Don't Put Your Brain on Hiatus: Abnormalities at the Gastroesophageal Junction on Chest RadiographyO’Connor SD, Meyer CA, Kanne JP, Yandow DP

The gastroesophageal junction is the “no man’s land” of the lower mediastinum, straddling the turf of thoracic and abdominal imagers. Abnormalities on a chest radiograph are often assumed to represent the most commonly occurring abnormality in this region, the sliding hiatal hernia.

Processes involving the esophagus, stomach, liver, pancreas, aorta, lung, nerves, and lymph nodes are included in the differential diagnosis of abnormalities at the level of the gastroesophageal (GE) junction.

Introduction

Knowledge of the spectrum of pathology occurring at the gastroesophageal junction assists the alert radiologist to develop a more accurate differential diagnosis in this often overlooked region.

Conclusion

The pedestrian hiatal hernia (Figures 1 and 2) is the most likely etiology of a mass at the gastroesophageal junction. Most consist of gastric fundus and present as rounded masses with air-fluid levels, usually to the left of midline on the PA chest radiograph (1). If the esophageal hiatus is patulous, the entire stomach may rotate on its long axis (organoaxial volvulus) and pass through the hiatus (2) or other intrabdominal organs may traverse the hiatus.

Enteric System

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it? How do we recognize it? How do we manage it? J Vasc Surg. 1998;27:1006-15; discussion 1015-6. 12. Feuerlein S, Kreuzer G, Schmidt SA, et al. The cisterna chyli: prevalence, characteristics and predisposing factors. Eur

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References

MiscellaneousVascular System, continuedA bronchogenic carcinoma (Figure 17) in the azygo-esophageal recess may simulate a gastroesophageal junction lesion on chest radiography. The lack of air within the abnormality should prompt further investigation.

Lymphatic system

Figure 17: Small cell carcinoma in a 55-year-old heavy smoker

a, b) PA and lateral radiographs with mass dextrolateral to the gastroesophageal junction.

c) Unenhanced CT confirms a mass in the crista pulmonis of the right lower lobe abutting the esophagus.

a b

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Figure 1: Hiatal hernia in a 62-year-old woman

a, b) PA and lateral radiographs with a large air-containing midline mass

c-e) Contrast-enhanced CT demonstrating large hiatal hernia.

Figure 2: Hiatal hernia in a 39-year-old man

a, b) PA and lateral radiographs with large solid midline mass

c) Contrast-enhanced CT demonstrating large hiatal hernia containing stomach and left hepatic lobe.

Esophageal varices (Figure 13), visible on chest radiography in 5-8% of patients, are seen as a middle or posterior mediastinal mass (2, 8). Radiographic findings of a small liver with colonic interposition, splenomegaly, or ascites may be clues to the correct diagnosis (9).

Enteric System, continued

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Esophageal duplication cysts (Figure 6) are most commonly found near the distal esophagus of asymptomatic patients. They are thin-walled, fluid-filled structures, usually adjacent to the esophagus and may contain air if they communicate with the lumen (3). If they contain ectopic gastric mucosa, patients can present with pain, hematemesis from erosion into the esophagus, or hemoptysis from erosion into the lung. 99mTc pertechnetate can help confirm the ectopic gastric tissue.

Enteric System, continued

Figure 6. Duplication cyst in a 30-year-old asymptomatic woman.

a, b) Radiographs with a mediastinal mass to the left of midline.

c) Contrast-enhanced CT with a simple fluid collection with nonenhancing rim.

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c

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Pancreatic pseudocysts (Figure 7) are thin-walled, fluid-filled structures that can develop quickly in patients with pancreatitis (4). Unless complicated by infection or hemorrhage, pseudocyst fluid is low to iso-attenuating. An abdominal pseudocyst is often, but not invariably, present.

Figure 7. Pancreatic pseudocyst in a male with chronic pancreatitis.

a) Radiograph with a mediastinal mass.

b) Sequential images from a contrast-enhanced CT with a rim-enhancing cystic mass extending from an atrophic, calcified pancreas superiorly into the mediastinum (arrows).a

Esophageal carcinoma (Figure 4) and lymphoma (Figure 5) may present as a solid midline mass or obstructed esophagus with an air-fluid level. Esophageal tumors may thicken the tracheoesophageal stripe or displace the azygoesophageal recess(2).

Figure 5. Esophageal lymphoma in a 60-year-old man with dysphagia

a) Radiograph with a convex density posterior to the right heart border without obscuring the cardiophrenic angle.

b, c) Contrast-enhanced CT with an eccentric mass of the distal esophagus without esophageal obstruction and an accompanying splenic mass.c

Figure 13: Esophageal varicesin a 40-year-old woman with portal vein thrombosis.

a, b) PA and lateral radiographs with a retrocardiac mass.

c) Contrast-enhanced CT with massive esophageal varices.

d, e) Post-contrast T1-weighted and T2-weighted MRI with massive varices.

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Figure 4. Esophageal carcinoma in a 74-year-old man with dysphagia

a, b) Radiograph with a retrocardiac mass displacing the azygoesophageal recess on the frontal view (arrow) and widening the tracheo-esophageal stripe on the lateral view (arrow).

c-e) Contrast-enhanced CT with an irregular mass filling the esophageal lumen.

