Changes

==Description==

==Description==

Primary hepatic tumours are rare, accounting for less than 1.5% of all canine tumours and 1.0-2.9% of all feline tumours. However, the liver is a common site for metastatic tumours due to its rich blood supply from the hepatic portal vein and hepatic artery and in dogs, hepatic neoplasia are 2.5 times more likely to be metastases than primary neoplasia.  By contrast, primary hepatobillary tumours are more frequent than metastatic tumours in cats.

Primary hepatic tumours are rare, accounting for less than 1.5% of all canine tumours and 1.0-2.9% of all feline tumours. However, the liver is a common site for the establishment of metastatic tumours due to its rich blood supply from the hepatic portal vein and hepatic artery.  In dogs, hepatic neoplasia are 2.5 times more likely to be metastases than primary neoplasia whereas primary hepatobillary tumours are more frequent than metastatic tumours in cats.

Malignant tumours are more common in dogs but benign neoplasia is more common in cats.  Primary tumours found in the liver include:

Malignant tumours are more common in dogs but benign neoplasia are more common in cats.  Primary tumours found in the liver include:

* [[Carcinoma#Hepatocytic|Hepatocellular carcinoma]] or [[Adenoma#Hepatocytic|adenoma]] (hepatoma)

* [[Carcinoma#Hepatocytic|Hepatocellular carcinoma]] or [[Adenoma#Hepatocytic|adenoma]] (hepatoma)

* [[Carcinoma#Cholangiocellular|Cholangiocellular carcinoma]] or [[Adenoma #Cholangiocellular|cystadenoma]]

* [[Carcinoma#Cholangiocellular|Cholangiocellular carcinoma]] or [[Adenoma #Cholangiocellular|cystadenoma]]

* Mast cell tumour

* Mast cell tumour

* Hepatic carcinoids (neuroendocrine)

* Hepatic carcinoids (neuroendocrine)

* Benign tumours include:

* Lymphoma

Care must be taken to distinguish between all hepatic tumours and [[Liver - Nodular Hyperplasia|benign nodular hyperplasia]] which is frequently observed in older dogs. The most significant primary tumours in the dog are hepatomas, [[Carcinoma #Hepatocytic|hepatocellular]] and [[Carcinoma#Cholangiocellular|cholangiocellular]] carcinomas and hepatic carcinoids. [[Carcinoma#Hepatocytic|Hepatocellular carcinomas]] and  [[Carcinoma#Cholangiocellular|cholangiocellular carcinomas]] are the most significant in cats.  

Care must be taken to distinguish between all hepatic tumours and [[Liver - Nodular Hyperplasia|'''benign nodular hyperplasia''']] which is frequently observed in older dogs. The most significant primary tumours in the dog are hepatomas, [[Carcinoma #Hepatocytic|hepatocellular]] and [[Carcinoma#Cholangiocellular|cholangiocellular]] carcinomas and hepatic carcinoids. [[Carcinoma#Hepatocytic|Hepatocellular carcinomas]] and  [[Carcinoma#Cholangiocellular|cholangiocellular carcinomas]] are the most significant tumours to occur in cats.  

==Signalment==

==Signalment==

===Hepatocellular Tumours ([[Carcinoma#Hepatocytic|Hepatocellular carcinomas]] (HCC) and [[Adenoma#Hepatocytic|Hepatomas]])===

===Hepatocellular Tumours===

* HCC occurs more frequently in dogs and hepatomas more commonly in cats. They are the most common primary liver tumour in dogs and the second most common in cats.  

Hepatocellular tumours include [[Carcinoma#Hepatocytic|hepatocellular '''carcinomas''']] (HCC) and [[Adenoma#Hepatocytic|'''hepatomas''']].  HCC occurs more frequently in dogs but hepatomas are more common in cats. These are the most common primary liver tumour in dogs and the second most common in cats.  

Male dogs over 10 years old are most frequently affected by HCC and the Miniature schnauzer breed may be predisposed to the disease. The metastatic rate of hepatocellular tumours depends on the nature of the mass, with massive tumours spreading at a rate of 0-37% and nodular or diffuse tumours metastasising in 93-100% of cases. The most common sites of metastasis are the regional lymph nodes (the hepatic and diaphragmatic nodes), the peritoneum and lungs. [[Adenoma#Hepatocytic|Hepatomas]]) are usually incidental findings but they may cause hypoglycaemia as a paraneoplastic syndrome.

* Bile duct carcinomas are the most common malignant hepatobillary tumours in cats and the second most frequent in dogs and females may be predisposed

* Intrahepatic carcinomas are more frequent in dogs. In cats there have been reports of both equal occurrence of intra-and extrahepatic tumours and of a extrahepatic dominance.

* Bile duct carcinomas are aggressive with metastasis to particularly the regional lymph nodes and lungs frequently being observed in dogs and diffuse intraperitoneal metastasis and carcinomatosis being common in cats.

* Bile duct adenomas (also known as biliary or hepatobiliary cystadenomas) are common in cats, particularly males.

===Carcinoids (Neuroendocrine Tumours)===

===Cholangiocellular Tumours ===

* Usually occur in younger animals compared with other primary hepatobiliary tumours.

