For gastrointestinal endoscopists and otolaryngologists, esophageal intrudus is the arbitrary yet overlapping boundary. In this review, we cover the lower part of the hypopharynx, posterior to the larynx, the opening posterior to the cricoid prominence, and the cervical esophagus. We demonstrate their anatomy, endoscopic findings and pathologies, and their management. The esophageal intrudus, or upper esophageal sphincter muscles, include the inferior pharyngeal constrictor, cricopharyngeus, and cervical esophageal muscle. The length of the upper sphincter muscle is about 3-5 cm, and the cricopharyngeus is the main component of these closure muscles. The cricopharyngeus muscle locates at the level of esophageal opening. Endoscopic examination of the esophageal intrudus starts from the oropharynx. At the inlet of the oropharynx, soft palate, uvula, bilateral palatine tonsil, and valid papillae and lingual follicles of the posterior tongue can be observed. This is the epiglottis in the midline. The space behind the epiglottis is called the vollicular. At the hypopharyngeal inlet, the endoscopist should visualize the following landmarks. Airy epiglottic fold, cuneiform tubercle, coniculate tubercle, inter-arytenoid notch, laryngeal inlet and vocal cords, epiglottis, and vollicular behind the epiglottis. This is the laryngeal inlet and the vocal cords. The piriform fossa can be found on each side of the larynx. Normal hypopharyngeal and esophageal mucosa should appear whitish pink or silver red in color, smooth and with fine vascular patterns. Digital chromoendoscopy, such as narrowband imaging, can be used to highlight mucosal vascular pattern and certain endoscopic findings and lesions. The normal mucosal lining within the intrudus is squamous. We should not see much mucosal accumulation within the hypopharynx. With gentle pressure, the endoscope is advanced through the esophageal opening into the cervical esophagus. The esophageal opening is located between the bilateral piriform fossae and posterior to the cricoid cartilage. The cricopharyngeal muscle locates at the level of esophageal opening, which is usually located at 14-15 cm measured from the incisor teeth, posteriorly at about the level of C6 vertebra. In addition to white light endoscopy, we also use digital chromoendoscopy to examine the esophageal opening and the cervical esophagus. Examination of the hypopharynx can be limited if an endotracheal tube is in place. Occasionally, we can find benign findings such as glycogenic acanthosis. They appear as focal or multifocal whitish smooth plaques of a few mm in size, and they are hyperplastic squamous epithelium with abundant intracellular glycogen deposits. Clinically, mild glycogenic acanthosis is a normal finding and does not progress to esophageal cancer or stricture. Extensive glycogenic acanthosis has been shown to be associated with Cowden's syndrome. This patient had total esophagectomy with colonic interposition. Some vascular ectasia can be seen within the larynx. Cologastric anastomosis can be seen at the level of the diaphragm. The proximal surgical anastomosis can be seen just below the esophageal opening. This patient had esophagectomy with gastric pull-up. Patients with gastric pull-up are prone to develop acid reflux and aspiration. This is the larynx and the vocal cords. After difficult or traumatic esophageal intubation, sometimes we can observe submucosal hematoma, dissection, or submucosal error or bleb. In addition, we can cause iatrogenic mucosal tear or perforation within the esophageal intrudus. The prevalence of gastric mucosal heterotopia in the cervical esophagus is about 2%. The salmon-colored patch is often called inlet patch. Gastric mucosal heterotopia is best observed under digital chromoendoscopy. The inlet patch can be singular or multiple. Infrequently, circumferential gastric heterotopia or inlet segment can be found. Endoscopic biopsy is needed to confirm the diagnosis and to rule out other pathology. Occasionally, helicobacter pylori infection can be present in the inlet patch. In symptomatic inlet patch or segment, the patient often complain of retrosternal burning sensation, dysphagia or dynophagia, throat irritation, hoarseness, and coughing. Infrequently, gastric mucosal heterotopia can cause esophageal stretchers and webs. This patient presented with food boulders impaction within the esophageal intrudus. After endoscopic disimpaction, inlet segment with esophageal stretcher can be seen. Fortunately, malignant transformation to cervical esophageal adenocarcinoma is extremely rare. Inlet patch or segment should not be considered as a precancerous condition. Asymptomatic inlet patch requires neither specific therapy nor endoscopic surveillance. Management of symptomatic lesion can start with proton pump inhibitor. If optimal symptomatic control cannot be achieved, endoscopic ablation with bipolar coagulation, argon plasma coagulation, or radiofrequency device can be attempted. An esophageal ring is usually defined as a concentric, smooth, and