Incidental finding of congenital thoracic malformations in adult population.

Objective: Evaluation of abnormal adult chest computed tomography (CT) scans.

Study Design: Retrospective series of 3 cases.

Setting: Two University-based hospitals.

Intervention: Three adult patients (age range 56 to 61) underwent chest CT scans. Two were trauma patients and one complained of chest pain with a negative cardiac workup. One CT scan revealed a lung mass that was highly suspicious for malignancy and the other two CT scans were suspicious for diaphragmatic hernia. Two patients underwent elective surgery and the third underwent emergent surgery.

Results: The CT scan of patient 1 was suspicious for malignancy; however, the pathology of the lung mass revealed only inflammation consistent with an intralobular bronchopulmonary sequestration. Patient 2 had a congenital Morgagni hernia with omentum and colon in the mediastinum, and patient 3 had a diaphragmatic defect combined with a bifid sternum and defective pericardium, fulfilling three criteria of pentalogy of Cantrell.

Conclusion: Thoracic congenital malformations may go unnoticed and unsuspected until adulthood. They should be kept in mind when reviewing unusual CT scans of the chest in adults. Their surgical management, however, is similar to their counterparts in infancy.

Key Words: congenital malformations, Morgagni hernia, pentalogy of Cantrell, diaphragmatic hernia, intralobar sequestration, chest CT

**********

Most thoracic congenital abnormalities are identified either at birth or due to complications in the early postnatal period when diseases such as malignancy are rare. However, some congenital abnormalities escape detection and remain asymptomatic, only to be found incidentally after obtaining imaging for an unrelated problem.

We report three cases in adults: one pulmonary sequestration and two diaphragmatic hernias, one of which had 3 of 5 features of the pentalogy of Cantrell. All were found incidentally, and two had radiographic features suspicious for alternate pathologies.

Case Reports

Patient 1

A 61-year-old male with history of hypertension was involved in a motor vehicle accident sustaining multiple injuries, including right-sided rib fractures. A computed tomography (CT) of the chest demonstrated a 3 X 2 cm spiculated mass in the right lower lobe which was highly suspicious for cancer (Fig. 1). CT scans of the head, abdomen and pelvis were negative for metastatic disease. He had an extensive history of tobacco abuse and dyspnea on exertion but no recurrent bronchitis or pneumonia. The patient desired to "recover" from his accident, and a repeat chest CT was obtained one month later which was unchanged. A right thoracotomy was performed. The mass was located in the basal medial segment of the right lower lobe. As the inferior pulmonary ligament was taken down, there was extensive arterial bleeding from a very friable vessel branching off directly from the abdominal aorta. A formal segmentectomy was performed. Frozen section did not reveal malignancy, and the final pathology revealed fibrosis, dilated glandular spaces and inflammation consistent with intralobar bronchopulmonary sequestration (Fig. 2). The postoperative course was unremarkable and the patient had no complaints after six months of follow-up.

Patient 2

A 60-year-old female with a history of chronic obstructive pulmonary disease, hyperlipidemia, severe tobacco abuse and gastroesophageal reflux disease (GERD) presented to the hospital with a primary complaint of severe chest pain. During her otherwise negative cardiac workup, a chest x-ray demonstrated a right pericardiophrenic mass (Fig. 3). Subsequent CT scanning revealed extensive herniation of fat, and a portion of colon in her right anterior chest, with compressive atelectasis of her right middle lobe (Fig. 4). Following pulmonary function testing and a stress test, the patient was deemed to be an adequate surgical candidate, and after one month of smoking cessation, she was scheduled for elective repair. The hernia was approached via an upper abdominal incision. A 10 X 20 cm defect was discovered in the characteristic location of a right Morgagni hernia. The hernia sac contained a large amount of omentum and the entire length of transverse colon. Exploration of the left and right hemidiaphragms failed to reveal additional hernias. Pathology yielded a specimen consistent with a hernia sac. The patient tolerated the procedure well, and her postoperative course was unremarkable. The patient had no complaints on follow-up, and chest x-ray remained normal.

