Teaching Case

A 50-year-old man, who was previously healthy, was discharged by our gastroenterologist with symptoms that included progressive intermittent but severe dysphagia, halitosis, paroxysms of coughing and regurgitation of food and liquids. He also had an unintentional weight loss of 20 kg. These symptoms developed during a 15-month period.

A 50-year-old man, who was previously healthy, was discharged by our gastroenterologist with symptoms that included progressive intermittent but severe dysphagia, halitosis, paroxysms of coughing and regurgitation of food and liquids. He also had an unintentional weight loss of 20 kg. These symptoms developed during a 15-month period. He had no history of tobacco or alcohol use. Results of the physical examination done were found to be normal. A radiographic image was obtained (Fig. 1). A large fluid level was observed from the midline at the upper mediastinum above the aortic arch; there was no evidence of a lower mediastinum widening. Based upon these findings, a barium esophageal examination was recommended. After swallowing barium, there appeared a large esophageal outpouching arising from the midline of the posterior wall of the pharyngoesophageal junction. The radiological diagnosis suggested that the patient had a pharyngoesophageal diverticulum (Zenker´s diverticulum). All the swallowed barium was trapped into the diverticulum without there being a normal transit to the esophagus which was only evident when the diverticulum was full (Fig. 2). The esophagus was displaced anteriorly by the diverticulum which was located between the esophageal-tracheal axis and the spine.

Zenker's diverticulum is a pseudodiverticulum consisting of mucosa and submucosa that arise from the posterior portion of the inferior pharyngeal constrictor muscle. The Zenker diverticulum occurs at an area of potential weakness in the inferior pharyngeal constrictor muscle referred to as the Killian dehiscence. It is located between the obliquely oriented fibers of the thyropharyngeal muscle and the horizontally oriented fibers of the cricopharyngeal muscle. No mechanism of pathogenesis has been generally accepted as yet, although the most recent have studies confirmed that there is an increased intrabolus pressure in patients with Zenker's diverticulum. The most common presenting feature is upper esophageal dysphagia, which occurs in as many as 98% of patients. Other common symptoms include halitosis, regurgitation of undigested food, noisy swallowing, and aspiration. Some patients also report excessive salivation and the sensation of a mass within the throat. Weight loss and recurrent pulmonary infections occur in approximately one-third of the patients. Patients with minimal symptomatology who do not desire surgical therapy may be followed up on a routine outpatient basis by monitoring their symptoms. Weight loss, progression of dysphagia, aspiration, recurrent pulmonary infections, and bleeding should prompt a consideration of surgical therapy. Fluoroscopic barium esophagography is the mainstay of the diagnosis of the Zenker diverticulum. Physical examination findings are rare, although some extremely large diverticula are occasionally palpable on examination. These are usually present to the left of the midline. The Zenker diverticulum may be found on endoscopy; however, fluoroscopy remains the diagnostic study of choice. Care must be taken while performing an endoscopy in patients with a known history of Zenker's diverticulum, as the passage of the endoscope into the diverticulum carries some risk of perforation. Fluoroscopic barium esophagraphy is the primary tool used for the diagnosis of Zenker's diverticulum. The diverticulum appears as an outpouching arising from the midline of the posterior wall of the distal pharynx near the pharyngoesophageal junction. This is best identified during swallowing and is best seen on lateral view images, on which the diverticulum is typically noted at the C5-6 level. When the diverticulum is large enough to protrude laterally, it protrudes to the left in 90% of the cases. After the contrast agent bolus passes the upper esophagus, the diverticulum is typically seen extending posterior to the cricopharyngeus muscle, and the contrast material that was trapped within the diverticulum may be regurgitated back into the hypopharynx. Occasionally, a patient may aspirate contrast material from the diverticulum. The lumen of the diverticulum must be carefully observed for irregularities or filling defects within the diverticulum which may indicate the rare complication of squamous cell carcinoma. When incidentally imaged on CT or MR scans, Zenker's diverticulum appears as a structure arising posteriorly from the hypopharynx and is filled with gas, fluid, oral contrast material, or a mixture of these. Several surgical options exist; however, the approach most frequently cited is myotomy of the cricopharyngeus muscle with or without diverticulopexy. Endoscopic treatment of Zenker's diverticulum, including endoscopic stapling, holds promise and is currently being investigated in clinical trials.