Esophageal rings and webs

INTRODUCTION — 

Esophageal rings and webs are thin structures that partially occlude the esophageal lumen. Patients with esophageal rings or webs are usually asymptomatic. Symptomatic patients typically present with intermittent dysphagia to solids. This topic will review the pathogenesis, clinical manifestations, diagnosis, and treatment of esophageal rings and webs. The approach to patients with dysphagia and esophageal strictures is discussed elsewhere. (See "Approach to the evaluation of dysphagia in adults" and "Endoscopic interventions for nonmalignant esophageal strictures in adults".)

ANATOMY — 

Nonpathologic indentation of the distal esophagus may be caused by esophageal A and B rings and the crural diaphragm.

●A ring – The A ring is caused by normal smooth muscle contraction in the esophagus located in the distal esophagus just proximal to the squamocolumnar junction corresponding to the strongest part of the lower esophageal sphincter.

●B ring – The B ring is a mucosal structure located precisely at the squamocolumnar junction that is smooth and thin (≤5 mm in axial length). Owing to its location, a B ring is covered with squamous mucosa proximally and columnar epithelium distally [1].

●Diaphragmatic impression – Indentations in the most distal esophagus or proximal stomach that are the result of extrinsic compression by the crural diaphragm [2]. The size of a sliding hiatal hernia is measured during a barium swallow x-ray from the diaphragmatic impression to the A ring; this is considered abnormal when it exceeds 2 to 3 cm. When less than 2 to 3 cm, it is a normal physiologic structure known as the phrenic ampulla.

TERMINOLOGY

●Esophageal web – An esophageal web is a thin (<2 mm) eccentric membrane that protrudes into the esophageal lumen. Esophageal webs are covered with squamous epithelium and most commonly occur anteriorly in the cervical esophagus, causing focal narrowing in the postcricoid area (image 1).

●Esophageal ring – The term esophageal ring refers to a concentric (2 to 5 mm) diaphragm of tissue that protrudes into the esophageal lumen. They are typically located in distal esophagus but can occur in other parts of the esophagus. Esophageal rings are usually mucosal but in rare cases may be muscular due to hypertrophy of an A ring. Schatzki ring, the most common type of esophageal ring, is a narrow mucosal B ring that is less than 12.5 mm in inner diameter [1]. (See 'Anatomy' above.)

EPIDEMIOLOGY — 

The true prevalence of esophageal rings and webs is unclear as most patients are asymptomatic. Esophageal B rings are found in 6 to 14 percent of routine barium esophagrams for dysphagia (image 2) [1]. Schatzki rings have been identified in up to 13 percent of patients undergoing upper endoscopy for dysphagia [3]. The prevalence of muscular esophageal rings is unclear, however, they appear to be rare and are usually identified in children.

Esophageal webs have been reported in 5 to 15 percent of patients undergoing barium esophagram for dysphagia [2].

PATHOGENESIS — 

The pathogenesis of esophageal webs is unknown. It is hypothesized that esophageal rings are secondary to chronic damage from gastroesophageal reflux. However, a congenital or developmental origin has also been proposed. Evidence for esophageal acid exposure causing esophageal rings is supported by studies showing a reduced risk of recurrence following dilation if treated with acid suppression, as well as a longitudinal radiographic study that demonstrated the evolution of esophageal rings into peptic strictures due to reflux esophagitis [4]. (See 'Acid control to prevent recurrence' below.)

ASSOCIATED CONDITIONS

Esophageal rings — Several conditions have been associated with esophageal rings.

Hiatus hernia — Schatzki rings are almost always associated with a hiatal hernia. In a study of 167 patients with a Schatzki ring, a hiatal hernia was detected in 97 percent [5].

Eosinophilic esophagitis — Schatzki rings have also been associated with eosinophilic esophagitis but this relationship was not confirmed in a systematic review and meta-analysis [6]. Patients with eosinophilic esophagitis typically have multiple esophageal rings, long strictured segments (in extreme cases, narrow caliber esophagus), linear furrows in the mucosa, and eosinophilic abscesses that appear as white papules. (See "Clinical manifestations and diagnosis of eosinophilic esophagitis (EoE)", section on 'Endoscopy'.)

Esophageal webs — Esophageal webs have been associated with Zenker's diverticulum, dermatologic and immunologic disorders, and iron deficiency anemia.

