength. The patient did well postoperatively and has returned to work. Late follow-up chest roentgenograms reveal elevation of the left hemidiaphragm, suggesting phrenic nerve paresis. The patient has no clinical sequelae and continues to work as a transcontinental truck driver.
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Fig 4. A 5-cm Gore-Tex patch (W. L. Gore & Assoc, Flagstaff, AZ) repair of left-sided anterior foramen of Morgagni defect after the greater omentum was excised.
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Comment
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Foramen of Morgagni hernia was first described by Giovanni Morgagni in 1769 [1]. It is the least common congenital diaphragmatic hernia (2% to 5%) with an overall prevalence of 1 per 1 million births. It may occur as congenital [2], acquired, or in mixed forms [3]. Although they may be found in the pediatric population, they are more typically present in mid-life. Because of the blocking effect of the pericardium on the left, these herniae are located on the right side in more than 90% of patients [4, 5]. Anatomically, Morgagni hernias result from an anterior retrosternal defect at the sternocostal trigone, also referred to as the space of Larrey, through which the internal mammary artery passes to become the superior epigastric artery. This defect is due to anomalous insertions of diaphragmatic muscle bundles and lack of fusion of the anterior part of the pleuroperitoneal membrane.
Most patients with Morgagni herniae have a well-formed hernia sac, typically containing omentum or colon, or both, but occasionally the stomach, liver, falciform ligament, gallbladder, spleen, kidney, adrenal gland, or pancreas. Rarely are there are no contents at all [5–7]. Despite herniated viscera, many patients are asymptomatic and their hernias are discovered incidentally. When present, symptoms in the adult may result from visceral herniation with subsequent strangulation, obstruction, or compressive respiratory or gastrointestinal tract symptoms. Physical signs may include diminished breath sounds, the presence of bowel sounds in the chest, or hyperresonance. Obesity, as present in our patient, may have resulted in increased intra-abdominal pressure, promoting omental and visceral herniation into the chest.
Computerized tomographic scanning revealed the characteristic anterior location with soft tissue above and below the diaphragm [5–7]. If the hernia sac contains primarily omentum, fat density will be seen within the intrathoracic mass, and omental blood vessels may be visible, which were not evident in our patient's computed tomographic scan. An abnormally high location of the transverse colon may be observed if it is tethered to the herniated greater omentum [5]. In retrospect, this radiographic finding was present in our patient (Fig 3). Other diagnostic modalities may include magnetic resonance imaging, barium studies of the gastrointestinal tract, thoracoscopy, and laparoscopy.
Elective surgical treatment of foramen of Morgagni is indicated once the diagnosis is made, regardless of age, to prevent potentially emergent complications, such as incarceration and strangulation. Both transabdominal and transthoracic approaches, either open or endoscopic, have been used [5, 8]. We opted for thoracotomy because of the patient's morbidly obese abdomen, the large and indeterminate nature of the thoracic mass, the possibility of malignancy, and the high likelihood of thoracic adhesions secondary to chronicity of this lesion. The operative findings demonstrated that the omentum could not be reduced and required resection within the chest. To achieve a secure and tension-free closure of the defect, a prosthetic patch was used.
This case demonstrates the rare occurrence of a left-sided, chronic foramen of Morgagni hernia with herniated omentum. Although transabdominal repair is usually preferred for the repair of Morgagni hernias, this case illustrates several factors favoring a transthoracic approach.
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References
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- Morgagni GB. De sedibus et causis morborum. Lib III. Venezia, 1761. The seats and causes of diseases investigated by anatomy. (Translated by B. Alexander), Vol. 3. lir 54. London, United Kingdom: A Millar, T Cadell; 1769. pp. 205-207.
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Abstract
Introduction