thin constriction within the esophagus. Ringed esophagus, corrugated esophagus, and feline esophagus has been used to describe esophagus with multiple rings. The proposed etiologies for the development of esophageal rings or webs include congenital malformation, iron deficiency, inflammation, and autoimmunity. A moderate to severe ring is seen within the esophageal intrudus. After dilatation, multiple rings can be seen in the cervical esophagus with mucosal erythema and luminal narrowing. Biopsied specimen showed nonspecific esophagitis without eosinophilic infiltrates. This patient has biopsy-proven eosinophilic esophagitis. Multiple esophageal rings and linear furrows can be seen throughout the entire esophagus. This is another patient with eosinophilic esophagitis. Besides the linear furrows, we can see numerous eosinophilic microabscesses appear as whitish dots. This patient has iron deficiency anemia and esophageal webs. The esophageal webs are usually limited to the cervical esophagus. Compared to the esophageal rings, the esophageal webs are considered to be more eccentric than concentric in morphology. Symptomatic esophageal rings or webs can be managed by endoscopic dilatation. Sometimes, Plummer-Vinson syndrome refers to patients with symptomatic esophageal webs and iron deficiency anemia. Besides dilating the dominant rings or webs, the treatment should focus on correcting the iron deficiency anemia and controlling the underlying inflammation. A cricopharyngeal bar is a radiologic description of a posterior impression within the esophageal intrudus. The cricopharyngeal bar is a common and incidental radiologic finding. In many cases, it does not cause symptoms. If patient has pharyngeal esophageal dysphagia and is sought to do the cricopharyngeal bar, this condition has also been termed cricopharyngeal akalasia. Cricopharyngeal akalasia is suspected in this patient. The diagnostic gastroscope could not be advanced through the esophageal opening into the cervical esophagus. A ultrasound gastroscope is being used to pass the esophageal opening and to route distal obstruction. This patient had a normal CT scan of the neck to route an extrinsic lesion. Under endoscopic guidance, an esophageal manometry probe is placed into the esophagus and cross the esophageal intrudus in order to measure the upper esophageal sphincter pressure and esophageal peristalsis. During subsequent endoscopy, savory dilatation of the esophageal intrudus and cricopharyngeal bar is performed. Patient enjoyed optimal and long-term symptomatic relief. Because the true incidence of symptomatic Quaker pharyngeal bar is low, the endoscopist need to rule out other pathology within the esophageal intrudus. In this patient with dysphagia, bilaterally enlarged tonsils are the culprits. The treatment options for cricopharyngeal spasm include endoscopic dilatation, endoscopic botox injection, and cricopharyngeal myotomy. After head and neck or chest radiation, post-radiation stenosis usually develops at the esophageal opening or within the cervical or mid-esophagus. Chronic radiation mucosal changes can usually be observed, such as loss of vascular pattern, patchy erythema, angioictasia, and scar formation. Most benign esophageal structures are amenable to endoscopic dilatation. Endoscopic dilatation can be achieved using through-the-scope endoscopic balloon dilator or over-the-wire savory dilator. In this case, the balloon is inflated to 15 mm. Post-dilatation endoscopic examination reveals small mucosal tears within the cervical esophagus and esophageal opening. Chronic radiation mucosal changes can be seen in the pharynx and the larynx. If the stricture is moderate to severe within the esophageal intrudus, it is safer to perform endoscopic dilatation under fluoroscopic guidance. In cases of high-grade or complex stricture, wire-guided balloon dilator and contrast injection are likely to improve the safety margin of endotherapy. This patient had esophagectomy with gastric pull-up. A mild anastomotic stricture is seen within the esophageal intrudus with surgical staples and sutures. In this patient, a moderate to severe anastomotic stricture is located within the intrudus. Under fluoroscopic guidance, wire-guided balloon dilatation is performed. Occasionally, a tracheoesophageal puncture prosthesis can be seen in the cervical esophagus. Other intrinsic etiology of strictures are covered in other chapters in this review. In this patient, the extrinsic compression within the cervical esophagus is due to surrounding lymphadenopathy related to sarcoidosis. The differential diagnosis is submucosal cyst or neoplasm. In this patient, a mass lesion in the medial sinum is causing extrinsic compression in the cervical esophagus. In this patient with dysphagia, significant extrinsic compression can be found within the esophageal intrudus. The culprits are the osteophytes related to cervical vertebrae. The luminal patency within the intrudus has significantly improved after surgery. Several months after surgery, endoscopy