Gastric neoplasia best treated surgically

source-image
Nov 01, 2003

Signalment: Canine, Labrador Retriever/Collie cross, 7 years old, male neutered, 57 lbs.

Clinical history: The dog presents with poor appetite and moderate lethargy for two months and weight loss. The results of the Ehrlichia canis and Lyme disease tests are negative and the Rocky Mountain spotted fever test is positive at 1:128. Therapy has included tetracycline.

Physical examination: The findings include rectal temperature 102.6° F, heart rate 120/min, slightly pale mucous membranes, and normal capillary refill time. Normal heart and lung sounds are heard. Abdominal distension, thinness, and generalized muscle wasting are noted.

Laboratory results: A complete blood count, serum chemistry profile and urinalysis are outlined in Table 1.

Ultrasound examination: Thorough abdominal ultrasonography was performed.


Table 1: Results of laboratory tests
My comments: There is a moderate amount of free fluid accumulated within the abdominal cavity. The liver shows a uniform echogenicity in its parenchyma. No masses noted within the liver parenchyma. The gall bladder is mildly distended, and its walls are not thickened or hyperechoic. The spleen shows a uniform echogenicity in its parenchyma - no masses noted. The left and right kidneys are similar in size, shape and echotexture. No masses or calculi were noted in either kidney. The urinary bladder is distended with urine and contains some urine sediment material - no masses or calculi noted. The left and right adrenal glands are similar in size and shape. The stomach wall is irregularly thickened and echobright. The small intestinal wall is normal. The pancreas is enlarged.

Cytologic examination: About 1,300 milliliters of ascitic fluid was removed prior to further ultrasonographic evaluation. Fine needle aspirations of the stomach wall and sample of ascitic fluid for cytologic examination were collected and submitted for laboratory evaluation.

The cytologic results indicate gastric wall adenocarcinoma and neoplastic effusion secondary to disseminated carcinoma (carcinomatosis).

Case management: In this case, gastric wall adenocarcinoma with metastatic spread is the clinical diagnosis. Clinically, there is not much one can do for this case with this histopathologic diagnosis. Chemotherapy may be attempted but carries a grave prognosis.


Image 1.
Review of gastric neoplasia Gastric neoplasia accounts for less than 1 percent of all canine malignancies. Adenocarcinoma is the most common type, affecting older (average age between 7.5 to 10 years) male dogs.

Other malignant tumors include leiomyosarcoma and lymphoma. Benign tumors (adenomas and leiomyomas) are uncommon and affect older dogs (average age being 16 years).


Image 2.
Lymphosarcoma is the most common gastric neoplasm in cats. Gastric adenocarcinomas are most common on the lesser curvature and pylorus and often involve most of the gastric body. Metastases are common, especially in the gastric lymph nodes, but also in the spleen, liver, omentum, peritoneum and lungs. Gastric lymphosarcoma may appear as a single mass or multiple, often ulcerated nodules, or as a diffuse infiltrative lesion. Regional lymph nodes are often involved. Adenomas present as polypoid masses, which may occlude the pylorus. Leiomyomas present as single or multiple sessile, firm polyps, covered by a normal mucosa. They are localized in the gastric body or near the cardia.

Diagnostic considerations Dogs with gastric adenocarcinoma usually present with vomiting, anorexia and weight loss. The duration of clinical signs is from weeks to months. Definitive diagnosis of neoplasia requires full-thickness biopsy of the stomach. However, a tentative diagnosis may be made based on supportive signalment and history. Clinical pathology findings are inconsistent. Pre-renal azotemia, hypokalemia, hypochloremia, metabolic alkalosis, anemia and hypoalbuminemia can occur because of chronic vomiting.


Image 3.
Metabolic abnormalities are uncommon as most animals suffer low-grade, chronic vomiting. However, severe and protracted vomiting may be associated with metabolic alkalosis and paradoxical aciduria.

Survey and contrast radiography, endoscopy and ultrasonography may be used in the diagnosis of gastric adenocarcinoma in dogs.