Figure 8. Esophageal rupture in a 51-year-old man with chest pain.

a) Radiograph with an obscured gastroesophageal junction.

b, c) Contrast-enhanced CT with an abnormal esophageal contour and air and fluid in the mediastinum.

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c

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Figure 3. Achalasia

a, b) Radiographs with a solid retrocardiac mass and an air-fluid level (arrow).

c) Single contrast upper GI exam with severe narrowing (beaking) of the distal esophagus with proximal dilatation. This did not relax during the real-time exam.

d, e) Contrast-enhanced CT from a second patient with a fluid filled mediastinal mass that tapers inferiorly.

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Enteric System, continued

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Esophageal rupture (Figure 8) and other esophageal emergencies present with mediastinal air and/or fluid at the level of the gastroesophageal junction (5).

Gastric tumors (Figure 9) may be visible on radiography when seen through the gastric air (2, 6).

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c

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Figure 9. Gastric leiomyoma in a 29-year-old woman with epigastric pain.

a) Radiograph with abnormal gastric air.

b, c) Contrast-enhanced CT with a soft tissue mass in the gastric cardia.

10% of adult mediastinal masses arise from the vascular system, usually the descending aorta (7). A tortuous aorta(Figure 10) may mimic achalasia or other mediastinal pathology. Thoracic aortic aneurysms (Figure 11) are usually fusiform and retrocardiac. Changes and complications from aortic surgery (Figure 12) also alter the aortic contour. Aortic wall calcifications and anterior and/or left lateral vertebral body scalloping erosions may suggest the etiology.

Vascular System

Figure 14: Ruptured penetrating ulcer of the descending thoracic aorta

a) Radiograph demonstrating a retrocardiac mass.

b, c) Contrast-enhanced CT with aortic dissection with hematoma and active extravasation (arrow) of contrast from rupture.

Figure 15: Dilated cisterna chyli in a 75-year-old man with rheumatoid arthritis.

a, b) Contrast enhanced CT with a soft tissue mass adjacent to the aorta. Multiple tiny lymphatic channels feed into the inferior aspect of the mass (arrows).

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The cisterna chyli (Figure 15) is a focal dilatation of the thoracic duct at the confluence of the intestinal duct with the right and left lumbar trunks (12). It may be misinterpreted as a retrocrural lymph node or mass. Studies employing varying autopsy and imaging criteria have found a 2-83% incidence of cisterna chyli in the general population.

Corresponding Author: Stacy O’Connor, MD

soconnor@uwhealth.org

Achalasia (Figure 3) is a disturbance of esophageal smooth muscle motility, preventing lower esophageal sphincter relaxation with progressive dilation of the esophagus (1,2). While early achalasia is usually occult on chest radiography, the azygoesophageal recess bows further and further to the right as the disease progresses. Air and retained fluid/food debris create a retrocardiac mass with an air-fluid level.

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A penetrating ulcer of the descending thoracic aorta may rupture (Figure 14) with resultant mediastinal hematoma simulating an inferior mediastinal mass on radiography (10). Penetrating ulcers occur most commonly in the descending thoracic aorta and have a higher risk of rupture (40%) than aortic dissection or intramural hematoma (11).

Figure 10: Tortuous aorta in a 40-year-old man.

a) PA and lateral radiographs with a mediastinal mass.

b, c) Contrast-enhanced CT demonstrates the tortuous descending thoracic aorta crossing to the right of midline at the gastroesophageal junction.

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b c

Figure 12: Adult male who underwent coarctation repair in childhood. a, b) PA and lateral radiographs with a large retrocardiac double density obscuring the clear space on the lateral view. c, d) Contrast-enhanced CT demonstrates the distal aortic lumen and the large communication with the distal pseudoaneurysm.

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A thoracic duct cyst (Figure 16) is a smooth, oval to round cystic mass with homogeneous attenuation and without internal enhancement (13,14). These cysts may be found above or below the diaphragm; most supradiaphragmatic thoracic duct cysts are in the neck.

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Figure 16: Large thoracic duct cyst in an asymptomatic 68-year-old woman.

a, b) T2-weighted MRI images demonstrating a large thoracic duct cyst with high T2 signal and thin internal septations.

Ascites (Figure 18) can extend into the mediastinum, mimicking a cystic mediastinal mass on radiography or CT (15).

Figure 18: Ascites in an 80-year-old man with pancreatic cancer

a, b) Frontal radiograph with a mediastinal mass.

c) Contrast-enhanced CT with ascites tracking superiorly into the mediastinum and bilateral pleural effusions.

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Figure 11: Aortic aneurysm in a 75-year-old woman with back pain

a) Radiograph with midline mass

b) Unenhanced CT reveals a large, fusiform thoracic aortic aneurysm.

a b

Vascular System, continued

A plethora of other pathologies may project over the gastro-esophageal junction on chest radiography. This includes bronchogenic cysts, neurenteric cysts, lipomas, abscesses, and neurogenic tumors such as neurofibromas, schwannomas, and paragangliomas (16).