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More common compared with oesophageal neoplasia but still uncommon accounting for less than 1% of all malignancies. Malignant tumours include:

More frequent compared with oesophageal neoplasia but still uncommon accounting for less than 1% of all malignancies. Malignant tumours include:

* [[Stomach and Abomasum Proliferative - Pathology #Adenocarcinoma|Adenocarcinoma]] - 70-80% of cancers of the somach in dogs

* [[Stomach and Abomasum Proliferative - Pathology #Adenocarcinoma|Adenocarcinoma]] - 70-80% of all canine gastric neoplasms

* [[Stomach and Abomasum Proliferative - Pathology #Squamous cell carcinoma|Squamous Cell Carcinoma]]

* [[Stomach and Abomasum Proliferative - Pathology #Squamous cell carcinoma|Squamous Cell Carcinoma]]

* [[Stomach and Abomasum Proliferative - Pathology #Lymphoma|Lymphoma]] - the most common gastric neoplasm in the cat

* [[Stomach and Abomasum Proliferative - Pathology #Lymphoma|Lymphoma]] - the most common feline gastric neoplasm

* Fribrosarcoma  

* Fribrosarcoma  

* Plasmacytoma

* Plasmacytoma

==Signalment==

==Signalment==

* Male dogs are more commonly affected than female: e.g male:female ratio in those with carcinoma 2.5:1  

* Male dogs are more commonly affected than female: e.g male:female ratio in those with carcinoma 2.5:1  

* Mean age of dogs with carinoma - 8 years

* Mean age of dogs with carinomas - 8 years

* Cats with carcinoma - usually over 10 years

* Cats with carcinomas - usually over 10 years

* Mean age of dogs with benign tumour - 15 years

* Mean age of dogs with benign tumours - 15 years

==Description==  

==Description==  

Aetiology largely idiopathic though long term ingestion of dietary carcinogens may have some responsibility. Long term administration of nitrosamines may cause carcinomas in dogs. In humans, the bacterium ''Helicobacter pylori'' can induce gastric carcinoma and lymphoma. Its role in gastric tumours in dogs and cats has not yet been fully established though it can cause gastritis and ulceration. Belgian Shepher dogs may have a genetic predisposition to gastric carcinoma. Cats with gastric lymphoma are not usually FeLV positive.

Aetiology largely idiopathic though long term ingestion of dietary carcinogens may have some responsibility. Long term administration of nitrosamines may also cause carcinomas in dogs. In humans, ''Helicobacter pylori'' can induce gastric carcinomas and lymphomas. Its role in gastric tumours in dogs and cats has not yet been fully established though it is known to cause gastritis and ulceration. Belgian Shepherd dogs may have a genetic predisposition to gastric carcinomas. Cats with gastric lymphomas are not usually FeLV positive.

Adenocarcinomas: frequently metastasise to the regional lymph nodes (gastroduodenal and splenic lymph nodes), also the liver and sometimes the lungs. They are also locally aggressive and can cause stomach wall perforation and peritonitis. Other complications include:

Adenocarcinomas: frequently metastasise to the regional lymph nodes (gastroduodenal and splenic lymph nodes), also the liver and sometimes the lungs. They are also locally aggressive and can cause stomach wall perforation resulting in peritonitis. Other complications include:

* Pyloric outflow obstruction

* Pyloric outflow obstruction

* Ischaemic necrosis - tumour plugs and develop in the surrounding vasculature

* Ischaemic necrosis - where tumour plugs develop in the surrounding vasculature

Leiomyosarcomas: rarely metastasise.  

Leiomyosarcomas: rarely metastasise.  

Lymphoma: may be limited to the stomach or may affect lymph nodes and other abdominal organs or may be multicentric.  

Lymphoma: may be limited to the stomach, may affect lymph nodes and other abdominal organs or may be multicentric.  

Plasmacytoma: frequently metastases are evident in local lymph nodes.

Plasmacytoma: metastasis is frequently evident in local lymph nodes.

==Diagnosis==  

==Diagnosis==  

===History and Clinical Signs===

===History and Clinical Signs===

* May ne mild or non-specific early on in the disease process

* May be mild or non-specific early on in the disease process

* Chronic vomiting - blood tinged/'coffee grounds' appearance (partially digested blood)

* Chronic vomiting - blood tinged/'coffee grounds' appearance (partially digested blood)

* Weight loss

* Weight loss

* Electrolyte disturbances - secondary to vomiting

* Electrolyte disturbances - secondary to vomiting

* Elevated BUN and creatinine - due to dehydration

* Elevated BUN and creatinine - due to dehydration

* Elevated hepatic enzymes - if hepatic metastasis has occured or if there is resulting obstruction to the common bile duct.