Cholangiocellular tumours include bile duct '''carcinomas''' and '''adenomas'''.  Bile duct carcinomas are the most common malignant hepatobillary tumours in cats and the second most frequent in dogs, with female animals possibly being predisposed. Intra-hepatic carcinomas are more frequent in dogs but in cats, it is unclear whether extra-hepatic masses occur more frequently or whether intra- and extra-hepatic masses occur with equal frequency.

* Primary tumours are aggressive and often affect more than one liver lobe and metastasise most frequently to the regional lymph nodes, the lungs and peritoneum.  

===Sarcomas ([[Haemangiosarcoma|Haemangiosarcoma]] (HSA), Leiomyosarcoma, Fibrosarcoma)===

Bile duct carcinomas are aggressive and they often metastasise to distant sites.  In dogs, these metastases are most common in the regional lymph nodes and lungs but diffuse intra-peritoneal metastasis and carcinomatosis are more common in cats.  Bile duct adenomas (also known as biliary or hepatobiliary cystadenomas) are common in cats, particularly in males.  These tumours are generally insignificant unless they of sufficient size to compress surrounding soft tissue structures and cause [[Biliary Tract - Obstruction|biliary tract obstruction]].

* HSA is the most common hepatic sarcoma in cats

* Leiomyosarcoma is the most common hepatic sarcoma in dogs

* These tumours are aggressive and metastasis to the spleen and lungs is frequently observed.

==Diagnosis==

==Diagnosis==

*Mild '''non-regenerative anaemia''' of unknown cause.  The anaemia may be caused by anaemia of chronic disease, inflammation, red blood cell sequestration and iron deficiency may play roles

*Mild '''non-regenerative anaemia''' of unknown cause.  The anaemia may be caused by anaemia of chronic disease, inflammation, red blood cell sequestration and iron deficiency may play roles

*'''Leucocytosis''' resulting from the associated inflammation and necrosis that can occur with large liver masses.

*'''Leucocytosis''' resulting from the associated inflammation and necrosis that can occur with large liver masses.

*'''Thrombocytosis''', of which potential causes include production of thrombopoietin as a parneoplastic syndrome, iron deficiency, inflammatory cytokines and anaemia.

*'''Thrombocytosis''', of which potential causes include production of thrombopoietin as a paraneoplastic syndrome, iron deficiency, production of inflammatory cytokines and presence of concurrent anaemia.

*Elevation in the blood levels of '''hepatic enzymes''' probably occurs due to hepatocellular damage or biliary stasis.  The extent of the elevation is not proportional to severity of liver damage.

*Elevation in the blood levels of '''hepatic enzymes''' probably occurs due to hepatocellular damage or biliary stasis.  The extent of the elevation is not proportional to severity of liver damage.

*'''[[Hypoalbuminaemia]]''' due to reduced hepatic synthesis of albumin.

*'''[[Hypoalbuminaemia]]''' due to reduced hepatic synthesis of albumin.

====Ultrasonography====

====Ultrasonography====

An abdominal ultrasound scan is advised to evaluate the condition of structures surrounding the liver. It also allows classification of the mass as massive, nodular or diffuse. Doppler techniques can be utilised to assess the vascular structure of tumours and guided fine-needle aspirates or core biopsies can be taken at this time, although it is desirable to await the results of a coagulation profile before undertaking this procedure.  

An abdominal ultrasound scan is advised to evaluate the condition of structures surrounding the liver. It also allows classification of the mass as massive, nodular or diffuse. Doppler techniques can be utilised to assess the vascular structure of tumours and guided fine-needle aspirates or core biopsies can be taken at this time, although it is desirable to await the results of a coagulation profile before undertaking this procedure.  It is traditionally stated that hepatic lymphoma produces a hyperechoic texture on an ultrasound scan.  

====Advanced Imaging====

====Advanced Imaging====

===Other Tests===

===Other Tests===

Cytological examination of ascitic fluid may reveal the presence of neoplastic cells. Effusions are usually [[Modified Transudates|modified transudates]] but [[Haemorrhagic Effusion|haemorrhage]] may indicate the the tumour has ruptured.

Cytological examination of ascitic fluid may reveal the presence of neoplastic cells. Effusions are usually [[Modified Transudates|modified transudates]] but [[Haemorrhagic Effusion|haemorrhage]] may indicate that the tumour has ruptured.

==Treatment==

==Treatment==

===Surgery===

===Surgery===

Surgical excision is advised for hepatic adenomas, bile duct adenomas and massive [[Carcinoma#Hepatocytic|hepatocellular carcinomas]]. Nodulectomy or lobectomy can be used for focal tumours involving only one or a small number of lobes. Diffuse tumours and widespread nodular disease carry a poorer prognosis.

Surgical excision is advised for hepatic adenomas, bile duct adenomas and massive [[Carcinoma#Hepatocytic|hepatocellular carcinomas]]. Nodulectomy or lobectomy can be used for focal tumours involving only one or a small number of lobes. Diffuse tumours and widespread nodular disease carry a poorer prognosis and they have frequently metastasised by the time they are diagnosed.

===Chemotherapy===

===Chemotherapy===