Left Medial Liver Lobe Torsion Associated With Hepatocellular Carcinoma in a Pembroke Welsh Corgi: A Case Report.

Liver lobe torsion (LLT) is a rare, potentially life-threatening condition in dogs and is reported most often in medium- to large-breed dogs. Neoplasia-associated LLT is unusual, and detailed descriptions of LLT associated with hepatocellular carcinoma (HCC) are scarce. A 12-year-old spayed female Pembroke Welsh Corgi (9.5 kg) presented with acute collapse after several months of progressive lethargy and inappetence. Laboratory abnormalities included increased alanine aminotransferase and aspartate aminotransferase activities and C-reactive protein concentration. Computed tomography (CT) identified a 7.2 × 6.7 × 6.5 cm mass arising from the left medial liver lobe, a whirl sign at the base of the mass and a non-enhancing hypoattenuating region consistent with necrosis. Midline celiotomy and left medial liver lobectomy were performed without detorsion. Cytology of abdominal effusion was consistent with a culture-negative inflammatory exudate. Histopathology confirmed HCC with extensive necrosis, and the examined surgical margin was free of neoplastic cells. The dog recovered uneventfully, was discharged on postoperative Day 4 and had no recurrence of clinical abnormalities at 1-year follow-up. This case highlights the apparent association between HCC and LLT and the unusual location of the torsion axis at the base of the mass rather than at the hepatic hilus, although causality cannot be established from a single case. CT visualisation of the whirl sign at this atypical site was instrumental in establishing the preoperative diagnosis and guiding surgical planning.