Feline neuroendocrine epithelial tumors
Feline tumors arising from the neuroendocrine epithelium of hepatic and biliary tissues have been reported.45 The average age is 9 years, and males are overrepresented (Table 2). The clinical signs are similar to those seen with other hepatobiliary diseases; however, less than 30% of cats have a palpable
abdominal mass (Table 4). More than 50% of cats with biliary neuroendocrine tumors are icteric, with elevations in AST, ALP, and ALT activities.
Conversely, cats with hepatic neuroendocrine tumors rarely have marked biochemical changes.
Table 4 Selected Clinical Features of Primary Feline Hepatobiliary Tumors*
Treatment for feline neuroendocrine tumors remains anecdotal, but attempted surgical resection has been reported. In one study,
more than 80% of cats died or were euthanized soon after surgery. Metastasis—most often involving the lymph nodes, lungs,
or intestines or with evidence of peritoneal carcinomatosis—was identified in all the cats in which necropsy information was
Feline hepatocellular carcinomas
Feline hepatocellular carcinomas account for up to 17% of hepatobiliary tumors. Clinical findings, diagnostic tests, and treatment
are similar to that of other hepatobiliary tumors. Pulmonary and splenic metastases have been rarely documented.38,39
Feline hepatic sarcomas
Primary hepatic sarcomas are uncommon in cats, but fibrosarcoma, hemangiosarcoma, osteosarcoma, leiomyosarcoma, and rhabdomyosarcoma
have been reported.8,14,15,38
Although specific clinical signs such as a palpable liver mass or icterus may indicate a primary hepatobiliary tumor, signs
and abnormalities in blood work may often be nonspecific. Thus, dogs and cats with hepatobiliary neoplasia may have advanced
disease at the time of diagnosis. Cytology, tissue biopsy, and the use of advanced imaging such as MRI and CT can help you
determine whether liver lesions are benign or malignant. In dogs, most tumors are malignant, while benign tumors are more
common in cats.
Although a patient's prognosis depends on many factors, including tumor histologic type, the degree of parenchymal involvement,
and metastatic disease, excisional surgery and supportive care remain the primary therapeutic options for all hepatobiliary
tumors in dogs and cats. Through the use of advanced imaging modalities, hepatobiliary tumors may be more readily diagnosed
in companion animals. In turn, the early detection of liver cancer may permit prompt institution of treatment, ultimately
improving the survival outcomes for dogs and cats with liver cancer.
Jackie Wypij, DVM
Timothy M. Fan, DVM, DACVIM (oncology, internal medicine)
Louis-Philippe de Lorimier, DVM, DACVIM (oncology)
Department of Veterinary Clinical Medicine
College of Veterinary Medicine
University of Illinois
Urbana, IL 61802
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