* Elevated hepatic enzymes - if hepatic metastasis has occured or if there is obstruction to the common bile duct.

===Positive Contrast Radiography===

===Positive Contrast Radiography===

* Loss of rugal folds

* Loss of rugal folds

===Ultrasonography===

===Ultrasonography and Biopsy===

Characteristic features of gastric neoplasia are a thickened gastric wall along with disruption of the wall layers. Enlarged lymph nodes may be observed. The rest of the abdominal organs should be checked for metastases. Ulceration appears as a focal outpouching of the luminal (inner) surface with trapped gas bubbles. guided fine-neelde or core biopsies may be taken at this time.

Characteristic features of gastric neoplasia are a thickened gastric wall along with disruption of the wall layers. Enlarged lymph nodes may be observed. The rest of the abdominal organs should be checked for metastases. Ulceration appears as a localised outpouching of the luminal (inner) surface with trapped gas bubbles. Definitive diagnosis requires histopathology of samples. Guided fine-needle or core biopsies may be taken at this time.

===Endoscopy and Biopsy===

===Endoscopy and Biopsy===

This allows direct visualisation of the lesion. Definitive diagnosis requires histolpathology. Several biopsies can be taken via grab biopsy, however the samples may be unrepresentative.  

This allows direct visualisation of the lesion. Several biopsies can be taken via grab biopsy, however the samples may be unrepresentative.  

===Surgical Biopsy===

===Surgical Biopsy===

Alternatively, biopsies can be taken via gastrotomy at the time of surgical treatment (see below). If a GIST is susptected a CD117 immunohistochemical stain can be used for diagnosis.

Alternatively, biopsies can be taken via gastrotomy at the time of surgical treatment (see below). If a GIST is susptected a CD117 immunohistochemical stain can be used for diagnosis (in half of all dogs affected GIST tumours express CD117 (c-kit), a tyrosine kinase receptor).

===Paraneoplastic Syndromes===

===Paraneoplastic Syndromes===

==Treatment==

==Treatment==

===Surgery===

===Surgery===

Prior to any surgical intervention thoracic radiography should be performed for evidence of metastasis. Regional lymph nodes should also be examined along with the rest of the abdominal cavity. For tumours that have not metastasised, resection is the treatment of choice (wide partial gastrectomy or antrectomy with gastroduodenostomy (Billroth 1). However, there are often difficulties as tumours are often in an advanced stage on time of presentation. Excision with large margins whilst maintaining the ability to sucessfully reconstruct the stomach without post-operative complications can be problematic. Futhermore, pylorectomy and gastroduodenostomy or gastrojejunostomy for antral tumours risk iatrogenic injury to the local blood supply as well as the pancreas and extrahepatic biliary system. Post-operative complications are more frequent with resections associated with the pylorus. Neoplasia associated with the lesser curvature is generally unresectable.

Prior to any surgical intervention thoracic radiography should be performed for evidence of metastasis. Regional lymph nodes should also be examined at the start of surgery along with the rest of the abdominal cavity. For tumours that have not metastasised, resection is the treatment of choice (wide partial gastrectomy or antrectomy with gastroduodenostomy (Billroth 1). However, frequently there are difficulties as tumours are often in an advanced stage on time of presentation. Excision with large margins whilst maintaining the ability to sucessfully reconstruct the stomach without post-operative complications can be problematic. Futhermore, pylorectomy and gastroduodenostomy or gastrojejunostomy for antral tumours risk iatrogenic injury to the local blood supply as well as the pancreas and extrahepatic biliary system. Post-operative complications are more frequent with resections associated with the pylorus. Neoplasia associated with the lesser curvature is generally unresectable.

===Chemotherapy===

===Chemotherapy===

===Other Medical Management===

===Other Medical Management===

Symptomatic therapy of for example vomiting may improve quality of life in the short term - treatment options include anti-emetics such as metocolpramide and H2 blockers including ranitidine and cimetidine. Inhibitors of c-Kit e.g imatinib have been used in humans with GIST tumours. Such inhibitors may be useful for GIST in animals.  

Symptomatic therapy of for example vomiting may improve quality of life in the short term. Treatment options include anti-emetics such as metocolpramide and H2 blockers including ranitidine and cimetidine. Inhibitors of c-Kit e.g imatinib have been used in humans with GIST tumours. Such inhibitors may be useful for GIST in animals.  

==Prognosis==

==Prognosis==