Imaging description

Epiphrenic diverticula are outpouchings of the distal esophagus just above the diaphragm that appear as thin-walled, air or air-fluid filled structures adjacent to the distal esophagus. An epiphrenic diverticulum can mimic a hiatal hernia at CT (Figures 6.1 and 6.2) [1].

Importance

Misdiagnosis of an epiphrenic diverticulum as a hiatal hernia is unlikely to have serious consequences, but might result in a missed opportunity to recognize a treatable esophageal disorder. Occasionally, epiphrenic diverticula can be complicated by malignancy, obstruction, bleeding, or perforation and are then of greater clinical importance [2–6]. An epiphrenic diverticulum has been described as a cause of false positive uptake at iodine-131 scintigraphy, potentially resulting in a misdiagnosis of metastatic thyroid cancer [7].

Typical clinical scenario

Epiphrenic diverticula are believed to be pulsion diverticula generated by underlying esophageal dysmotility [8], although not all patients complain of dysphagia or have dysmotility evident on esophagography [9]. While most patients can be treated conservatively, some may require surgery. Operative correction requires both a diverticulectomy and a myotomy to address the underlying motility disorder [8].

Differential diagnosis

The primary differential is a hiatal hernia, which is a far commoner abnormality of the distal esophagus. A diverticular neck is rarely seen at CT in cases of epiphrenic diverticula. Two other observations are more helpful in the distinction of epiphrenic diverticula from hiatal hernias (Figures 6.3 and 6.4):

• Epiphrenic diverticula are thin-walled while hiatal hernias are thick-walled and contain gastric mucosa and rugae.

• Hiatal hernias are usually associated with widening of the esophageal hiatus, which has been defined as “whenever the diaphragmatic crura were not tightly opposed and in intimate association with the esophageal wall” [10].