Primary Hepatic Masses in Ten Dogs: A Retrospective Surgical Case Series

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 lesions 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 a definitive histological diagnosis. Tumor size ranged from 3.3 to 18 cm. Both benign and malignant lesions were represented across this size range. Cytological findings were discordant with the final histopathological diagnosis in three dogs, whereas one sample was non-diagnostic due to blood contamination. Abdominal ultrasound identified solitary lesions in all evaluated dogs, although surgery revealed previously undetected multifocal disease in two cases. Six of the ten lesions involved the right medial hepatic lobe, although the small sample size precludes conclusions regarding lesion distribution. All dogs underwent surgical resection. Two perioperative deaths occurred secondary to postoperative renal failure. Among the surviving dogs, clinical status during follow-up was generally reported as improved compared with preoperative presentation, and survival times ranged from 4 to more than 730 days, including dogs with malignant neoplasms. Four dogs remained alive and disease-free at the end of the follow-up period (>730 days). This retrospective case series illustrates the clinical and pathological heterogeneity of primary hepatic masses in dogs. Discrepancies between preoperative assessment and intraoperative or histopathological findings were observed in some cases. Given the small sample size, heterogeneous diagnoses and non-standardized diagnostic workup, these observations should be interpreted cautiously and considered hypothesis-generating.