Benign tumors of the esophagus are rare lesions that constitute less than 1% of esophageal neoplasms. Nearly two thirds of benign esophageal tumors are leiomyomas; the others mostly are polyps and cysts. Thus, leiomyomas are the most common benign tumors of the esophagus.[1]
Leiomyomas represent a hyperproliferation of interlacing bundles of smooth muscle cells that are well-demarcated by adjacent tissue or by a smooth connective tissue capsule. They usually arise as intramural growths, most commonly along the distal two thirds of the esophagus. They are multiple in approximately 5% of patients.
The majority of leiomyomas have been discovered incidentally during evaluation for dysphagia or during autopsy. Bleeding rarely occurs in cases of benign disease but typically is observed with leiomyosarcoma, the malignant counterpart of this tumor. The potential for malignant degeneration of leiomyomas is extremely small. In the distal esophagus, leiomyomas may reach large proportions and may encroach on the cardia of the stomach.
In a retrospective review of the Cleveland Clinic pathology database, Jiang et al investigated the clinicopathologic features of esophageal leiomyomas. Analyzing 30 cases from 28 patients, the investigators found mean tumor sizes among symptomatic and asymptomatic patients to be 5.2 cm and 0.4 cm, respectively. In symptomatic patients, the most common complaint was dysphagia (71.4%). The majority of esophageal leiomyomas (69%) were found in the distal and middle thirds of the esophagus, with most (69.6%) developing from the muscularis propria layer. For the most part, the tumors were made up of bland spindle cells with low cellularity and lacked both nuclear atypia and mitotic activity; cells were found to be positive for smooth muscle actin and negative for the CD34 and CD117 proteins. Among the 22 patients (78.6%) for whom follow-up information was available, no leiomyoma-related adverse events were found.[1]
Esophageal leiomyomas comprise less than 0.6% of all esophageal neoplasms, both in the United States and worldwide.
Esophageal leiomyomas typically occur in individuals aged 20-50 years.
No known sex or race predilection is recognized.
Esophageal leiomyomas rarely cause symptoms when they are smaller than 5 cm in diameter. Large tumors can cause dysphagia, vague retrosternal discomfort, chest pain, esophageal obstruction, and regurgitation. Rarely, they can cause gastrointestinal bleeding, with erosion through the mucosa.
Other than the nonspecific symptoms associated with esophageal leiomyomas, very few physical findings are ever noted. In extremely rare cases where severe esophageal obstruction is caused by a leiomyoma, weight loss and muscle wasting may be observed.
Esophageal leiomyoma can be visualized using barium swallow. The classic appearance is a smooth concave mass underlying intact mucosa. Distinct sharp angles are seen at the junction of the tumor and normal tissue. Encroachment onto the esophageal lumen usually is observed.
Esophageal ultrasonography can be helpful in demonstrating a smooth, typically round, mass located in the muscularis without encroachment into the overlying mucosa or underlying adventitia.
Esophagoscopy may reveal a nonspecific tumor in the wall of the esophagus, typically without mucosal involvement (ulceration or erosion).
Upon endoscopy, the lesions are identified as mobile submucosal masses.
Esophagoscopy should be performed to rule out carcinoma. It is important to remember that if a leiomyoma is suspected at esophagoscopy, a biopsy should not be performed if it would cause scarring at the biopsy site, which would hamper definitive extramucosal resection at surgery. A brush cytology may be performed. A leiomyoma (especially an ulcerated one) routinely is biopsied through the endoscope without any problems occurring in the ability to resect at a later date. In fact, an ulcer in a leiomyoma may be considered much worse than a mucosal biopsy.
Esophageal ultrasonography has aided in the diagnosis of leiomyomas, which demonstrate a homogeneous region of hypoechogenicity juxtaposed with the overlying mucosa.
Endoscopic ultrasonography is a useful technique for diagnosing and reaching treatment decisions for esophageal leiomyoma.[5]
Histologically, the tumors are comprised of bundles of interlacing smooth muscle cells, well-demarcated by adjacent tissue or by a definitive connective tissue capsule. They are composed of fascicles of spindle cells that tend to intersect with each other at varying angles. The tumor cells have blunt-ended elongated nuclei and show minimal atypia with few mitotic figures.
Surgical excision is recommended for symptomatic leiomyomas and those greater than 5 cm. Asymptomatic or smaller lesions should be followed periodically with barium swallow.
Resection is the only way to confirm that a tumor is not malignant. Periodic follow-up of smaller lesions is recommended because leiomyomas have a characteristic radiographic appearance, slow growth rate, and low risk of malignant degeneration. Tumors of the middle third of the esophagus are approached using a right thoracotomy; tumors in the distal third of the esophagus are resected through a left thoracotomy.
The outer esophageal muscle is gently incised longitudinally in order to reveal the lesion. Careful dissection is performed to separate and remove the leiomyoma from the underlying submucosa.
If the mucosa has been opened during dissection, the underlying mucosa is reapproximated, followed by closure of the longitudinal muscle. Some authors have shown that large extramucosal defects may be left open without subsequent complications developing.
Segmental esophageal resection may be indicated for giant leiomyomas of the cardia.
While open surgical technique is the traditional mainstay of therapy for leiomyomas, combined esophagoscopy and video-assisted resection (thoracoscopy) or laparoscopic transhiatal resection are being increasingly performed.[6, 7, 8, 9]
Endoscopic removal of these tumors has been attempted, but this technique cannot be considered standard of care.
However, a retrospective study by Wang el al indicated that endoscopic submucosal tunnel dissection (ESTD) is a safe and effective treatment for esophageal leiomyoma and that it has advantages over endoscopic submucosal dissection (ESD). The study involved 39 patients who underwent resection for leiomyoma, either by ESTD or ESD. Compared with ESD, ESTD was associated with shorter operating times, hospital stays, and time needed for incision healing. Moreover, the ETSD and ESD groups showed no significant difference in the incidence of complications.[10]