Aggressive Hepatocellular Carcinoma with Paraneoplastic Hypercalcemia in a Dog: A Case of Advanced Multilobular Malignancy

Background: Hepatocellular carcinoma (HCC) represents the most common primary malignant liver tumor encountered in dogs. Although surgical resection remains the treatment of choice for the majority of solitary masses, the prognosis is frequently guarded for the nodular or diffuse subtypes, which inherently carry a higher metastatic potential. This report documents a particularly challenging clinical presentation of HCC, distinguished by marked systemic abnormalities and overt features of advanced malignancy. Methods: An ۸-year-old male neutered mixed-breed dog was admitted with a three-day history of pronounced anorexia, vomiting, lethargy, and restlessness. Initial diagnostic workup included a Complete Blood Count (CBC) and a serum biochemical analysis. Abdominal ultrasound revealed a substantial mass localized to the left lateral liver lobe, alongside distinct nodular masses in other lobes and clearly enlarged mesenteric lymph nodes, strongly suggesting metastasis. The patient subsequently underwent exploratory laparotomy and an excisional biopsy for definitive histopathological evaluation. Results: The CBC identified notable leukocytosis, accompanied by reduced red blood cell counts and diminished hemoglobin levels. Serum biochemistry showed striking elevation of liver enzyme activities: ALP (۱۷۸۸ U/L), ALT (۱۴۵ U/L), AST (۱۲۳ U/L), and GGT (۲۱.۶ U/L). A critical and telling finding was the mildly elevated calcium level (۱۲.۰ mg/dL), which pointed strongly toward a paraneoplastic syndrome, concurrent with moderate azotemia (۲۹.۶ mg/dL). Histopathology described a poorly differentiated malignant neoplasm exhibiting pronounced pleomorphism and the unequivocal finding of vascular invasion. The tissue was ultimately diagnosed as Hepatocellular Carcinoma with established features of advanced malignancy. Regrettably, the patient passed away two days following the surgical procedure. Conclusion: This case highlights the aggressive nature of poorly differentiated HCC in canines, with severe systemic paraneoplastic effects, multifocal gross disease, and definitive histopathology indicating advanced malignancy and a guarded to poor prognosis due to the advanced stage of malignancy.

کلیدواژه ها:

Hepatocellular Carcinoma ، Paraneoplastic Hypercalcemia ، Vascular Invasion ، Poorly Differentiated ، Canine Oncology