While generally rare, benign esophageal lesions (e.g., tumors, polyps, or cysts) are of concern because they have the ability to impede the passage of food and, if partially obstructing, can increase the risk of significant aspiration. As a rule, the surgical resection of these lesions is associated with low operative risk and low mortality and is curative in nature. Benign esophageal tumors often are classified in terms of their location (e.g., submucosal, intraluminal, or intramural) and commonly are aligned with specific patterns of presentation that aid diagnosis and, ultimately, management. The most common benign tumor of the esophagus is leiomyoma, which is typically intramural in location. Esophageal cysts are the second most common lesion, comprising approximately 20% of all benign processes. These include congenital and acquired lesions, which are either persistent vacuoles that remain within the esophageal wall during embryologic development or obstructions of the excretion ducts within esophageal glands. The former generally present in the early childhood years, whereas the latter present later in adult life. Intraluminal esophageal polyp is the second most common tumor. Granular cell myoblastoma and hemangioma round out the list of most common benign esophageal tumors, and these usually are classified as submucosal.

The location of the lesion generally is associated with the symptoms. Intraluminal lesions are often associated with dysphagia, vomiting, and poor oral tolerance, as well as cough, substernal distress, and aspiration. Intramural and submucosal lesions are often asymptomatic; however, it is also common to experience dysphagia with submucosal lesions. In general, the standard of care for treatment of benign esophageal tumors or cysts is surgical resection. Frozen biopsy should be performed on all lesions to ensure that the benign preoperative diagnosis is accurate.

INCIDENCE AND CLASSIFICATION

In a 30-year review of over 15,000 autopsies, Attah and Hajdu found only 26 cases of benign esophageal tumors, for a prevalence rate of 0.17%, although some have estimated the true incidence to be as high as 0.5% of the general population.¹ In the review by Attah and Hajdu, esophageal malignancies were noted to be about five times more common (n = 120). However, while benign tumors and cysts account for fewer than 2% of all esophageal lesions, they reportedly account for up to 10% of all surgically resected esophageal lesions.² Various classifications have been proposed for benign esophageal tumors. The more commonly used classifications are by histologic cell types or relative location within the esophageal wall (Table 39-1). In general, benign tumors of the esophagus are more common in men than in women and usually become symptomatic after the fourth decade.

Reproduced from reference 3 with permission.

Classification systems that are functionally oriented are based on location within the esophagus (e.g., intramural, submucosal, or intraluminal) and are useful clinically because they can be related to the specific presentation, diagnosis, and expected treatment. It is important to bear in mind that most lesions are asymptomatic. For those that produce symptoms, location within the esophageal wall is more closely aligned with the specific symptoms.

Intraluminal lesions, by definition, are more likely to project into the esophageal lumen, variably causing obstruction. Most common among these are the fibrovascular polyps, which account for a very small percentage of benign esophageal lesions and are more usually located within the upper third of the esophagus. Polyps begin as small lesions and often elongate, forming a pedunculated base. For larger lesions, patients often report dysphagia, vomiting, and weight loss; less commonly they report cough, substernal discomfort, and aspiration pneumonia. Given the higher degree of traction, highly vascular nature, and thin tissue that covers the lesion, local gastrointestinal bleeding has been reported. For lesions located submucosally or intramurally, the frequency of symptoms is lower. In the past, most such lesions were noted incidentally at the time of other interventions, but now they more commonly represent an incidental finding on unrelated imaging studies. Submucosal lesions are associated with dysphagia, which is not linearly associated with size. Additional symptoms include vague substernal discomfort and heartburn.

Esophageal cysts include congenital and acquired lesions and are secondary either to persistent vacuoles that remain within the esophageal wall during embryologic development or to obstruction of the excretion ducts within esophageal glands. Embryologically, the upper gastrointestinal tract develops from the posterior division of the primitive foregut. During the fourth week of gestation, the primitive foregut develops an anterior diverticulum. This becomes the respiratory bud. Meanwhile, the posterior division develops into the esophagus and upper gastrointestinal tract. The tracheoesophageal septum separates the primitive esophagus from the primitive trachea. As the esophagus continues to develop, the epithelium eventually obliterates the lumen and later recanalizes. As one might expect from the common embryologic origin, bronchogenic and esophageal cysts can occur together. Esophageal cysts develop from aberrant elements of the esophageal wall.