Plummer-Vinson syndrome — The triad of iron deficiency anemia, dysphagia, and a cervical esophageal web is known as Plummer-Vinson or Paterson-Brown-Kelly syndrome (image 3) [7]. Patients with Plummer-Vinson syndrome are typically White females in their fourth to seventh decade of life, but it has also been described in children and adolescents. While in the past Plummer-Vinson syndrome was common in White individuals in northern countries, it is now extremely rare, possibly due to a decreased prevalence of iron deficiency anemia in these countries over time. Recognition of Plummer-Vinson syndrome is important because it is a risk factor for developing esophageal or pharyngeal squamous cell carcinoma.

Other findings that may be present in patients with Plummer-Vinson syndrome include glossitis (picture 1), angular cheilitis, koilonychia (picture 2), splenomegaly, an enlarged thyroid, and symptoms of iron deficiency anemia (eg, fatigue and weakness). It is diagnosed based on the finding of iron deficiency anemia on laboratory testing and by demonstration of an esophageal web on barium esophagram, videofluoroscopy, or upper endoscopy. (See 'Clinical presentation' below.)

In patients with Plummer-Vinson syndrome, iron repletion may lead to rapid resolution of the dysphagia, even before hematologic abnormalities are corrected. However, in patients with significant obstruction of the esophageal lumen, esophageal dilation may be required. Annual surveillance upper endoscopy for esophageal squamous cell carcinoma has also been suggested by some experts, although this has not been shown to improve patient outcomes. (See 'Esophageal webs' above.)

Other associated conditions

●Zenker's diverticulum – Esophageal webs have been associated with Zenker's diverticulum. However, Zenker’s diverticulum is thought to form not as a result of an esophageal web but from a combination of pharyngeal wall weakness at Killian’s dehiscence and fibrostenosis of the cricopharyngeus muscle just distal to that. (See "Zenker's diverticulum".)

●Dermatologic diseases – Esophageal webs can be seen as extracutaneous manifestation of the following dermatologic conditions (table 1):

•Epidermolysis bullosa – Esophageal webs occur in up to 14 percent of cases [8]. (See "Diagnosis of epidermolysis bullosa".)

•Bullous pemphigoid – Esophageal webs can occur in patients with mucous membrane involvement, which accounts for approximately one-third of patients with bullous pemphigoid. (See "Clinical features and diagnosis of bullous pemphigoid and mucous membrane pemphigoid".)

•Pemphigus vulgaris – Esophageal webs can occur in association with oral mucosal lesions. (See "Pathogenesis, clinical manifestations, and diagnosis of pemphigus".)

●Immunologic disorders – In patients with chronic graft-versus-host disease following bone marrow transplantation, esophageal webs can result from the accretions of desquamative esophagitis. (See "Clinical manifestations and diagnosis of chronic graft-versus-host disease".)

CLINICAL PRESENTATION — 

Most esophageal rings and webs are asymptomatic. Symptomatic patients usually present with dysphagia to solids that is particularly evident with hard solids (eg, meat or bread). The dysphagia is often intermittent, and patients will occasionally report modifying how they eat (eg, chewing food more thoroughly). The presence and severity of symptoms depends on the internal diameter of the esophageal lumen. Patients with an esophageal lumen less than 13 mm (39 French) will usually experience solid food dysphagia [1]. However, esophageal rings with an internal 13 to 20 mm diameter can produce dysphagia, particularly when associated with a sliding hiatus hernia. (See "Approach to the evaluation of dysphagia in adults" and 'Hiatus hernia' above.)

Occasionally, patients present with an acute onset of dysphagia or complete inability to swallow saliva due to food impaction. In rare cases, patients with esophageal webs have Plummer-Vinson syndrome and associated clinical features of iron deficiency anemia. (See "Ingested foreign bodies and food impactions in adults", section on 'Clinical manifestations' and 'Plummer-Vinson syndrome' above.)

DIAGNOSIS — 

Esophageal rings and webs are usually diagnosed by barium swallow and/or upper endoscopy for evaluation of dysphagia or other upper gastrointestinal symptoms. In all patients with an esophageal ring, we perform an upper endoscopy to biopsy the esophagus and evaluate for associated eosinophilic esophagitis. (See "Clinical manifestations and diagnosis of eosinophilic esophagitis (EoE)", section on 'Endoscopy' and "Clinical manifestations and diagnosis of eosinophilic esophagitis (EoE)", section on 'Histology' and "Treatment of eosinophilic esophagitis (EoE)", section on 'Esophageal dilation'.)