revealed erosion within the cervical esophagus, likely from residual osteophytes. Foreign body impaction within the esophageal intrudus is a serious condition. If the foreign body is suspected in the hypopharynx, otolaryngologist is often called by the emergency room. Gia endoscopist is often called if the foreign body cannot be located within the hypopharynx or is suspected in the esophagus from the beginning. A wishbone, a Y-shaped bone found in birds, is impacted within the esophageal intrudus. If the sharp foreign body has penetrated the mucosa, or optimal endoscopic view cannot be obtained, the endoscopist should refrain from pushing down the foreign body using the endoscope. In this case, the wishbone is removed with the endoscopic grasping device. Endoscopic examination of the intrudus should be performed after foreign body removal. After this patient spontaneously passed an impacted foreign body, a small perforation developed. On neck CT, a small amount of air can be seen around the esophageal intrudus. The patient was managed conservatively with antibiotic. After recovery, an elective endoscopy showed a healing perforation site with surrounding tissue edema. In this patient, a dental prosthesis is impacted within the esophageal intrudus. During endoscopy, the area epiglottic fold is edematous on one side. The impacted denture is seen within the esophageal opening. We use an endoscopic grasping device to capture the impacted denture. With a slow and gentle pulling force and fine twisting of the endoscope, the impacted denture is removed uneventfully. Endoscopic inspection of the cervical esophagus and intuitus reveals several ischemic alterations from the impacted denture. Occasionally, we can encounter meat boulders impaction within the intrudus or cervical esophagus due to underlying stricture, rings, or web. In these cases, the proximal portion of the food boulders can be removed with an endoscopic foreign body grasping device or endoscopic net retriever. In every case, proper airway protection should be considered and practiced if the foreign body is removed preorally. After partial meat boulders disimpaction or removal, the residual boulders can be pushed down safely into the stomach. In this case, the underlying mucosal pathology is circumferential gastric mucosal heterotopia or inlet segment with a mild stricture. Three types of diverticulum can be found within the esophageal intrudus and cervical esophagus. The lateral pharyngeal diverticulum, Zanker's diverticulum, and Kilier-Jameson diverticulum. During the evaluation of suspected diverticulum, barium esophagram with anterior, posterior, and lateral views should be obtained. In addition, radiofluoroscopic swallowing study can shed additional light in patients with pharyngeal esophageal dysphagia. The lateral pharyngeal diverticulum is a pulsion-type diverticulum. It is usually situated within the piriform fossa. Most of these diverticulars are unilateral, and their diameter generally ranges from 1 to 2.5 cm. In this patient, the barium esophagram delineates the diverticulum. The associated symptoms can include neck pain, regurgitation, dysphagia, and a globus sensation. The Zanker's diverticulum is the protrusion of the pharyngeal mucosa through the cricopharyngeal muscle. Within or slightly below the esophageal intrudus, we should visualize a prominent cricopharyngeal bar or septum associated with Zanker's diverticulum. Due to the presence of the cricopharyngeal bar and diverticulum, esophageal intubation by the endoscope or nasogastric tube can be difficult. On barium esophagram, unlike the lateral pharyngeal diverticulum, the Zanker's diverticulum protrudes posteriorly. Bilateral Zanker's diverticulum is very infrequent. Post-traumatic diverticulum can mimic Zanker's diverticulum. Barium accumulation within the diverticulum and aspiration can clearly be visualized in this video fluoroscopic swallow study. For symptomatic Zanker's diverticulum, traditional surgery involves transcervical diverticulectomy and cricopharyngeal myotomy. More otolaryngologists have adopted the rigid endoscopic stapler-assisted diverticulotomy, in short, ESD. With a flexible endoscope, expert endoscopists approach the Zanker's diverticulum by dissecting the cricopharyngeal bar and septum using a variety of thudoscope coagulation or cutting devices. The treatment goal is to release the cricopharyngeal spasm by performing diverticulotomy. In addition, some endoscopists routinely place 1-3 endoclips at the bottom of the dissected septum. Killian-Jameson diverticulum protrudes through the anterior lateral wall of the cervical esophagus, inferior to the cricopharyngeal muscle. Unlike the Zenker's diverticulum, Killian-Jameson diverticulum does not have a cricopharyngeal bar or septum. The diverticulum arises inferior and lateral to the Zenker's diverticulum. Due to the rich vascular supply, hypopharyngeal and esophageal ischemia, or necrosis, is not common. Acute esophageal necrosis, also called black esophagus, can develop in patients with