대한흉부영상의학회 Korean Society of Thoracic Radiology

Discussion

Diagnosis With Brief Discussion

Diagnosis

Esophageal Leiomyoma, Incidental Right aortic arch with aberrant left subclavian artery

Radiologic Findings

PA chest radiograph shows incidental right-sided aortic arch. Another finding is a large ovoid mass shadow in the superior mediastinum. Post-contrast CT scans show a large, well-defined, homogenous, low-attenuation mass in the middle mediastinum. Punctate calcification is seen within the mass. Esophageal lumen is collapsed due to the mass effect (circumferential sweeping of esophageal gas). Chest PA and 2D-coronal reformatted image show the longitudinal growth of the mass along the esophagus. There is incidental right aortic arch and aberrant left subclavian artery.

DDx.
1. Esophageal leiomyoma
2. Neurogenic tumor originated from vagus nerve, or plexiform neurofibromatosis
3. Thrombosed aneurysm of the aberrant left subclavian artery
4. Pseudoaneurysm of aberrant left subclavian artery
5. Other mediastinal tumors

Brief Review

The esophageal leiomyoma accounts for 45 to 73 per cent of all benign esophageal tumors. Most frequently, esophageal leiomyomas occur in the lower third of the esophagus (60%) and are detected in early or middle adult life. Most leiomyomas are solitary tumors, but occasionally multiple tumors are present. Smooth muscle tumors (leiomyomas and leiomyosarcomas) may grow to a substantial size without causing dysphagia and therefore may first appear as an asymptomatic mediastinal mass. Diagnosis by esophagography is usually straightforward; an intramural lesion producing a smooth crescent-shaped defect in the barium column. Now CT often is performed without preliminary barium swallow. CT shows a smooth, round, well-defined, enhancing mass, which may contain calcium, in the posterior mediastinum inseparable from the esophagus. The esophagus is usually not dilated above the level of the tumor. This lack of dilatation can be an important differential diagnostic point in reducing the likelihood of carcinoma of the esophagus. Preservation of adjacent fat planes and calcification also help to distinguish a benign leiomyoma from a carcinoma. Histologically, these tumors consist of intersecting bands of smooth muscle and fibrous tissue in a well-defined capsule. Unlike gastric leiomyomas, however, esophageal leiomyomas rarely undergo ulceration, so upper gastrointestinal bleeding is extremely uncommon. About 60% of these lesions are located in the distal third of the esophagus, 30% in the middle third, and 10% in the proximal third. Leiomyoma are less common above the level of the aortic arch because of the presence of striated rather than smooth muscle in this portion o the esophagus. These tumors appear grossly as discrete submucosal masses, usually ranging from 2 to 8 cm in size. Occasionally, however, the lesions may have an exophytic, intraluminal, or circumferential growth pattern.

References

1. Moersch H, Harrington SW. Benign tumors of the esophagus. Ann Otol 1944;53:800
2. Godard JE, McCranie D. Multiple leiomyomas of the esophagus. AJR 1973;117:259
3. Cohen AM, Cunat JS. Giant esophageal leiomyoma as a mediastinal mass. J Can Assoc Radiol 1981;32:129-130
4. Seremetis MG, Lyons WS, Deguzman VC, et al. Leiomyomata of the esophagus: an analysis of 838 cases. Cancer 1976;38:2166-2177

Keywords

Esophagus, Benign tumor, Esophageal Leiomyoma, Incidental Right aortic arch with aberrant left subclavian artery