Ultrasonographic features of gastric mucosal hypertrophy in dogs receiving chronic omeprazole: a retrospective case series

Objective: To describe ultrasonographic features of gastric mucosal abnormalities in dogs receiving chronic omeprazole therapy. Methods: Medical records from a veterinary teaching hospital were retrospectively reviewed to identify dogs evaluated between 2020 and 2026 with a history of chronic (≥ 5 months) omeprazole administration that had undergone abdominal ultrasonography. Dogs were included if ultrasonography demonstrated gastric wall abnormalities consistent with a defined pattern. Nine dogs met the inclusion criteria. Dogs were medium to large breed and receiving omeprazole for management of portosystemic shunting, gastric ulceration, or chronic enteropathy. Ultrasonographic findings were descriptively reviewed, and available histopathology was assessed. Results: All 9 dogs demonstrated gastric wall changes characterized by predominantly mucosal involvement. Abnormalities were localized to the gastric body and fundus in all dogs and were circumferential in 7 and focal in 2. The mucosa was hyperechoic and mildly heterogeneous with undulating margins and thickened rugal folds. Small intramucosal hypoechoic to anechoic round structures were identified in 4 dogs. Gastric wall layering was preserved in 8 dogs, with no regional lymphadenopathy or perigastric abnormalities. Differential diagnoses included severe gastritis, infiltrative gastric neoplasia, mural hemorrhage, and hypertrophic gastropathies. Histopathology, available in 4 dogs, supported a PPI-associated hypertrophic mucosal phenotype characterized by mucous neck cell hyperplasia. Conclusions: Chronic omeprazole administration in dogs was associated with a consistent ultrasonographic pattern of mucosal-predominant gastric wall changes. Clinical Relevance: Recognition of this pattern may help differentiate medication-associated changes from more aggressive disease processes and guide diagnostic decision-making.