Patient 3

A 56-year-old male trauma patient was admitted to the hospital after a high velocity car accident. On clinical examination, the patient had some epigastric tenderness and CT demonstrated a large anterior diaphragmatic hernia (Fig. 5). He underwent exploratory laparotomy for repair of the defect. Intraoperatively, the patient was found to have a large anterior diaphragmatic hernia (Fig. 6), a bifid distal sternum and xiphoid, with absence of the pericardium. In this area, there was a free connection between the peritoneal and pericardial spaces. The stomach and a portion of the colon were found within the mediastinum. A hernia sac was absent. Repair was achieved with a double layer Gore-Tex mesh (Fig. 7). The patient tolerated the procedure well, and follow-up demonstrated no recurrence of the hernia.

Discussion

Bronchopulmonary sequestration (BPS), first described by Pryce (1) in 1946, is an embryologic abnormality of lung development. It derives its arterial supply from the systemic arteries rather than from the pulmonary systems, and in addition, it may not develop normal communication with the bronchial tree. It is exceedingly rare, accounting for 0.15 to 6.4% of all congenital lung malformations. Two forms are described: intralobar sequestration (ILS), which accounts for 75% of cases, and extralobar sequestration (ELS), which accounts for 25% (2) The coexistence of both forms is extremely rare. (3) ILS is located in the lower lobes in 90% of reported cases, and typically is found in the medial or posterior basal segments. (2) The arterial supply is systemic in origin, usually arising from the aorta or a branch vessel. Venous drainage is generally via the pulmonary veins, though drainage to the systemic venous system is also known to occur. (4) This differs in the case of ELS, which frequently has a systemic venous connection.

[FIGURE 1 OMITTED]

[FIGURE 2 OMITTED]

[FIGURE 3 OMITTED]

Pulmonary sequestration is the result of an accessory lung bud that develops from the ventral primitive foregut as it migrates caudally. The sequestration retains the splanchnic blood supply, subsequently receiving systemic arterial supply instead of normal pulmonary arterial supply. The anomalous artery (or arteries in 15% of cases) arise 75% of the time from the thoracic aorta, (2) less frequently from the abdominal aorta and enter the lung via pulmonary ligament. While a systemic arterial supply is a feature of BPS, it is not pathognomonic; it is also found in congenital conditions such as arteriovenous malformation, or acquired in conditions such as chronic inflammation or infection of the lung. (5)

[FIGURE 4 OMITTED]

[FIGURE 5 OMITTED]

Presentation varies from the incidental finding of a mass in an asymptomatic patient to fever, chest pain, dyspnea, hemoptysis, recurrent bronchitis and pneumonia. In contrast to ILS, ELS is frequently asymptomatic. However, it is associated with other congenital abnormalities, including diaphragmatic hernia, cystic adenomatoid malformation, duplications of GI tract, tracheoesophageal fistula, cardiovascular defects, and renal abnormalities. (6) It is reported that 15% are asymptomatic, and 40% of patients are older than 40 years of age. (2) Our patient is the 6th oldest reported person diagnosed with ILS.

[FIGURE 6 OMITTED]

[FIGURE 7 OMITTED]

Pathologic studies have documented single or multiple cysts that contain air, mucus, or pus. The cysts are lined with respiratory epithelium and have various amounts of cartilage and bronchial glands in their walls. Because of the lack of a normal communication with the airway, the sequestration typically lacks anthracotic pigmentation; however, there may be collateral ventilation that may be present congenitally, or as the result of a pathologic connection due to inflammation and infection. (2) In addition to cysts, connective tissue, inflammatory cells and alveoli may also be present. (2.5) Differential diagnosis includes pneumonia, lung abscess, bronchiectasis, empyema, bronchogenic cysts and neoplasm.

Angiography is the most useful method to establish the exact diagnosis, but a noninvasive approach like CT, MRI, or MRA may be helpful. CT demonstrates the anomalous systemic artery in 80% of cases, (8) which may prevent excessive blood loss from accidental division of the systemic artery. Venous drainage may not be clearly demonstrated on CT. An enlarged azygos system (azygos and hemiazygos diameters together equal greater than 10 mm) (2) associated with a posterobasal chest lesion may suggest the diagnosis. Characteristic CT findings are either a cystic or complex lung lesion associated with emphysema or any basal lesion supplied by a systemic artery. CT findings are the same among children and older adults. (8) MRI is better at demonstrating the systemic arterial supply to a sequestration. The limitation of MRI is that small vessel disease is not detected and cannot delineate focal thin-walled cysts as well as CT. Three dimensional contrast-enhanced MRA allows demonstration of arteries and veins separately and does not require proper orientation of the plane of acquisition. The imaging is not flow-dependent, allowing improved visualization of smaller vessels. (2)

Even in asymptomatic intralobar sequestration, most authors recommend prophylactic resection, (9) as there is likelihood of infection as well as danger of hemorrhage, heart failure and malignant degeneration. Surgical options include segmentectomy, lobectomy, and ligation of the anomalous artery.

