Imaging description

Gastric diverticula are rare, with an approximate incidence of one in every 2400 contrast studies of the upper gastrointestinal tract [1]. Most are posterior and near the gastroesophageal junction, which likely reflects a congenital origin [2]. In this location, a gastric diverticulum typically appears as a thin-walled gas and fluid-filled mass measuring 1–5 cm in diameter above the left kidney (Figures 36.1 and 36.2).

Importance

A gastric fundal diverticulum, especially if filled only with fluid and not air and fluid, may mimic a cystic retroperitoneal or adrenal mass at cross-sectional imaging (Figures 36.3 and 36.4) [2, 3].

Typical clinical scenario

While gastric diverticula are usually incidental and asymptomatic, complications such as bleeding, polyp formation, and malignancy (Figure 36.5) have been reported [4–7].

Differential diagnosis

An air and fluid-filled gastric diverticulum has a very limited differential diagnosis. Conceivably a retroperitoneal abscess or super-infected cystic tumor might be considerations, though it is most likely these entities would be thick-walled and the patient would be septic – strong clues to the correct diagnosis. A purely fluid-filled gastric diverticulum can be difficult to distinguish from benign or malignant retroperitoneal tumors such as lymphangioma or sarcoma. CT with positive oral contrast can then be helpful in establishing the correct diagnosis (Figures 36.3 and 36.4).