Applied Radiology

Diagnosis

MULTINODULAR LEIOMYOMA (12 x 8 x 6 cm) encasing the lower end of the esophagus. The esophageal mucosa is free of tumor

Findings

Figure 1A. Posteroanterior chest film shows a mass in the medial portion of the left hemithorax adjacent to the esophagogastric junction. Figure 1B. In this lateral chest film, an mass is apparent in the region of the esophagogastric junction. Figure 2. In this contrast-enhanced CT of the chest and abdomen, a large, low-attenuation mass, can be seen intimately associated with and causing mass effect upon the mid and distal esophagus, and extending into the region of the gastric cardia. The mass measures 7.5 cm x 6 cm in greatest transverse and AP diameter respectively. Figure 3. This photograph shows two separate lobulations of the mass that was obtained from the esophagogastic junction. At pathologic analysis, the lobulations were very close and nearly contiguous to on another but were thought to represent two separate masses. A distinction between the two mass lesions was not made on the preoperative CT.

Discussion

Leiomyomas (LM) are the most common benign neoplasm of the esophagus, accounting for 60-70% of all benign esophageal neoplasms. Leiomyomas are of smooth muscle origin and can be found anywhere in the gastrointestinal tract. In the esophagus, they are most often located intramurally, although polypoid forms have been reported (1). An annular configuration of the intramural form has been noted in multiple patients (1,2). In symptomatic patients with leiomyomas, dysphagia is the most common symptom, followed by pain. Other symptoms include weight loss, gastrointestinal bleeding, passive regurgitation, nausea, and vomiting (1,2). In this case, the patient was asymptomatic and his mass was discovered incidentally, which is not uncommon with esophageal leiomyomas. Approximately 49% of LM's are less than 5 cm in size, with another 31% being between 5 and 9 cm (1). Several cases of giant leiomyomas up to 20 cm have also been reported (2). The peak incidence of LM's is betweend 30and 59 years, although they can occur at any age. The prevalence is nearly twice as high in males; the male to female ratio is 1.93:1.00 (1). LM's occurred most commonly in the lower third of the esophagus and multiple LM's have been reported as well (1,2). The preoperative diagnosis of a leiomyoma is difficult given the rare occurrence of these neoplasms, and the few pathognomonic findings. Diagnostic imaging utilized in the workup of these patients includes plain films, upper GI, CT, and endoscopic ultrasound. Endoscopy and biopsy are also routinely performed (1). On chest radiographs, a mediastinal mass may be noted, as was the situation in this case (figures 1A and 1B). Leiomyomas may contain amorphous areas of calcification, and a calcified esophageal mass should strongly suggest the diagnosis of a leiomyoma (3). On barium studies, leiomyomas generally appear as submucosal masses which may compress the esophageal lumen (2). Typical endoscopic ultrasound findings include a hypoechoic submucosal tumor with a smooth contour. On CT, leiomyomas tend to appear as homogenous, smoothly marginated, muscle density masses that routinely enhance (2,3). In this case, the CT findings are atypical. The esophageal mass is very low density, without evidence of contrast enhancement, and is circumferential (figure 2). Additionally, it was discovered on resection that what was initially interpreted as one large mass was actually two masses in close proximity (figure 3). It is both the atypical CT findings and the inability of the CT to distinguish between the two masses that make this case reportable. Other differential considerations at the time included fibroma, lipoma, lymphoma, and an atypical foregut duplication cyst. Leiomyosarcoma is the malignant equivalent of a leiomyoma. Although a few cases of malignant transformation have been reported, most cases of leiomyosarcoma appear to develop de novo. The CT appearance of leiomyosarcomas demonstrate masses to be larger, less uniform in shape, and variably attenuating in comparison to leiomyomas (1,3). After this patient underwent a CT examination, an endoscopic ultrasound and biopsy were performed. The results of which showed fibrous and cellular tissue consistent with a leiomyomatous process. Given the large size of the mass, and concern for possible sarcomatous involvement the patient then had a thoracotomy with resection of the mass. After resection and pathologic examination of the entire mass the characteristics were found to be most consistent with a leiomyoma.

1. Hatch GF III, Wertheimer-Hatch L, Hatch KF, et al. Tumors of the esophagus. World Journal of Surgery 24:401-411, 2000. 2. Gore RM, Levine MS, Laufer I. Textbook of Gastrointestinal Radiology. Volume 1:391-393, 2000. 3. Megibow AJ, Balthazar EJ, Hulnick DH, et al. CT evaluation of gastrointestinal leiomyomas and leiomyosarcomas. AJR 144:727-731, April 1985.