Barium esophagram — On barium esophagram, a lower esophageal mucosal ring appears as a thin (<3 mm) transverse circumferential ridge a few centimeters above the hiatus of the diaphragm (image 2). Mucosal rings are smooth, symmetric narrowings that are 3 to 5 millimeters in axial extent with a luminal aperture that varies during the course of fluoroscopic examination. However, if the esophagus is not adequately distended, esophageal rings and webs give the appearance of subtle narrowing of the esophageal lumen and can easily be missed.

To adequately distend the esophagus, a barium esophagram should be performed using a full-column technique with the patient performing a Valsalva maneuver after swallowing a solid food bolus while in a prone (or prone oblique) position. The use of a barium tablet (12.8 mm) or marshmallow bolus can help determine if the esophageal ring is the cause of dysphagia if it reproduces the symptoms [9]. A properly performed examination will detect up to 100 percent of esophageal rings compared with detection rates of only 17 to 49 percent for upright double-contrast and mucosal relief techniques [10].

Endoscopy and biopsy — On upper endoscopy, an esophageal web appears as a smooth, thin membrane that is noncircumferential. Endoscopically, an esophageal ring appears as a thin membrane with a concentric smooth contour that projects into the lumen (picture 3). In the case of a Schatzki ring, an associated hiatal hernia is almost always present. Patients may have features of eosinophilic esophagitis (eg, multiple circular rings, linear furrows, whitish papules, and small caliber esophagus). (See "Clinical manifestations and diagnosis of eosinophilic esophagitis (EoE)", section on 'Endoscopy' and 'Associated conditions' above.)

Endoscopy is less sensitive as compared with a barium esophagram for the detection of esophageal rings and webs. Esophageal webs are often missed on upper endoscopy because of their proximity to the upper esophageal sphincter and the inability to adequately distend this region. The lower esophagus must be widely distended to identify an esophageal ring [11]. Applying abdominal pressure can help visualize a Schatzki ring obscured in a reduced hiatal hernia [12]. (See 'Hiatus hernia' above.)

On histology, esophageal rings are composed of mucosa and submucosa with basal cell hyperplasia, hyperkeratosis and, frequently, eosinophilic infiltration [13]. The presence of a large number of eosinophils (>15 eosinophils per high power field) is suggestive of eosinophilic esophagitis. (See "Clinical manifestations and diagnosis of eosinophilic esophagitis (EoE)", section on 'Histology'.)

DIFFERENTIAL DIAGNOSIS — 

The differential diagnosis of an esophageal web or ring is broad and includes other causes of dysphagia. These can be differentiated by history, barium esophagram, and upper endoscopy. (See "Approach to the evaluation of dysphagia in adults", section on 'Symptom-based differential diagnosis'.)

●Achalasia – Patients with achalasia typically present with dysphagia to both solids and liquids and, unlike esophageal webs/rings, symptoms are not intermittent. Findings on barium swallow suggestive of achalasia include dilatation of the esophagus, narrow esophagogastric junction with "bird-beak" appearance, aperistalsis, and delayed emptying (or outright retention) of barium. Upper endoscopy may reveal a dilated esophagus that contains residual food and fluid. The lower esophageal sphincter does not open spontaneously to allow effortless passage of the endoscope but can usually be traversed easily with gentle pressure on the endoscope. (See "Achalasia: Pathogenesis, clinical manifestations, and diagnosis", section on 'Barium esophagram'.)

●Esophageal stricture – Esophageal strictures are longer in axial length as compared with esophageal rings and webs and have tapered ends. The caliber of an esophageal stricture does not change with peristalsis in contrast to a muscular esophageal ring. (See "Endoscopic interventions for nonmalignant esophageal strictures in adults".)

MANAGEMENT

Esophageal webs — Esophageal webs usually rupture during diagnostic upper endoscopy as the endoscope traverses the web. If this does not occur and the web is symptomatic (dysphagia, nasopharyngeal reflux, or aspiration), we perform esophageal dilation.

The approach to dilation is discussed in detail elsewhere. Successful bougie and balloon dilation of esophageal webs have been reported. (See "Endoscopic interventions for nonmalignant esophageal strictures in adults", section on 'Procedure'.)

Esophageal webs do not recur once disrupted and are rarely refractory to esophageal dilation. Incisional therapy can be used for refractory webs.

Esophageal rings

Asymptomatic — Esophageal rings that are asymptomatic (incidentally found) do not require treatment [14].

Symptomatic — The goals of therapy for symptomatic esophageal rings are relief of dysphagia and prevention of recurrent symptoms.

