Type:
Educational Exhibit
Keywords:
Gastrointestinal tract, Thorax, CT, Diagnostic procedure, Cancer, Infection, Inflammation
Authors:
M. B. Barrio Piqueras, C. Urtasun Iriarte, M. Jiménez Vázquez, C. Mbongo, J. C. Pueyo, J. C. Larrache Latasa, G. Bastarrika Alemañ, A. Ezponda Casajús
DOI:
10.26044/ecr2023/C-13018
Findings and procedure details
Many esophageal lesions are incidentally detected on chest CT. In general, when esophageal pathology is suspected, CT should be performed with both oral and intravenous contrast. CT also allows to evaluate the wall thickness of the esophagus and the presences of associated mediastinal involvement.
- Esophageal anatomy and histology
- The esophagus is divided into 3 anatomic regions: cervical, thoracic, and abdominal[1].
- The cervical esophagus is bordered anteriorly by the trachea, posteriorly by the prevertebral fascia, and laterally by the carotid sheds and the thyroid gland.
- The thoracic esophagus extends from the thoracic inlet to the diaphragmatic hiatus. The esophagus is anteriorly related to the the trachea and posteriorly to the prevertebral fascia. It descends posterior to the aortic arch and lies to the right of the descending aorta and posterior to the right of the subcarinal lymph nodes and the pericardium. Two physiologic points of esophageal narrowing: cricoid cartilage and diaphragm: common points of impactation.
- 4 layers: mucosa, submucosa, muscularis propria, and adventitia. The esophagus is not covered by serosa.
- Benign esophageal disorders[2]:
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- Benign esophageal tumors[3](<1% of esophageal neoplasms).
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- Leiomyoma (>50% of benign tumors) consists of intersecting bands of muscle and fibrous tissue in a well-defined capsule. Almost 2/3 are in the distal third. Usually asymptomatic, the most common symptom is dysphagia. These tumors show a low growing rate. At chest-CT, they appear as homogeneous, oval-shaped, well-defined submucosal soft tissue lesions. Calcifications are characteristic[4].
- Fibrovascular polyps are rare intraluminal submucosal tumor-like lesions. They are usually pedunculated, intraluminal mass with outstanding growth.
- Esophageal schwannomas are very rare lesions, typically located in the upper esophagus an in middle-aged women. Schwannomas do not show distinctive radiological characteristics. They appear as homogeneous and low attenuated lesions with smooth border.
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- Congenital lesions:
- Duplication cysts (20 % of all gastrointestinal tract duplications)[5]. Most of them are asymptomatic and do not communicate with the esophageal lumen. CT typical feature consists of a low-attenuation homogeneous mass with a smooth border.
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- Esophageal diverticula develop either by pulsion (increased intraluminal pressure) or by traction (fibrosis in adjacent periesophageal tissue). On CT, pulsion diverticula have a round contour and wide neck and only consist of mucosa. According to their location, three types of diverticula should be considered:
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- Pharyngoesophageal junction: Zenker diverticula (pulsation type) usually arise from the upper third of the esophagus near the cricopharyngeal muscle.
- Middle esophagus: traction type.
- Distal esophagus: epiphrenic diverticulum (pulsation type).
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- Infectious diseases[6]: On CT, a frequent finding is a circumferential wall thickening (>5mm) with a long segmental involvement. Enhancement of internal mucosa (target sign) is typical. CT features of these entities are non-specific. Etiology must be determined depending on patient´s characteristics/status and endoscopic findings. Among them, Candida esophagitis is the most common infection of the esophagus. It is usually found in immunocompromised patients (underlying malignancy, radiation, steroids, AIDS…). Other esophagitis can be secondary to herpes simplex virus, cytomegalovirus and human immunodeficiency virus.
- Chagas disease is a tropical parasitic infection which can affect the esophagus, presenting a characteristic luminal dilatation (megaesophagus).
In acute Chagas cardiomyopathy, pericardial effusion may be present. Differential diagnosis with achalasia should be done.
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- Inflammatory disorders
- Reflux esophagitis and Barrett’s esophagus[7]: Gastrointestinal reflux disease (GERD) develops when reflux of gastric contents causes symptoms, esophageal injury or both. The most typical symptoms are pyrosis and regurgitation. The most frequent cause is lower esophageal sphincter dysfunction. When a patient over 50 presents with GERD, an endoscopy is usually performed due to the higher prevalence of Barrett´s esophagus and adenocarcinoma. In CT GE reflux can be inferred when contrast material is observed in the esophageal lumen. Barrett’s esophagus has a prevalence of 3-15% in patients with esophagitis due to metaplasia of esophageal squamous cell epithelium to columnar epithelium. Reflux esophagitis, a complication of GERD, can manifest as mural thickening and edema of the esophagus.
