Discrepancies between Preoperative Assessment and Surgical Reality in Canine Hepatic Masses: A Retrospective Study of 10 Cases with a Predominance of Right-Sided Lesions

Primary hepatic masses in dogs represent a heterogeneous group of lesions with variable biological behavior and challenging preoperative characterization. The objective of this retrospective study was to describe the clinical presentation, diagnostic findings, surgical management, and outcome of dogs with primary hepatic masses treated surgically. Ten dogs with resectable hepatic lesions and no evidence of extrahepatic metastasis were included. Clinical records, imaging findings, histopathological diagnoses, treatment, and follow-up data were reviewed. Histopathological diagnoses included hepatocellular carcinoma (n=3), nodular hyperplasia (n=2), lobular hyperplasia (n=1), hepatocellular adenoma (n=1), undifferentiated sarcoma (n=1), osteosarcoma (n=1), and one case without definitive histological diagnosis. Tumor size ranged from 3.3 to 18 cm and was not associated with biological behavior. Preoperative cytology showed poor concordance with final histopathological diagnosis in all sampled cases. Abdominal ultrasound identified solitary lesions in all evaluated dogs, although surgery revealed previously undetected multifocal disease in two cases. Most lesions were located in the right hepatic lobes, differing from the predominance of left-sided lesions commonly reported in the literature. All dogs underwent surgical resection. Two perioperative deaths occurred secondary to postoperative renal failure. In the remaining dogs, surgery resulted in complete remission of clinical signs and prolonged survival, including dogs with malignant tumors. Four dogs remained alive and disease-free at the end of the follow-up period (>730 days). These findings highlight the limitations of preoperative diagnostic techniques for predicting the biological behavior and extent of canine hepatic masses. Surgical resection provided substantial clinical benefit and prolonged survival in most cases, supporting its consideration whenever complete excision is technically feasible.