Initial endoscopic treatment — Primary therapy of symptomatic esophageal rings is endoscopic dilation (picture 4 and picture 5). We generally perform this at the time of initial endoscopy in patients who have no features of eosinophilic esophagitis (eg, multiple stacked circular rings, linear furrows, whitish papules, and small caliber esophagus). If there is concern for eosinophilic esophagitis, we await results of biopsy prior to proceeding to dilation, although immediate dilation is reasonable when there is a high-grade or symptomatic obstruction. (See 'Patients with eosinophilic esophagitis' below.)

In general, we perform graded dilation, as for esophageal stricture, with progressively larger dilators until the ring is disrupted, in accordance with guidelines from the British Society of Gastroenterology. This slightly differs from the recommendation of the American Society for Gastrointestinal Endoscopy that suggests a graded dilation only if it is uncertain whether the lesion is a Schatzki ring or peptic stricture [15].

Graded dilation is generally thought to be associated with a lower risk of perforation than single dilation, although the risk of perforation is low with both for patients with Schatzki ring. A single dilation with a large bougie dilator (≥50 French) or balloon dilator (18 to 20 mm) is still often performed and successful in alleviating dysphagia in most patients with a low risk of complications [16-18]. However, it has not been shown to be more effective than graded dilation [19].

The technique for esophageal dilation is discussed in detail elsewhere. (See "Endoscopic interventions for nonmalignant esophageal strictures in adults", section on 'Procedure'.)

Acid control to prevent recurrence — Following esophageal dilation, we treat patients with an esophageal ring with a once-daily standard dose of a proton pump inhibitor (PPI; eg, omeprazole 20 mg daily or equivalent). We generally suggest that patients continue the PPI indefinitely but discuss risks and benefits with the patient. Adverse effects of long-term PPI use are discussed elsewhere. (See "Proton pump inhibitors: Overview of use and adverse effects in the treatment of acid related disorders", section on 'Adverse effects'.)

Some patients with esophageal rings have severe underlying gastroesophageal reflux (eg, erosive esophagitis), and indefinite PPI use is important for esophageal healing and preventing symptom recurrence and complications. (See "Initial management of gastroesophageal reflux disease in adults", section on 'Patients who respond to initial treatment'.)

Otherwise, long-term acid suppression may reduce the risk of esophageal ring recurrence, even in patients without reflux symptoms or evidence of gastroesophageal reflux disease (GERD) on pH testing, although data are limited. In a randomized trial with 44 consecutive patients who underwent dilation of a Schatzki ring, all patients with objective evidence of GERD on esophageal 24-hour pH testing were treated with omeprazole [20]. The remaining patients were randomly assigned to omeprazole or placebo. There were no recurrences of Schatzki rings in patients with GERD during a mean follow-up of 43 months. Among the patients without GERD, the probability of recurrence was lower in patients assigned to omeprazole as compared with placebo (recurrence rates 8 percent [1 of 13] versus 58 percent [7 of 12] after a mean follow-up of 20 months). However, given the limitations of a 24-hour pH test in detecting GERD, some patients in the non-GERD group may have been misclassified.

Management of recurrent rings — We treat recurrent symptomatic esophageal rings with repeat dilation and long-term acid suppression. In patients with frequent recurrences (eg, more than one or two times per year) we also obtain additional mucosal biopsies of the esophagus to rule out eosinophilic esophagitis as eosinophilic infiltration can be intermittent and/or patchy.

Recurrent dysphagia occurs in a majority of patients with esophageal rings after an initial response to esophageal dilation [17,20-22]. In a study that evaluated 33 patients after dilation of an esophageal ring to ≥50 French, recurrent dysphagia one, two, and five years post-dilation were reported in 32, 65, and 89 percent of patients, respectively [17]. Neither the initial ring size nor the presence or absence of esophagitis correlated with symptomatic recurrence.

Management of refractory rings — A small subset of patients with esophageal rings have refractory symptoms that do not improve despite repeated attempts at esophageal dilation. For such patients, we obtain additional mucosal biopsies of the esophagus to rule out eosinophilic esophagitis. For refractory rings in patients who do not have eosinophilic esophagitis, we use an alternative technique to disrupt the esophageal ring [21,23].

The choice of therapy depends on the prior technique used for dilation and the endoscopist's familiarity with the treatment options. Therapeutic endoscopic options include:

●Balloon or bougie dilation – Balloon dilation can be used if the initial treatment was with bougienage and vice versa.

