JPC SYSTEMIC PATHOLOGY
Signalment (JPC #2558677): 9-month old female beagle
HISTORY: Incidental necropsy finding in a beagle used in a toxicology study.
HISTOPATHOLOGIC DESCRIPTION: Jejunum: Multifocally replacing intestinal mucosa are several well-demarcated foci, up to 1.5 mm wide, of gastric mucosa composed of tightly packed tubular glands lined by cuboidal cells with basally positioned nuclei and apical, lightly eosinophilic, foamy cytoplasm (chief cells) or with round nuclei and abundant eosinophilic, granular cytoplasm (parietal cells). Diffusely, remaining villi and crypts are lined by markedly increased numbers of goblet cells (goblet cell hyperplasia).
MORPHOLOGIC DIAGNOSIS: Jejunum: Heterotopic fundic gastric mucosa, multifocal, segmental, with diffuse goblet cell hyperplasia, beagle, canine.
CONDITION: Gastric heterotopy (choristoma)
- Extremely rare in animals but has been reported in the dog and cat
- Choristoma is defined as normal mature tissue in an ectopic location
- A survey of 365 beagle dogs found 4.1% affected, with higher incidence in males
- Most commonly involves ectopic gastric or pancreatic tissue in the intestines, with one report of intestinal choristoma in the subcutis
- It was the site of development of a gastric adenocarcinoma in one beagle
- Congenital rest of normal gastric mucosa
- Can occur at any level of the gastrointestinal tract
- The site in one report coincided with the usual site of Meckel’s diverticulum
TYPICAL CLINICAL FINDINGS:
TYPICAL GROSS FINDINGS:
- Round or oval ulcerous or crateriform, usually solitary foci at the antimesenteric border of the small intestine
TYPICAL LIGHT MICROSCOPIC FINDINGS:
- Islets of histologically normal well circumscribed gastric mucosa (surface mucus cells, chief cells, parietal cells and mucus neck cells of the stomach) replacing small intestinal mucosa; adjacent small intestine is normal
- Submucosal and muscular layers are a continuation of the corresponding layers of the small intestine
- Goblet cell hyperplasia in adjacent mucosa may be a protective response to gastric acid secretion by the heterotopic tissue
ADDITIONAL DIAGNOSTIC TESTS:
- None; diagnosis based on histology
- Intestinal neoplasms
- Hyperplastic polyps
- Inflammation (pythiosis)
- Subcortical heterotopia in a California sea lion due to a neuronal migration defect was reported in 2008
- Heterotopic kidney tissue in the lung of a dolphin has been reported
- Two Siamese cats with heterotopic gastric mucosa within the mucosa of dilated esophagi have been reported
- Occurs in esophagus, thoracic and abdominal cysts, bile duct, gallbladder, intestinal tract and intestinal diverticula in humans
- World Health Organization International Histological Classification of Tumors of Domestic Animals. Vol X. Second Series. Armed Forces Institute of Pathology; 2003:108-109.
- Iwata H, Arai C, Koike Y, et al. Heterotopic gastric mucosa of the small intestine in laboratory beagle dogs. Toxicol Pathol. 1990;18:373-379.
- Kusewitt D. Neoplasia and tumor biology. In: Zachary JF, McGavin MD, eds, Pathologic Basis of Veterinary Disease. 5th ed. St. Louis, MO: Elsevier; 2012: 291.
- Maitra A, Kumar V. Diseases of infancy and childhood.In: Kumar V, Abbas AK, Fausto N, Aster JC, eds. Robbins and Cotran Pathologic Basis of Disease. 8th ed. Philadelphia, PA: Saunders Elsevier; 2015: 267,473.
- Panigrahi D, Johnson AN, Wosu NJ. Adenocarcinoma arising from gastric heterotopia in the jejunal mucosa of a beagle dog. Vet Pathol. 1994;31:278-80,