Page 916 - Cote clinical veterinary advisor dogs and cats 4th

Hepatic Neoplasia, Malignant 447

• Feline primary hepatic neoplasms can be HISTORY, CHIEF COMPLAINT times are not common (when coagulopathies
subdivided into benign and malignant Clinical signs are usually vague and nonspe- occur, they are most common with hepatic
VetBooks.ir cinomas, small cell carcinomas with hepatic dipsia, polyuria, vomiting, and abdominal • Serum chemistry profile: mild to marked Diseases and Disorders
cific. Inappetence, lethargy, weight loss, poly-
hemangiosarcoma).
hepatocellular tumors, cholangiocellular car-
increases in activities of alanine aminotrans-
distention are the most common presenting
progenitor cell characteristics, neuroendocrine
carcinomas, and squamous cell carcinomas.
are icterus, diarrhea, excessive bleeding, and
• Biliary carcinomas and adenomas are the complaints. Less frequent presenting problems ferase (ALT), aspartate aminotransferase
(AST), and alkaline phosphatase (ALP).
most common primary hepatic tumors in signs of central nervous system (CNS) dys- ALP and ALT are more commonly elevated
cats. Biliary tumors account for 22%-41% function (due to HE, hypoglycemia, or CNS in primary hepatic tumors and AST more
of malignant liver tumors in dogs. metastases). commonly elevated in metastatic tumors.
• Tumors occur primarily in older animals Liver enzyme activities are normal in up to
(average age, 10-12 years). PHYSICAL EXAM FINDINGS 50% of dogs with metastatic tumors. Hyper-
• The most common finding in dogs and bilirubinemia (uncommon in dogs with
RISK FACTORS cats with primary hepatic tumors is a primary hepatic neoplasia, more common in
• Potential causes in humans include cirrhosis, palpable cranial abdominal mass or marked dogs with metastatic liver disease) occurs in
toxins, chemicals, parasites, viruses, and hepatomegaly. one-third of cats with primary liver tumors.
radioactive compounds. • Ascites or hemoabdomen may also contribute Other biochemical abnormalities may include
• Biliary carcinoma in juvenile cats with feline to abdominal distention. hypoalbuminemia, hyperglobulinemia, and
leukemia virus infection • Icterus, cachexia, weakness, and pale mucous hypoglycemia.
• Cirrhosis occurred in 7% of dogs with membranes due to anemia are potential • Serum bile acids concentration: elevated
HCC in one study; it is therefore an findings. in 50%-75% of cases, often with mild
unlikely contributor to development of • Exam may be unremarkable. magnitude of increase
HCC in dogs. There is no known viral • Abdominal radiographs: symmetrical or
association with primary hepatic neoplasia Etiology and Pathophysiology asymmetrical hepatomegaly, ascites, and
in dogs. • Cause is unknown. caudolateral gastric displacement
• The more common massive HCCs in dogs • Three-view thoracic radiographs: evaluate
ASSOCIATED DISORDERS generally have a low potential for metastasis, for pulmonary metastasis, although this is
• Paraneoplastic hypoglycemia is occasion- with rates varying from 0%-37%. The less an uncommon finding at the time of initial
ally seen in dogs with HCC (up to 38% common nodular and diffuse HCCs have diagnosis.
of cases) and less frequently in dogs with metastatic rates as high as 100%. • Abdominal ultrasound: very useful for
hepatocellular adenoma, leiomyosarcoma, or • Extrahepatic metastases occur more evaluation of the liver when primary or
hemangiosarcoma. Serum insulin concentra- commonly with biliary carcinoma, with metastatic hepatic neoplasia is suspected.
tions are normal to decreased. metastasis occurring in 67%-88% of dogs However, there can be extensive variability
• Paraneoplastic alopecia has been reported in and cats. and overlapping ultrasonographic appearance
cats with biliary carcinoma and HCC. • Metastasis is common for hepatic carcinoids. among neoplastic and non-neoplastic condi-
• Bile duct obstruction, clinically relevant • Metastatic rates of 86%-100% for hepatic tions. Caution is warranted when attempting
coagulopathies, and hepatic encephalopathy sarcomas in dogs to use ultrasound alone to diagnose hepatic
(HE) are uncommon. • Metastatic patterns are to regional lymph lesions:
• Myasthenia gravis was associated with biliary nodes, peritoneum, and lungs, and can ○ HCC usually appears as a focal hyperechoic
carcinoma in one report. be widespread to other abdominal organs. or mixed echogenic mass.
Metastasis to bone marrow can occur with ○ Primary or metastatic neoplasia often
Clinical Presentation histiocytic sarcoma. appears as focal or multifocal hypoechoic
DISEASE FORMS/SUBTYPES or mixed echogenic lesions.
HCC: three gross morphologic subtypes: DIAGNOSIS ○ Target lesions, nodules or masses with
• Massive HCC, defined as a large tumor a hypoechoic rim and a hyperechoic or
affecting a single liver lobe, represents Diagnostic Overview isoechoic center, are often neoplastic, with
53%-83% of cases. The nodular form occurs The diagnosis is typically based on the presence a positive predictive value for malignancy
in 16%-25%, and the diffuse form occurs of a liver mass/masses that are palpated and/ of 74% for solitary lesions and 81% for
in 0%-19% of cases. or identified on abdominal ultrasound exam. multiple lesions.
• Histopathologic and immunohistochemical Confirmation is by cytologic or histopathologic ○ Hyperplastic nodules are usually multifocal
exam of canine primary hepatic neoplasms exam of tissue specimens. hyperechoic lesions, although hypoechoic
can differentiate hepatocellular, cholan- or mixed echogenic lesions can occur.
giocellular and neuroendocrine tumors in Differential Diagnosis ○ The ultrasonographic appearance of
accordance with the most recent human • Hepatic nodular hyperplasia (p. 449) hepatic lymphoma is quite variable,
classification system and may be predictive • Diffuse hepatomegaly (e.g., vacuolar hepa- ranging from normal to mild, diffuse
of biologic behavior. topathy, hepatic congestion, lipidosis) hyperechogenicity or hypoechogenicity,
Biliary carcinoma in dogs: • Hepatic nodular regeneration, cirrhosis multifocal hypoechoic lesions, or mixed
• Massive form occurs in 37%-46%, nodular in • Hepatobiliary cysts echogenic target lesions.
0%-54%, and diffuse in 17%-54% of cases. • Hepatic abscess ○ Contrast harmonic ultrasound can dis-
Biliary carcinomas can also be extrahepatic criminate between benign and malignant
within bile ducts or gallbladder. Initial Database nodules in the canine liver. This method
Carcinoid: • CBC: variable anemia, leukocytosis, and requires ultrasound contrast media and
• Usually intrahepatic, although can be thrombocytosis. Pancytopenia may be seen contrast harmonic software. Results
extrahepatic in the gallbladder with hemolymphatic malignancies that depend on operator experience with this
• Nodular in 33%, diffuse in 67% involve bone marrow and secondarily involve modality.
Sarcoma: the liver. ○ The ultrasound exam should assess for
• Massive in 36%, nodular in 64%; diffuse • Coagulation profile: prolonged prothrombin feasibility of resection (relationship to vena
form not reported times and activated partial thromboplastin cava, portal vein, and biliary tract).

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