Simple cysts are duplications of the epithelium, whereas true esophageal duplications are duplications of the submucosa and the muscle wall but do not involve the epithelium. Esophageal cysts and duplications do not usually communicate with the lumen of the esophagus. Esophageal cysts usually occur in the neck, chest, and abdomen. The former generally present in the early childhood years, whereas the latter present later in adult life. Furthermore, congenital cysts are classified as duplication cysts when they are (1) located within the esophageal wall, (2) have a lining of squamous epithelium or a lining consistent with the embryonic esophagus, and (3) are covered by two muscle layers. Both types tend to be located in the upper third of the esophagus. In either situation, the cystic lesions accumulate mucus material over time and gradually increase in size. When they have obtained sufficient size, they may cause partial obstruction and symptoms as noted earlier. In addition, symptoms associated with these cysts can include recurrent respiratory infections owing to aspiration from a leaking cyst. Furthermore, the location of the cyst in the upper esophagus allows for potential compression of the airway with associated respiratory embarrassment or dyspnea on exertion if the size is significant or the location specific.

In general, most benign esophageal tumors and cysts are located in the middle and lower thirds of the thoracic esophagus. Leiomyoma is the most commonly described lesion and constitutes 65% of all benign lesions of the esophagus. Cystic lesions are the second most common and comprise nearly 20% of lesions. Polypoid lesions are the next most common, accounting for an additional 5% of lesions, and the remaining 10% are a diverse collection of several lesions, including hemangioma, granular cell myoblastoma, lipoma, and adenoma, among others.

DIAGNOSIS

Since most benign esophageal lesions are asymptomatic, there has been a wide description of techniques that, to some degree, are able to characterize these lesions. Diagnostic evaluation of patients who are symptomatic is a combination of direct inspection aligned with radiographic and ultrasonic interrogation. The vague nature of some of the symptoms associated with these lesions often leads to a chest radiograph, but plain films of the chest have not been shown to be highly diagnostic, except in the case of a large leiomyoma that has calcified. Most of these lesions can be appreciated on CT scan, with and without contrast material, once they have achieved suitable size and endoluminal girth. This modality also helps to define whether the lesion is cystic or solid. Barium esophagography is often diagnostic of these lesions not only by the location and nature of luminal disruption but also because it lends to the definition of any associated motility issues. Esophagoscopy is a mandatory part of any tumor evaluation. Use of endoscopic ultrasound has greatly extended the utility of endoscopic evaluation. Ultrasound permits better definition of the margins of the lesions as well as the character (cystic versus solid) and can guide biopsy for diagnosis when ruling out a nonbenign etiology.

SURGICAL TECHNIQUE

Submucosal Resection

Patients identified for resection of a benign esophageal tumor undergo standard preoperative evaluation to confirm the patient's thoracic surgical candidacy and to evaluate comorbid disease and define operative risk. This evaluation was described earlier in Chapter 4. Since most benign esophageal tumors occur in the middle to distal third of the esophagus, the surgical approach is most often via the right hemithorax. Identifying the exact anatomic location of the lesion is critical because the approach may be altered on the basis of specific anatomic variations or concurrent issues. Traditionally, thoracotomy has been the preferred route to resection of these benign esophageal lesions. However, with increasing experience within the thoracic surgical community, surgeons are commonly using minimally invasive techniques for treatment. Video-assisted thoracic surgery, thoracoscopy, and laparoscopy, with or without endoluminal guidance (i.e., esophagoscopy and transillumination) in the lateral decubitus and semiprone positions all have been used to facilitate submucosal resection or enucleation; despite seemingly different surgical approaches, the techniques of actual resection are nearly identical. Thoracotomy for exposure is now generally used for lesions greater than 5 cm in length, although in experienced hands these lesions can be resected with a modified minimally invasive technique.

Perioperative antibiotics are administered after appropriate site verification and surgical "time out." Lung isolation as part of the general anesthetic plan is often used and helpful, although not mandatory. Use of double-lumen endotracheal intubation or a bronchial blocker device does significantly improve operative visibility and ease of exposure, as described earlier in Chapter 5. Appropriate positioning and draping are important in the planning to permit the most effective vectors for minimally invasive approaches. Exposure of the esophagus is achieved. Palpation to determine the exact location of the lesion either physically or endoscopically is undertaken. To aid in localization of the lesion, the flexible gastroscope (inserted into the esophagus before patient positioning) is advanced in the esophagus to the proximal extent of the lesion. Insufflation is not continued after gastroscope positioning. Transillumination with the gastroscope or palpation of the gastroscope with a surgical instrument identifies the vicinity of the lesion. Mobilization of adhesions and normal anatomic barriers is undertaken, including mobilization of the inferior pulmonary ligament. The parietal pleura is divided longitudinally over the level of the esophagus of interest. This can be performed as a single incision but may require division anteriorly and posteriorly to the esophagus to facilitate more extensive esophageal (circumferential) mobilization when required owing to the size or exact location of the tumor. Division of the overlying tissue as well as the parietal pleura also improves transillumination and may help to more precisely define the location and extent of the tumor (Fig. 39-1).