vascular disorder, systemic no-flow state, with acute hemodynamic instability. Probably due to the additional insult from acid regurgitation. The ischemic findings in the black esophagus are most pronounced in the distal to mid-esophagus. The most common presenting symptoms is acute upper gl bleeding. The treatment is supportive care with aggressive acid reduction therapy. The diffuse dark pigmentation of the esophagus, in this case, is not from ischemia, but rather from semicosal hemorrhage due to coagulopathy and thrombocytopenia. In this patient, there is no portal hypertensive gastropathy, and the distal esophagus appears normal. However, proximal esophageal varices, often called downhill varices, are noted in the cervical esophagus. Downhill varices can be found in patients with superior vena cava syndrome. The normal blood flow direction is reversed in the upper esophageal plexus. The reported etiology of superior vena cava obstruction includes lung or thyroid carcinoma, chronic mediastinal fibrosis, surgical ligation of the superior vena cava or metastatic mass to the mediastinum. Bleeding from the downhill varices is rare. Endoscopic band ligation or injection sclerotherapy have been reported for proximal variceal bleeding. In this patient, small downhill varices can be seen within the esophageal intrudus. Within the hypopharynx and esophageal intrudus, a variety of etiologies and pathogens can cause mucositis and infections. In laryngopharyngitis, the mucosa appears edematous, inflamed, and with a loss of vascular pattern. The etiology of pharyngitis can either be primary or secondary to esophageal reflux or vomiting. The pharyngeal esophageal swallowing function is impaired in this patient after suffering a stroke. This mucositis develops as a consequence of impaired clearance of oral mucosal secretion. In esophageal reflux disease, most of the mucosal injury can be seen in the distal to midi-esophagus. In severe reflux disease, or if patient has recurrent vomiting, the esophageal intrudus and hypopharynx can be involved. Esophagitis desiccans superficialis is characterized by sloughing of large fragments of the esophageal squamous mucosa. It is a benign and temporary endoscopic finding without clear etiology. In acute radiation mucositis, we can observe mucosal edema, erythema, loss of vascular pattern, peeling of the mucosa, friability, or even ulceration. In chronic radiation mucositis, endoscopic findings include mucosal edema, patchy erythema with loss of vascular pattern, scarring, and angiocasia. Certain medications can induce direct mucosal injuries within the intrudus and esophagus. They include non-steroidal anti-inflammatory drugs, iron supplements, doxycycline, alendronate, and others. Esophageal intrudus, aortic indentation within the mid-esophagus, and distal esophagus are three common locations that are prone to develop drug-induced mucositis. At these locations, we can observe solitary, patchy, or circumferential mucositis, erosions, or ulcerations. Caustic or corrosive ingestion can induce extensive mucositis and potential necrosis within the pharynx, esophagus and stomach. In this patient, diffuse mucosal injury is seen within the hypopharynx, the entire esophagus and at the dependent portion of the stomach. Pymphagus is a rare autoimmune disease which patient develop blistering lesion involving the skin and mucous membrane. In this patient with Pymphagus, blistering lesions can be found within the pharynx, esophageal intrudus and cervical esophagus. She has significant throat symptoms or dynophagia and dysphagia. The distal and mid esophagus is spared. Peeled mucous membrane from the blistering lesion is seen in the cervical esophagus. This patient has Mucous Membrane Pymphagoid, i.e. MMP, also called Psychiatrical Pymphagoid. MMP is a rare autoimmune disease primarily involving the mucous membrane. Blistering lesion and scarring can be found in this condition. Due to scarring, patient can develop esophageal webs or strictures. Despite immunosuppressive therapy, some patients need endoscopic dilatation to treat the symptomatic dominant esophageal strictures. In order to avoid or minimize extensive blister formations after dilatation, we prefer to use through-the-scope endoscopic balloon dilator instead of savory dilator. In MMP, esophageal involvement generally develops in patients with established ocular disease. In established graft-versus-host disease, the endoscopic findings range from normal appearing mucosa to macroscopic mucositis or even ulceration. Oropharyngeal and esophageal candidiasis is a common infection affecting the elderly and immunocompromised patients. In severe cases, the mucosa is covered with whitish curd-like substance. In mild cases, the whitish substance is patchy in distribution. The affected patients can be asymptomatic or present with odynophagia and dysphagia. The artifact from oral spray can mimic pharyngeal and esophageal candidiasis. Acute herpes simplex infection can involve the oropharynx and esophagus. This patient suffers