Congenital diaphragmatic hernias (CDH) are an uncommon occurrence with an incidence of 1 in 2,500 births. (10) Of these, anterior hernias through the foramen of Morgagni comprise only 1 to 5%. (10) Congenital anomalies of this type typically present in infancy or childhood with signs and symptoms of respiratory distress or recurrent pneumonia. Rarely, Morgagni hernias present with primarily gastrointestinal symptoms related to obstruction, incarceration, or strangulation.

Congenital diaphragmatic hernias are considered to be sporadic in occurrence; however, there are several reports with affected siblings, with one case of twins. (11) The anomaly is thought to arise from a defect in the fusion of the diaphragm to the sternum and costal cartilage. (12) It is also thought to be possible for these hernias to arise during adult life, in association with factors such as connective tissue disease, chronic constipation, obesity, and a history of trauma. Most Morgagni-type hernias are right sided (90%) with a hernia sac (95%). (13) The most common contents are the omentum and transverse colon; the stomach, liver and small intestine are herniated less frequently. (14)

In adults, this type of hernia is often asymptomatic; most are diagnosed incidentally on a chest x-ray, or some other imaging modality, as was the case with our patient. (15) Traditionally, this type of hernia has been considered longstanding and clinically insignificant. However, they can become symptomatic. Patient complaints attributable to this type of hernia include chest pain or retrosternal pressure, abdominal pain and other gastrointestinal complaints, as well as symptoms related to the respiratory and cardiovascular systems. Morgagni hernias may also present as bowel obstruction, (15) a thoracic lipomatous tumor, (12) pleural effusion, (16) or acute respiratory distress.

Diagnosis is often suspected based on the incidental findings of a right-sided, rounded, cardiophrenic mass. (14) Depending upon the contents, the hernia may simulate a lipoma or effusion, and a hollow abdominal viscus may or may not be present. A variety of confirmatory tests are available, including upper GI series, barium enema, CT scan, MRI, and selective mesenteric angiography.

Management of the anterior diaphragmatic hernia varies according to the age and presentation of the patient. In neonates who often present with acute decompensation and respiratory distress, repair is recommended after respiratory stabilization. For children with a delayed or nonacute presentation, the timing of correction remains controversial. A similar quandary exists among the adult population. Historically, Morgagni hernias in adults have been considered clinically insignificant; however, surgical repair is either recommend universally or selectively, citing the risk of incarceration or strangulation. (13,4) This, however, remains a controversial topic.

The pentalogy of Cantrell is a rare syndrome with a prevalence of 5.5 per one million in one series. (17) It is frequently fatal due to the severe nature and extent of the presenting abnormalities. It involves defects in the diaphragm, abdominal wall, chest wall, pericardium, and cardiac muscle.

Since the original description in 1953 by Cantrell, Haller, and Ravitch, subsequent studies have suggested that it may represent a subset of disorders linked to the X chromosome resulting from a single gene mutation that disrupts embryonic development in the ventral midline. It also produces cleft lip, both with and without cleft palate. (18) A family has been reported which demonstrated three brothers with extensive diaphragmatic defects, two with the complete pentalogy and one with an ectopia cordis. (19)

Treatment of patients with this wide variety of defects requires surgical correction, the timing of which is still controversial. The correction of cardiac anomalies in patients with low cardiac function should precede the repair of the abdominal wall and diaphragmatic defects. It is agreed that surgery should be done in infancy owing to a technically easier procedure and decreased risk of pulmonary hypoplasia and external cardiac compression. (18)

Conclusion

Thoracic congenital malformations are a relatively rare entity among the general population. They are uncommon in the adult population due to detection and correction in childhood. Furthermore, in the adult population, there are a large number of pathologies such as carcinoma, coronary artery disease, gastroesophageal reflux disease, pneumonia, and acute and chronic bronchitis which are much more common. However, these malformations should be kept in mind when reviewing unusual CT scans of the chest in asymptomatic adults. Surgical management, when indicated, is similar in children and adults.

