대한흉부영상의학회 Korean Society of Thoracic Radiology

Discussion

Diagnosis With Brief Discussion

Diagnosis

Achalasia

Radiologic Findings

Initial chest radiograph shows a huge mass shadow in right paracardiac area.
The right heart silhouette remains intact in face of the mass shadow, suggesting that the mass is located in the posterior mediastinum.
Chest radiograph obtained six days later shows the mass shadow has decreased markedly in extent.
Contrast-enhanced CT scan obtained at gastroesophageal junction level (below) shows markedly dilated esophagus with mild diffuse wall thickening.
Esophagogram (below) shows markedly distended esophageal lumen with abrupt but smooth tapering at gastroesophageal junction level (terminal beak sign, arrow).
There was no evidence of malignancy on surgery.

Brief Review

Achalasia (megaesophagus) is derived from failure of relaxation at level of lower esophageal sphincter and organized peristalsis.
Of the several causes of dilatation of the esophagus-inflammatory stenosis (secondary to mediastinitis or reflux esophagitis), progressive systemic sclerosis (PSS), carcinoma, and achalasia-- the last causes the most severe generalized dilatation.
The abnormality is apparent as a shadow projecting entirely to the right side of the mediastinum.
Since it is behind the heart, it does not cause a silhouette sign with that structure.
The trachea may bulge anteriorly, and an air-fluid level may be observed in the dilated esophagus, most frequently in achalasia and seldom in PSS.
On conventional chest radiographs, air also may be identified in the esophagus in some patients postoperatively in laryngectomy patients who employ esophageal speech.
Symptoms of achalasia include dysphasia, pain on swallowing, and chronic cough and recurrent pneumonia due to aspiration.
According to Rabushka et al. who retrospectively reviewed CT scans of nine achalasia patients, CT finding was moderate to marked esophageal dilatation (mean diameter 4.35 cm at carinal level) with normal wall thickness. Complications in the patients with proven achalasia included secondary carcinoma (one), iatrogenic esophageal perforation (one), and pulmonary aspiration (three).
Computed tomography may not be indicated as a routine study, but in complicated cases CT may be invaluable in confirming the diagnosis or in detecting atypical features that may indicate the presence of other diseases or superimposed benign or malignant processes.

References

Fraser RS, Pare JAP, Fraser RG, Pare PD. Synopsis of diseases of the chest. 2nd ed. Philadelphia; W. B. Saunders. 1994:938
Rabushka LS, Fishman EK, Kuhlman JE. CT evaluation of achalasia. J Comput Assist Tomogr 1991;15(3):434-9

Keywords

Esophagus, Congenital,