from actinomycosis involving the posterior pharyngeal wall within the hypopharynx. Actinomycosis typically occurs following oral surgery or in patients with poor dental hygiene. Infected area can develop fistula or sinus tracts that discharge purulent materials. Occasionally, idiopathic oropharyngeal and esophageal ulceration can be found in patients with late-stage HIV infection. The ulceration is generally large and the diagnosis is made by exclusion of other ideologies. Endoscopic biopsy of the ulcer margins and base should be performed. In this patient with advanced HIV infection, histoplasmosis involves the cervical esophagus. The diagnosis is made by endoscopic biopsy. Acquired tracheoesophageal fistulas are generally caused by neoplasm, infection, and trauma. This patient has a malignant TE fistula in the cervical esophagus. This patient has HIV infection and resolving tuberculosis. Despite anti-TB treatment, a persistent esophageal fistula is seen in the cervical esophagus. Temporary endoluminal stenting or tissue approximation using endoclips or suturing device can be used to manage these fistulas. In this patient, a fistula opening is seen in the cervical esophagus, and it was caused by iatrogenic injury during tracheostomy. After obtaining multidisciplinary consult and per patient family request, we proceed with endoluminal stenting. A fully covered esophageal stand was placed, with a proximal flange crossed the esophageal intrudus. After cervical esophageal stenting, many patients can develop throat symptoms. Fortunately, this patient tolerated cervical stenting well without any throat symptoms. The fistula opening is completely covered. After a negative contrast swallow study, the patient was started on an oral diet and was discharged home. During upper endoscopy, a small papilloma is seen incidentally on the area epiglottic fold. A small papilloma in the cervical esophagus. In this patient, papillomatosis involved the entire esophagus. For solitary papilloma ablation, endoscopic excisional biopsy or endoscopic mucosal resection can be performed. In the setting of diffuse papillomatosis, regular endoscopic surveillance with biopsy is recommended, since there is an increased risk of malignant transformation. In this patient with squamous carcinoma of the vocal cord, the larynx is asymmetrical and edematous. The esophageal intrudus and cervical esophagus appear normal. In this patient, squamous carcinoma involved the larynx. The bilateral area epiglottic folds are edematous and indurated. The esophageal intrudus is relatively spare in this case. Despite having squamous carcinoma involving the esophageal intrudus, the hypopharyngeal inlet and piriform recess on this side appear to be normal. Only within the postquicoid recess and piriform fossa on the other side, we can see the neoplastic tissue. This case highlights the importance of careful examination of the hypopharynx and esophageal intrudus. The cervical esophagus appears normal under white light endoscopy. Under digital chromoendoscopy, multifocal dysplastic area can be seen. This is another case of squamous carcinoma involving the esophageal intrudus. The vast majority of cancers involving the hypopharynx and esophageal intrudus are squamous carcinomas. It is difficult to diagnose cancer in the hypopharynx and esophageal intrudus at an early stage. The incidence of poorly differentiated cancer is also higher in this region. The endoscopist needs to examine the hypopharynx and esophageal intrudus systematically and carefully. to better delineate squamous dysplasia in the esophagus. We traditionally spray diluted Lugol solution in the esophagus. This endoscopic practice has been largely replaced by applying digital chromoendoscopy. In this patient with squamous carcinoma involving the cervical esophagus, we examine the lesion under white light endoscopy and digital chromo endoscopy. One of the common benign neoplasm involving the esophagus is granular cell tumor. They appear a small submucosal nodule with a whitish hue. For a small and solitary lesion, it can be safely removed with band-assisted endoscopic mucosal resection. The nodule is being suctioned into the band ligation cap. After capturing the optimum amount of tissue in the ligation cap, the rubber band is deployed. The opened endoscopic snare is placed below the deployed rubber band. The snare is then closed. Blended cut or coagulation current is applied. The submucosal nodule is then completely removed. In this patient, a large submucosal lesion is seen within the esophageal intrudus. It also has a whitish hue. Fine needle aspiration of this lesion confirms the diagnosis of granular cell tumor. In this case, the granular cell tumor is multifocal. This is another lesion in the mid-to-distal esophagus. Infrequently, other uncommon neoplasms can be found within the esophageal intrudus and hypopharynx.

esophageal intrudus

endoscopic findings

management

hypopharynx

pathologies

proton pump inhibitors

dilatation

malignancies

endoscopic techniques

visualizing