- Eosinophilic esophagitis(EoE): Dysphagia and food impactation may be found. CT shows nonspecific esophageal edema. Typical endoscopic findings in EoE include edema and concentric rings (“trachealization”).
- Radiotherapy-induced esophagitis[8] can be found when the esophagus is included in the radiation field in the treatment of intra-thoracic malignancies. Acute phase occurs during treatment and resolves within 4-6 weeks after ending radiotherapy. Symmetric esophageal wall thickening extending along the irradiated esophagus is commonly seen in acute and chronic esophagitis. In the chronic stage is possible to find strictures due to fibrosis.
- Scleroderma[3] consists of a dilatation of the esophagus in relation with impaired microvasculature that leads to neuronal injury. It causes hypoperistalsis and loss of LES tone, a situation that leads to reflux esophagitis and stricture formation.
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- Traumatic
- Esophageal impactation[9]: commonly seen in emergency departments, typically resolves spontaneously. CT appearance of foreign body impactation is variable, depending on the object ingested, the site and the presence of an underlying pathologic process. Complications include perforation or pressure necrosis.
- Hematoma[9]: An intramural hematoma may occur spontaneously or in association with traumatic esophageal dissection. At CT, it is possible to appreciate an eccentric hyperattenuating mass within the wall of the esophagus.
Symptoms may mimic acute myocardial infarction or aortic dissection.
- Perforation: Serious event that could lead to fulminant mediastinitis. 75% of them are caused by endoscopic procedures. Other causes are related to foreign bodies and penetrating trauma. Spontaneous perforation due to a sudden increase of intraluminal esophageal pressure is called Boerhaave syndrome. Extraluminal gas in the mediastinum is suggestive of esophageal perforation.
- Esophageal-airway fistula[2]: They could occur as complications of tumors, infections, iatrogenic or trauma. On CT, it is possible to appreciate free transition of air from the trachea to the esophagus.
- Esophageal mediastinal fistula is also a possible finding.
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- Achalasia[2] originates due to a failure of organized esophageal peristalsis, causing impaired relaxation of the lower esophageal sphincter. CT shows a moderate to marked esophageal dilatation. Complications include pulmonary aspiration and secondary carcinoma. Differnential diagnosis with nutcraker esophagus should be suggested.
- Acute esophageal necrosis(AEN): extremely rare entity. On endoscopy, it is characterized by diffuse and circumferential involvement of a black-appearing distal esophagus, with preservation of the gastroesophageal junction(GEJ). Signs of upper gastrointestinal bleeding are common. Chest-CT is useful for the evaluation of possible complications, including perforation, pneumomediastinum, and mediastinitis. Small air-bubbles can be seen within a thickened wall. Dilatation of the esophagus can also be observed.
- Hiatal hernia[2]: sliding (99%) or para-esophageal. In CT it appears as a dilatated distal esophagus and a superior displacement of the stomach above the diaphragm.
- Esophageal and para-esophageal varices: the most common cause is portal hypertension. Enhanced-CT reveals sinuous enhancing structures in the esophageal wall.
- Primary malignant esophageal tumors[10] account for 80% of esophageal neoplasms including adenocarcinoma, lymphoma, squamous carcinoma, and primary malignant melanoma. Esophageal metastases can also be detected. CT plays an important role in the evaluation of mediastinal invasion and detection of metastases.
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- Squamous carcinoma(SCC) is a malignant tumor of epithelial cells with stratified squamous differentiation. Tobacco and alcohol use are major risk factors. Progressive dysphagia and weight loss are common symptoms. Most SCCs involve the middle third of the esophagus. At CT, it is possible to find localized thickening (asymmetric or circumferential) of the esophageal wall or a soft tissue mass.
- Adenocarcinoma: most of them arise from malignant degeneration of underlying Barrett epithelium. Symptoms are like those of the SCC. Adenocarcinoma may be indistinguishable from SCC at imaging, but most adenocarcinomas involve the lower third of the esophagus and are more likely to invade the stomach.
- Lymphoma: usually results from direct extension of lymphoma to the esophagus. Primary lymphoma is extremely rare. Although dysphagia is a common symptom, many patients remain asymptomatic. CT findings, non-specific, include concentric or asymmetric thickening of the esophageal wall. The presence of an intact fat plane between the esophagus and neighboring structures supports the diagnosis of esophageal lymphoma.
- Primary malignant melanoma of the esophagus could appear as a polypoid or bulky intraluminal contrast-enhancing mass compressing the adjacent structures.