Once the extent of the tumor mass is identified, the parietal pleura is gently but bluntly mobilized away from the underlying esophageal musculature. If the parietal pleura is divided in an area overlying the mass directly, then a single incision is used for both the parietal pleura and the underlying esophageal muscle. The muscle fibers are scored longitudinally and then gently divided or bluntly separated in a similar fashion, thereby exposing the submucosal mass (see Fig. 39-1, inset A, B ). The length of division of the esophageal muscle layer required for exposure is generally less than the length of the tumor itself. Transillumination at this step clarifies the muscle layer thickness and assists with mass identification.

Next the esophageal muscle layer is bluntly mobilized from the tumor mass in all directions. Exposure is gained to the edge of the tumor pseudocapsule. This is grasped, and both scissor dissection and blunt dissection are used to mobilize the tumor from the underlying mucosal layer. Electrocautery is useful but should be used sparingly to avoid local tissue injury and mucosal necrosis. The in situ gastroscope can be used to provide suction to the esophageal mucosa at this point, moving it away from the tumor mass. Alternatively, gastroscopic visualization of the mucosa can be used during this portion of the dissection to confirm a lack of violation of the esophageal mucosa.

The tumor is removed from the hemithorax without manipulation or inadvertent morselization of the tumor. Use of a bag or similar retaining device is advisable to avoid possible contamination of the thorax. Hemostasis is achieved. Insufflation via gastroscope in the area of the resected tumor is carried out to help rule out any unappreciated perforation of the esophageal mucosa. Occlusion of the esophagus distal to the resection site may help in this maneuver and usually can be accomplished using compression of the distal esophagus with a sponge stick. Evaluation of mucosal integrity is done under irrigation to improve the sensitivity of this test. After mucosal integrity is confirmed, the esophageal muscle layer is meticulously reapproximated without tension. Although multiple techniques can be used, we recommend an interrupted closure with slowly absorbable suture (see Fig. 39-1 inset C ).

A healthy-appearing well-approximated esophageal muscle closure for uncomplicated enucleation of a small, benign esophageal tumor requires no routine buttressing or relaxation incision. If resection of associated muscle fibers or thinning of muscle fibers (owing to the tumor) results in closure of the esophageal muscle under tension, then a relaxing myotomy can be created on the esophagus directly opposite the side of tumor resection. Rarely, a local tissue flap of pleura, pericardium, or diaphragm or a pedicle muscle (intercostal) or omental flap can be used to buttress or at times augment the muscle layer closure.

Insertion of a nasogastric tube, if desired, can be performed under gastroscopic guidance to ensure an uncomplicated passage through the esophagus. The surgical bed and hemithorax generally are drained; the drain is placed in proximity to, but not directly over, the surgical resection site. Intravenous proton pump inhibitors or H₂-blockers are used to minimize reflux, particularly when the tumor approaches the lower esophageal sphincter.

Postoperative care is standard. The patient generally can be started on an oral clear liquid diet on the first postoperative day. Alternatively, an esophagram can be obtained to confirm mucosal integrity before an oral diet is begun. Depending on the patient's tolerance, the diet is advanced to a pureed or mechanical soft diet for several days and then is slowly liberalized. Oral medications are given in a liquid form, if possible, and large-caliber pills are avoided.

Resection of Endoluminal Tumors

Small and pedunculated intraluminal tumors may be suitable for endoscopic resection, provided that the stalk is narrow and not particularly vascular. Lesions that are vascular, more broadly based, or have high cervical attachments should be approached via thoracotomy or video-assisted thoracic surgery. Once the lesion is mobilized, a contralateral counterincision should be made in the normal esophagus. The base of the lesion can either be oversewn, suture-ligated, or resected with the bed closed in layers.

Segmental Resection

Segmental resection of benign esophageal tumors is an uncommon procedure, especially in adults, and is performed most often for tumors that involve the esophagus circumferentially or the esophageal muscle layer or mucosa in such a way that precludes submucosal resection. Often a decision to perform a segmental resection of the esophagus is made after submucosal resection is determined to be inappropriate or an attempt at submucosal resection has failed. The length of a successful segmental resection of the esophagus can never be more than a few centimeters unless significant foregut mobilization is undertaken. Not all areas of the esophagus are amenable to segmental resection. As a consequence of these constraints, a formal esophageal resection with conduit reconstruction should be considered preoperatively in every case. Esophageal segmental resection can be used in esophageal trauma, acquired tracheoesophageal fistula, and esophageal stent removal. It has been described rarely for treatment of malignant esophageal tumors.

