Zoe Belshaw, MA Vet MB Cert SAM MRCVSHills' Resident in Small Animal Internal Medicine, QVSH, Cambridge.
Gastric adenocarcinomas account for 42-72% % of canine malignant gastric tumours (Swann and Holt 2002). The commonest presenting signs are vomiting, anorexia and weight loss (Swann and Holt 2002). This abstract reports atypical presentation of gastric carcinoma in two dogs referred to QVSH, Cambridge.
Case 1 was a 5 year old male neutered Belgian Shepherd dog referred with a 2 week history of anorexia and weight loss. On examination, the dog was in poor body condition (BCS 3/9), demonstrated marked ptyalism and extreme discomfort on palpation of the pharynx with intermittent bruxism. He had bilaterally enlarged firm and painful submandibular salivary glands. Oral examination revealed multifocal ulceration around the edge of the tongue. The remainder of a general clinical examination was unremarkable. The dog was initially investigated for oro-pharyngeal disease. Haematology, biochemistry, pharyngeal examination under anaesthesia, and thoracic and abdominal imaging failed to provide a diagnosis. Upper gastrointestinal endoscopy and biopsies of the pharynx were similarly unrewarding. A PEG tube was placed under anaesthesia on day 2 to allow nutritional support and the dog was analgesed with methadone and lignocaine but became progressively more painful over the following 12 days. Multiple investigations conducted over this period failed to find a cause for the signs and the dog continued to lose weight despite adequate nutrition. The tongue lesions progressed and emesis developed on day 11. He was euthanased on day 12. Post mortem examination revealed a submucosal gastric adenocarcinoma at the cardia mixed with a florid schirrous stromal reaction. The tongue lesions were necrosis due to thromboemboli.
Case 2 was a 12 year old male neutered Labrador cross who presented with a two month history of acute onset retching and ptyalism following a 6 month history of chronic intermittent emesis. Salivary gland biopsies had revealed sialitis but the dog had been unresponsive to antibiotics or prednisolone. On examination he was in poor body condition (BCS 2/9) and again had marked pain on palpation of the pharynx and salivary glands. Oral examination revealed bilateral ulceration of the buccal mucosa. Cranial abdominal palpation caused discomfort but no further abnormalities were detected. Based on the similarities to case 1, abdominal imaging was performed as part of the initial investigations. This revealed focal thickening of the greater curvature of the stomach with associated lymphadenopathy, an irregular pancreas and mottled spleen. Splenic aspirates revealed rafts of carcinoma cells. His owners requested euthanasia at this point. Post mortem examination confirmed a gastric carcinoma with pancreatic and splenic metastasis.
Ptyalism is rarely reported in association with canine gastric carcinoma (Swann and Holt 2002). The pharyngeal pain associated with these cases has not been previously documented. Thromboembolic disease is a well recognised consequence of gastric carcinoma in humans and is thought to be due to mucin released from the neoplastic cells leading to aberrant platelet activation and subsequent thrombosis (Tetzlaff and others 2007) but is again unreported in dogs. Based on these cases, gastric carcinoma should be included as a differential diagnosis for oral ulceration and pharyngeal pain.
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Tetzlaff ED, Correa AM, Baker J, Ensor J and Ajani JA (2007) The impact on survival of thromboembolic phenomena occurring before and during protocol chemotherapy in patients with advanced gastroesophageal adenocarcinoma Cancer 109(10):1989-1995