References

1. Pryce DM. Lower accessory pulmonary artery with intralobar sequestration of lung: a report of seven cases. J Pathol 1946;58:457-467.

2. Petersen G, Martin U, Singhal A, et al. Pulmonary sequestration in the middle-aged and elderly adult: recognition and radiographic evaluation. J Thorac Cardiovasc Surg 2003;126:2086-2090.

3. Shibli M, Connery C, Shapiro JM. Intralobar and extralobar bronchopulmonary sequestration complicated by Nocardia asteroides infection. South Med J 2003;96:78-80.

4. Albanese CT. Pediatric surgery. In: Norton JA, Bollinger RR, et al, eds. Surgery: Basic Science and Clinical Evidence. 1st ed. New York, Springer, 2001, pp 2069-2819.

5. Kirks DR, Kane PE, Free EA, et al. Systemic arterial supply to normal basilar segments of the left lower lobe. AJR Am J Roentgenol 1976;126: 817-821.

6. Savic B, Birtel FJ, Tholen W, et al. Lung sequestration: report of seven cases and review of 540 published cases. Thorax 1979;34:96-101.

7. Iwai K, Shindo G, Hajikano H, et al. Intralobar pulmonary sequestration, with special reference to developmental pathology. Am Rev Respir Dis 1973;107:911-920.

8. Ikezoe J, Murayama S, Godwin JD, et al. Bronchopulmonary sequestration: CT assessment. Radiology 1990;176:375-379.

9. O'Mara CS, Baker RR, Jeyasingham K. Pulmonary sequestration. Surg Gynecol Obstet 1978;147:609-616.

10. Singh S, Bhende MS, Kinnane JM. Delayed presentations of congenital diaphragmatic hernia. Pediatr Emerg Care 2001;17:269-271.

11. Tazuke Y, Kawahara H, Soh H, et al. Congenital diaphragmatic hernia in identical twins. Pediatr Surg Int 2000;16:512-514.

12. Gerard PS, Wilck E, Senderoff E, et al. Morgagni hernia mimicking a lipomatous tumor. N Y State J Med 1993;93:58-59.

13. Harris GJ, Soper RT, Kimura KK. Foramen of Morgagni hernia in identical twins: is this an inheritable defect? J Pediatr Surg 1993;28:177-178.

14. LaRosa DV Jr, Esham RH, Morgan SL, et al. Diaphragmatic hernia of Morgagni. South Med J 1999;92:409-411.

15. Wong NA, Dayan CM, Virjee J, et al. Acute respiratory distress secondary to Morgagni diaphragmatic herniation in an adult. Postrad Med J 1995;71:39-41.

16. Sekiguchi Y, Shimura S, Takishima T,. Intrapleural omentum simulating pleural effusion. Chest 1994;106:285-287.

17. Carmi R, Boughman JA. Pentalogy of Cantrell and associated midline anomalies: a possible ventral midline developmental field. Am J Med Genet 1992;42:90-95.

18. Online Mendelian Inheritance in Man, OMIM (TM). Johns Hopkins University, Baltimore, MD. MIM Number: {313850}: {12/10/2002}. Available at: http://www.ncbi.nlm.nih.gov/omim/

19. Martin RA, Cunniff C, Erickson L, et al. Pentalogy of Cantrell and ectopia cordis, a familial developmental field complex. Am J Med Genet 1992;42:839-841.

Mehdi Akhavan-Heidari, MD, Devin Edwards, MD, Jessica Besenhaver, MS, and Rebecca Wolfer, MD

From the Department of Surgery, Marshall University, Huntington, WV.

Reprint requests to Mehdi Akhavan-Heidari, MD, Department of Surgery, Marshall University School of Medicine, 1600 Medical Center Drive, Huntington, WV 25701. Email: [e-mail]

Accepted January 30, 2006.

RELATED ARTICLE: Key Points

* Congenital abnormalities are uncommon in the adult population due to detection and correction in childhood.

* Missed congential defects can be found incidentally in adulthood with imaging for an unrelated problem.

* Missed congenital abnormalities should be kept in mind when reviewing unusual CT scans of the chest in asymptomatic adults.

* Surgical management of congenital abnormalities is similar in adults and in children.