abs: Clinical Utility of Cytology from Preoperative Percutaneous Fine Needle Aspirates of Solitary Liver Masses in 220 Dogs: A Retrospective Study (2009-2019)
_{Small Animal Flash Poster Presentations}

When a solitary liver mass is identified in a dog a fine-needle aspirate (FNA) is commonly employed to attempt to obtain a diagnosis. Little information is provided in the literature evaluating the sensitivity/specificity of FNA cytology for solitary liver masses. We hypothesized that liver lesion size nor the presence of cavitation would impact the success of cytological diagnosis. Medical records were obtained for 220 client-owned dogs. Inclusion criteria included preoperative abdominal imaging, percutaneous FNA of a solitary hepatic mass with cytologic interpretation by a board-certified pathologist, and a surgical biopsy or mass excision yielding a histopathological diagnosis. Six dogs (2.7%) experienced a complication after FNA, none considered severe. The agreement rate for correct cytologic diagnosis was 22.9% (49/220). Of the neoplastic masses, 18.9% (35/185) were correctly diagnosed via cytology. The overall sensitivity was 60% and specificity was 68.6%. Neither institution (P=0.16), lesion size (P=0.88), cavitation (P=0.34), or needle gauge (P=0.20) had an association with correct diagnosis. There were several inherent limitations relating to the retrospective nature, including variability of completeness of medical record information, lack of standardization with FNA procedure as these were performed by different doctors and hospitals, as well as lack of standardization of interpretation of cytological results as these were performed by different pathologists. This study demonstrates while there is a low risk of complications following FNA of a hepatic mass, overall success rate for correct cytologic diagnosis based on FNA was low compared to histopathologic diagnosis.