Diagnosis of canine gastric adenocarcinoma using squash preparation cytology

Adenocarcinoma is the most common gastric tumour in dogs. Clinical signs and laboratory results are often non-specific, with histopathological examination of gastric biopsies being required to reach a de- finitive diagnosis. Use of cytology would potentially shorten the time to diagnosis and allow early interventional measures to be implemented. However, there are relatively few studies of the cytological features of gastric samples. The present study was designed to investigate whether cytology might be useful for diagnosis of canine gastric adenocarcinomas and to evaluate the performance of squash prep- aration cytology for this purpose. Squash preparations of gastric biopsies from 94 dogs were reviewed to determine the presence or absence of specific cytological features associated with adenocarcinomas and to compare findings with the results of histopathological examination of gastric biopsies. The pres- ence of signet ring cells, microvacuolation, cellular pleomorphism and single cell distribution of epithe- lial cells were positively associated with a diagnosis of gastric adenocarcinoma. Combined evaluation (parallel testing) for the presence of signet ring cells and microvacuolation demonstrated excellent results for recognition of adenocarcinomas. Cytological examination of squash preparations from gastric biop- sies and identification of signet ring cells and cytoplasmic vacuolation can allow rapid and reliable di- agnosis of canine gastric adenocarcinomas.