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:'''Time scale''' - Acute or Chronic
 
:'''Time scale''' - Acute or Chronic
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Order of '''prevalence''' in UK is cats, dogs, cattle, pigs and sheep. In the cat and ox, viral agents have been identified as the causal agents.  
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'''Prevalence'''
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Order of prevalence in UK: cats, dogs, cattle, pigs and sheep. In the cat and ox, viral agents have been identified as the causal agents.
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* FeLV is an important cause of lymphoma in the cat.
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** 70% of cats with lymphoma will test positive for FeLV.
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** FeLV also causes a number of non-neoplastic diseases.
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*** Anaemia.
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*** Leukopaenia.
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*** Thymic atrophy. 
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* Cattle suffer both lymphosarcoma and leukosis in a variety of cytological forms.
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** Bovine lymphoma is caused by [[Bovine Leukaemia Virus]] (BLV).
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*** A retrovirus.
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*** There is a juvenile form of bovine lymphoma seen in young cattle which is not associated with BLV.
    
===Dog===
 
===Dog===
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===Cat===
 
===Cat===
[[FeLV]] is an important cause of lymphoma in the cat. Following the introduction of widespread [[Feline Leukaemia Virus|FeLV]] testing and [[vaccines|vaccination]] the most common type of lymphoma affecting cats is '''alimentary''' when previously it had been mediastinal and multicentric forms.
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In cats following the introduction of widespread [[Feline Leukaemia Virus|FeLV]] testing and [[vaccines|vaccination]] the most common type of lymphoma affecting cats is '''alimentary''' when previously it had been mediastinal and multicentric forms.
Only 10% of lymphoma cases in cats are now associated with FeLV, whereas it used to be 70%.
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Only 10% of lymphoma cases in cats are now associated with FeLV.
 
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The alimentary form affects the mesenteric lymph nodes, intestine, [[Liver - Anatomy & Physiology|liver]], spleen , and potentially the kidney. The thymic form presents as a thymic mass, also in the mediastinal lymph nodes. The pleural lymph nodes and the liver may potentially be affected. Multicentric form is found in the peripheral and deep lymph nodes, liver and spleen. The kidney may sometimes be affected. There is also a renal form affecting kidneys and other abdominal organs and leukaemic form affecting the bone marrow alone, this form is rare.
      
===Horse===
 
===Horse===
In horses, lymphoma is the most common haemopoietic neoplasm. It has been characterised into four main forms: '''alimentary, cutaneous, mediastinal and multicentric''', however, it takes mainly the alimentary form.
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In horses, lymphoma is the most common haemopoietic neoplasm. It has been characterised into four main forms: '''alimentary, cutaneous, mediastinal and multicentric'''.
    
===Cattle===
 
===Cattle===
Cattle suffer both lymphosarcoma and leukosis in a variety of cytological forms. Bovine lymphoma is caused by [[Bovine Leukaemia Virus]] (BLV). There is a [[Sporadic Bovine Leukosis|juvenile form of bovine lymphoma]] seen in young cattle which is not associated with BLV.
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See [[Bovine Leukaemia Virus]].
 
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===Pig===
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Porcine disease is mainly multicentric affecting lymph nodes, liver and spleen.
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===Sheep===
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Ovine lymphoma is uncommon. It may be multicentric or thymic.
      
==Signalment==
 
==Signalment==
 
===Dog===
 
===Dog===
Affected dogs have a wide age range, most are middle-aged however young animals can be affected, 80% of cases affect the 5 to 11 year old age group. There may also be a male predilection.
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Affected dogs have a wide age range, most are middle-aged however young  
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animals can be affected. There may also be a male predilection.
    
===Cat===
 
===Cat===
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===Horse===
 
===Horse===
A '''thoracic effusion''' may occur in the alimentary and multicentric forms of the disease, which usually has the characteristics of a '''[[Modified Transudate|modified transudate]]'''.
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A '''thoracic effusion''' may occur in the alimentary and multicentric forms of the disease, which usually has the characteristics of a '''[[Modified Transudate|modified transudate]]'''. Mediastinal lymphoma also produces clinical signs such as pointing of the forelimb, tachycardia, distension of the jugular vein and caudal displacement of the heart - it may be confused with colic. It should be differentiated from mediastinal abscessation by ultrasound of the mass and cytology of pleural fluid. Intra-abdominal neoplasia (which can be multicentric or alimentary) may presents with a history of chronic weight loss and inappetance, recurring colic and intermittant pyrexia.  
    
