Species: Beagle dog Strain/breeder: Own breed Sex: Female Age: 10 months Study type: 3 month feeding study Treatment: Control Animal status: Scheduled sacrifice, end of study Clinical findings: None Organ(s): Esophagus (with transition to cardia) Macroscopic finding(s): None Staining: H&E / Alcian blue

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Abstract

W. KAUFMANN

BASF AG, Department of Product Safety, Regulations, Toxicology and Ecology, GV/T, Z 470, 67056 Ludwigshafen, Germany

Key words: ectopia, gastric mucosa, oesophagus, beagle dog, Barrett's oesophagus

During routine histological examination of the dog's stomach at the transition from the cardia to the oesophagus, an island of columnar mucosa was present within the stratified squamous epithelium of the oesophagus, relatively far from the oesophago-gastric junction.

This rare, spontaneous lesion has not previously been diagnosed in beagle studies in our laboratory. However, mucosal metaplasias in the distal part of the oesophagus are described in the literature as a result of long-standing gastro-oesophageal reflux disease in humans. Such metaplastic lesions are called "Barrett's mucosa" or "Barrett's metaplasia", respectively. It became an issue of interest as the Barrett's metaplasia represents a transformed nonautochthonous mucosa which is genetically unstable and has a tendency to malignant transformation. Different grades, from "normal" Barrett's mucosa (so called low-grade dysplasia, which is potentially reversible) to high-grade dysplasias with precarcinomatous histological features are described.

In our case, the columnar mucosa expressed no malignant histopathological features. Thus, an "ectopia of gastric mucosa" in the oesophagus as a developmental malformation in beagle dogs may be a more appropriate diagnosis for this lesion instead of "Barrett's mucosa".