Spontaneous onset and resolution of gastroesophageal intussusception during contrast-enhanced computed tomography.

Background: Gastroesophageal intussusception is a rare condition in dogs, most commonly presenting as an acute, life-threatening disease. In some dogs with chronic disease, intermittent intussusception is suspected to underlie clinical signs, although its relationship with other oesophageal disorders remains poorly understood. Transient intussusception has only been reported in one endoscopic study, where concurrent assessment of the oesophageal hiatus was not possible. To the best of the authors' knowledge, spontaneous reduction has never been definitively demonstrated tomographically. Case Description: A 10-year-old neutered male Australian Terrier presented to his local veterinarian after an episode of retching and collapse. He was referred to an internal medicine specialist and underwent computed tomography to look for possible underlying causes, as well as to investigate chronic, pre-existing respiratory disease. The gastric cardia and gastroesophageal junction herniated into the caudal thorax after contrast administration, before returning to a normal position on subsequent acquisitions, consistent with a sliding hiatal hernia. The patient was discharged for medical management and presented to a different referral hospital the following year for the evaluation of a sublumbar mass identified on abdominal ultrasound. Computed tomography revealed a mass arising from the right iliopsoas muscle, and a cytological diagnosis of hemangiosarcoma was made. The stomach was in its normal position on pre-contrast and delayed post-contrast images. However, on venous-phase images acquired between these time points, the gastric fundus was cranially herniated through the oesophageal hiatus into the caudal oesophageal lumen, with the gastroesophageal junction remaining appropriately positioned. These findings were consistent with self-resolving gastroesophageal intussusception. No treatment was pursued for the intussusception, and treatment for haemangiosarcoma was declined. A poor prognosis was given, and the patient died 5 days later without a postmortem examination. Conclusion: This is the first reported case of gastroesophageal intussusception in a dog that was tomographically determined to be self-resolving and the first case of gastroesophageal intussusception in association with an untreated hiatal hernia.