Perioperative antibiotics are administered after appropriate site verification and surgical "time out." Lung isolation as part of the general anesthetic is often used and helpful, although not mandatory. Use of double-lumen endotracheal intubation or a bronchial blocker device does significantly improve operative visibility and ease of exposure. Appropriate positioning and draping are important in the planning to permit the most effective vectors for minimally invasive approaches. Approach is generally via the right hemithorax for intrathoracic resection and through the left neck for cervical esophageal tumors. Exposure to the section of esophagus of interest is achieved. Palpation is used to determine the location of the lesion; this can be assisted endoscopically by positioning the gastroscope as described previously. Mobilization of the esophagus is carried out on the esophageal wall; this is generally performed with great care, either bluntly or sharply, to avoid injury to nearby structures, including the posterior membranous airway. Esophageal mobilization is essential to creating a tension-free segmental resection, which ultimately will determine the success of the operation. However, the need for adequate mobilization is balanced against the segmental blood supply of the esophagus, which must be diligently maintained wherever possible.

The proximal extent of the tumor is identified and confirmed (Fig. 39-2). The esophageal muscle layer is divided down to the mucosa using scissors with minimal electrocautery for hemostasis. The muscle fibers are retracted to better expose the mucosal layer. The esophagus proximal to the tumor is either clamped with an atraumatic bowel clamp or grasped laterally to prevent retraction, minimize spillage, and preserve orientation. The mucosal layer is divided sharply.

The distal extent of the tumor is identified, and division of the esophagus distal to the tumor is performed in the fashion described previously. The segmental resection specimen is removed. Hemostasis is achieved.

Reapproximation of the esophageal ends is performed in a manner analogous to small bowel resection or other gastrointestinal anastomosis. Full-thickness single-layer hand-sewn, two-layer hand-sewn, and stapled closures (partial or complete) with or without spatulation all have been used for esophageal anastomosis. The type of closure used will vary depending on location and patient specifics. However, a tension-free anastomosis is paramount to proper healing. A nasogastric tube generally is used for decompression and should be placed under direct observation. A muscle pedicle flap (i.e., intercostal for thoracic anastomosis and strap muscle for cervical anastomosis) or other vascularized flap often is used in a noncircumferential way to buttress the anastomosis. The postoperative care of the esophageal segmental resection patient is similar to that of the submucosal resection patient, except that the patient is kept nothing by mouth for several days until an intact anastomosis is confirmed by esophagram. Drainage of the area with a soft drain is commonplace.

Resection of Benign Esophageal Cysts

The technical aspects pertaining to resection of esophageal cysts are very similar to those of benign lesions; accordingly, the following description is simplified. Patients identified for resection of a benign esophageal cyst also should undergo standard preoperative evaluation to confirm the patient's thoracic surgical candidacy and to evaluate comorbid disease and define operative risk. This evaluation was described earlier. Since most benign esophageal cysts occur in the upper third of the esophagus, the surgical approach is most often via the right hemithorax. Identifying the exact anatomic location of the lesion is critical because the approach may be altered on the basis of specific anatomic variations or concurrent issues. While thoracotomy has been the traditional route, surgeons now commonly use minimally invasive techniques for treatment. Video-assisted thoracic surgery, thoracoscopy, and laparoscopy, with or without endoluminal guidance (i.e., esophagoscopy and transillumination), in the lateral decubitus and semiprone positions all have been used to facilitate submucosal resection or "enucleation"; despite seemingly different surgical approaches, the techniques of actual resection are nearly identical. Thoracotomy for exposure is now generally used for lesions greater than 5 cm in length, although in experienced hands these lesions can be resected with a modified minimally invasive technique.

Perioperative antibiotics are administered after appropriate site verification and surgical "time out." Lung isolation as part of the general anesthetic plan is often used and is helpful, although not mandatory. Use of double-lumen endotracheal intubation or a bronchial blocker device does improve operative visibility and ease of exposure significantly, as described in Chapter 5. Appropriate positioning and draping are important in the planning to permit the most effective vectors for minimally invasive approaches. Exposure of the esophagus is achieved. Palpation to determine the exact location of the lesion either physically or endoscopically is undertaken. To aid in localization of the lesion, the flexible gastroscope (inserted into the esophagus before patient positioning) is advanced in the esophagus to the proximal extent of the lesion. Insufflation is not continued after gastroscope positioning. Endoscopic ultrasound helps to confirm the diagnosis of a cystic lesion and can better define the functional edge of the cyst. Transillumination with the gastroscope or palpation of the gastroscope with a surgical instrument also can identify the vicinity of the lesion. Mobilization of adhesions and normal anatomic barriers is undertaken, including mobilization of the inferior pulmonary ligament. The parietal pleura is divided longitudinally over the level of the esophagus of interest. Division of the overlying tissue, as well as the parietal pleura, also improves transillumination and may help to more precisely define the location and extent of the cystic lesion.