●Biopsy obliteration – Feasibility of using biopsy forceps to rupture a Schatzki ring with 4-quadrant biopsies or obliterate it with multiple biopsies has been described in a small number of patients [23,24].

●Incisional therapy – Endoscopic incisional therapy using electrocautery to create radial incisions around the ring can be used to dilate a refractory esophageal ring (picture 6). In a randomized trial, electrosurgical incision offered somewhat better improvement in dysphagia at one-month and a modestly longer symptom-free period compared with bougie dilation (eight versus six months) [21]. Case series also suggest that electrosurgical incision can be effective in patients with refractory esophageal rings [25], although a higher complication rate than standard dilation has been reported in children [26]

Other proposed interventions with limited or no supportive clinical evidence include laser division and injection of corticosteroids prior to dilation.  

Patients with eosinophilic esophagitis — The approach to esophageal rings and other strictures in patients with eosinophilic esophagitis is discussed in detail elsewhere. (See "Treatment of eosinophilic esophagitis (EoE)", section on 'Esophageal dilation'.)

SOCIETY GUIDELINE LINKS — 

Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Esophageal strictures, foreign bodies, and caustic injury".)

SUMMARY AND RECOMMENDATIONS

●Terminology – Esophageal rings and webs are thin structures that partially occlude the esophageal lumen.

•Esophageal ring – This refers to a concentric (2 to 5 mm) diaphragm of tissue that protrudes into the esophageal lumen. They are typically located in the distal esophagus but can occur in other parts. Schatzki ring, a narrow mucosal ring typically associated with hiatal hernia, is the most common type. (See 'Anatomy' above and 'Terminology' above.)

•Esophageal web – This is a thin (<2 mm) eccentric membrane that protrudes into the esophageal lumen. Esophageal webs are covered with squamous epithelium and most commonly occur anteriorly in the cervical esophagus, causing focal narrowing in the postcricoid area (image 1). (See 'Terminology' above.)

●Clinical features – Most esophageal rings and webs are asymptomatic. Symptomatic patients usually present with intermittent dysphagia to solids. The presence and severity of symptoms depends on the internal diameter of the esophageal lumen. Patients with an esophageal lumen less than 13 mm (39 French) will usually experience solid food dysphagia. Occasionally, patients present with acute dysphagia and/or complete inability to swallow saliva due to food impaction. (See 'Clinical presentation' above.)

●Diagnosis – Esophageal rings and webs are usually diagnosed by barium swallow and/or upper endoscopy for evaluation of dysphagia or other upper gastrointestinal symptoms. In all patients with an esophageal ring, we perform an upper endoscopy to biopsy the esophagus and evaluate for associated eosinophilic esophagitis. (See 'Diagnosis' above.)

●Management

•Esophageal webs – These are usually ruptured during diagnostic endoscopy by passage of the endoscope through the web. However, in symptomatic patients with a partial disruption of an esophageal web, we perform esophageal dilation.

•Esophageal rings – Asymptomatic rings do not require intervention. For patients with a symptomatic esophageal ring without associated eosinophilic esophagitis, we suggest graded dilation with either balloon or wire-guided bougie dilators rather than single, large caliber dilation (Grade 2C). Graded dilation is the usual approach for esophageal dilation in general, and there is no evidence that single large-caliber dilation is more effective. (See 'Asymptomatic' above and 'Initial endoscopic treatment' above.)

Some patients may have severe underlying gastroesophageal reflux (eg, erosive esophagitis) that requires lifelong acid suppression. For patients with symptomatic esophageal rings who would not otherwise have an indication, we suggest indefinite proton pump inhibitor (PPI) therapy rather than short-term or no PPI treatment following dilation (Grade 2C). Long-term acid suppression may reduce the risk of recurrence. (See 'Acid control to prevent recurrence' above.)

In patients with frequent recurrences (eg, more than one or two times per year) or refractory symptoms, we obtain additional biopsies of the esophagus to rule out eosinophilic esophagitis. We treat recurrent symptomatic esophageal rings with repeat dilation. For refractory rings in patients who do not have eosinophilic esophagitis, we use an alternative technique to disrupt the esophageal ring. (See 'Management of recurrent rings' above and 'Management of refractory rings' above.)

Management of esophageal rings in the context of eosinophilic esophagitis is discussed in detail elsewhere. (See "Treatment of eosinophilic esophagitis (EoE)", section on 'Esophageal dilation'.)