Once the extent of the cystic mass is identified, the parietal pleura is gently but bluntly mobilized away from the underlying esophageal musculature. If the parietal pleura is divided in an area overlying the mass directly, then a single incision is used for both the parietal pleura and the underlying esophageal muscle. The muscle fibers are scored longitudinally and then gently divided or bluntly separated in a similar fashion, thereby exposing the submucosal mass. The length of division of the esophageal muscle layer required for exposure generally is less than the length of the tumor itself. Transillumination at this step clarifies the muscle layer thickness and assists with mass identification.

Next, the esophageal muscle layer is bluntly mobilized from the cystic mass in all directions. Exposure is gained to the edge of the cyst pseudocapsule, with caution not to rupture the cyst. This is grasped, and both scissor dissection and blunt dissection are used to mobilize the tumor from the underlying mucosal layer. Electrocautery is useful but should be used sparingly to avoid local tissue injury and mucosal necrosis. The in situ gastroscope can be used to provide suction to the esophageal mucosa at this point, moving it away from the cyst. Alternatively, gastroscopic visualization of the mucosa can be used during this portion of the dissection to confirm a lack of violation of the esophageal mucosa.

The cyst is removed from the hemithorax without manipulation or inadvertent puncture of the cyst. Use of a bag or similar retaining device is advisable to avoid possible contamination of the thorax because the cyst is likely to rupture when pulled through a trocar site. Hemostasis is achieved. Insufflation via gastroscope in the area of the resected lesion is carried out to help rule out any unappreciated perforation of the esophageal mucosa. Occlusion of the esophagus distal to the resection site may help in this maneuver and usually can be accomplished using compression of the distal esophagus with a sponge stick. Evaluation of mucosal integrity is done under irrigation to improve the sensitivity of this test. After mucosal integrity is confirmed, the esophageal muscle layer is meticulously reapproximated without tension. Although multiple techniques can be used, we recommend an interrupted closure with slowly absorbable suture.

A healthy-appearing well-approximated esophageal muscle closure for uncomplicated enucleation of a small, benign esophageal cyst requires no routine buttressing or relaxation incision. If resection of associated muscle fibers or thinning of muscle fibers (owing to the cyst) results in closure of the esophageal muscle under tension, then a relaxing myotomy can be created on the esophagus directly opposite the side of cyst resection. Rarely, a local tissue flap of pleura, pericardium, or diaphragm or a pedicle muscle (e.g., intercostal) or omental flap can be used to buttress or at times augment the muscle layer closure.

Insertion of a nasogastric tube, if desired, can be performed under gastroscopic guidance to ensure an uncomplicated passage through the esophagus. The surgical bed and hemithorax generally are drained; the drain is placed in proximity to, but not directly over, the surgical resection site. Intravenous proton pump inhibitors or H₂-blockers are used to minimize reflux, particularly when the tumor approaches the lower esophageal sphincter. Postoperative care is standard, as described earlier.

SUMMARY

Benign esophageal tumors and cysts are considered appropriate for surgical resection. While there are several families of lesions that present within the esophagus, they share a common location and often presentation. Most benign esophageal lesions are amenable to submucosal or similar resections. Thus segmental resection of the esophagus is rarely indicated. Meticulous attention to detail with good approximation of tissue planes and suitable drainage is often all that is needed for successful resection of these lesions.

EDITOR'S COMMENT

One challenge is the correct management of leiomyomas. When these lesions are small and stable they may be followed by serial CTs provided that the diagnosis has been confirmed by endoscopic ultrasound (EUS). Biopsy is occasionally helpful, but even fine needle aspiration (FNA) guided by EUS can lead to mucosal injury, which could predispose to fistula after surgical resection. The major consideration in managing leiomyomas is lesion size, since the risk of true malignancy with gastrointestinal stromal tumors (GIST) increases with size. Complete resection is recommended and can be accomplished by means of enucleation. The procedure can be performed thoracoscopically or laparoscopically depending on location. Tumors located in the GE junction can be particularly extensive. For such cases, the patient and surgical team must be prepared to proceed with a partial esophagectomy if the lesion is malignant. For benign lesions, a Nissen or Dor fundoplication is occasionally needed to prevent reflux that sometimes results from the dissection of hiatal structures.

–RB

REFERENCES