==Physical Examination==
 
==Physical Examination==
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'''Horse'''
 
'''Horse'''
:In equine lymphoma, neoplastic cells are not always present, but when they are this may allow diagnosis.
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:In equine lymphoma, neoplastic cells are not always present, but when they are this may allow diagnosis.
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A sample of pleural or peritoneal fluid may be sampled and examined cytologically if it is present. Otherwise a direct fine needle aspirate of the mass of lymph nodes may be performed.
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Any fluid sampled should be a modified transudate and contain a mixed cell population. Neoplastic lymphocytes are pleomorphic round cells that demonstrate anisocytosis and anisokaryosis and have very basophilic cytoplasm. If these cells are present then the diagnosis of lymphoma can be confirmed, otherwise surgical biopsy may be necessary.
    
===Biopsy===
 
===Biopsy===
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==References==
 
==References==
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Copas, V (2011) '''Diagnosis and treatment of equine pleuropneumonia''' ''In Practice 2011 33: 155-16''
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Cowell, R. (2002) '''Diagnostic cytology and haematology of the horse''' ''Elsevier Health Sciences''
 
Cowell, R. (2002) '''Diagnostic cytology and haematology of the horse''' ''Elsevier Health Sciences''
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Head K. W, Else R. W, Dubielzig R.R, (2002)''' Tumours of the Alimentary Tract, in Tumours in Domestic Animals''', 4th edition, Ed Menten D. J, Iowa State Press, ''Blackwell Publishing'', Iowa, pp 471-472
 
Head K. W, Else R. W, Dubielzig R.R, (2002)''' Tumours of the Alimentary Tract, in Tumours in Domestic Animals''', 4th edition, Ed Menten D. J, Iowa State Press, ''Blackwell Publishing'', Iowa, pp 471-472
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Hewetson, M (2006) '''Investigation of false colic in the horse''' ''In Practice 2006 28: 326-33''
    
Morris J, Dobson J (2001) '''Gastrointestinal Tract, in Small Animal Oncology''', ''Blackwell Science'', pp 228-239
 
Morris J, Dobson J (2001) '''Gastrointestinal Tract, in Small Animal Oncology''', ''Blackwell Science'', pp 228-239
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[[Category:Neoplasia]]
 
[[Category:Neoplasia]]
 
[[Category:Splenic Neoplasia]]
 
[[Category:Splenic Neoplasia]]
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=====Species Differences=====
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* The form of the disease may differe between species.
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* '''Feline'''
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** Alimentary.
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*** Affects the mesenteric lymph nodes, intestine, [[Liver - Anatomy & Physiology|liver]], spleen , and potentially the kidney.
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** Thymic
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*** Presents as a thymis mass, also in the mediastinal lymph nodes.
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*** The pleural lymph nodes and the [[Liver - Anatomy & Physiology|liver]] may potentially be affected.
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** Multicentric
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*** Found in the peripheral and deep lymph nodes, [[Liver - Anatomy & Physiology|liver]] and spleen.
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**** The kidney may sometimes be affected.
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** Renal
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*** The kidney and other abdominal organs are affected.
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** Leukaemic
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*** Affects the bone marrow alone.
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*** This form is rare.
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* '''Canine'''
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** Alimentary.
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*** Affects the mesenteric lymph nodes, pancreatic lymph nodes, intestine, and potentially the [[Liver - Anatomy & Physiology|liver]].
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** Thymic.
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*** Thymic and mediastinal masses.
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** Multicentric.
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*** Affects the peripheral and deep lymph nodes, [[Liver - Anatomy & Physiology|liver]], spleen and kidney.
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* '''Bovine'''
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** Thymic.
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*** Mainly affects adults.
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*** Thymic and mediastinal masses.
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*** Some lymph nodes are also affected.
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** Multicentric.
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*** Mainly affects yopung adults.
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*** Affects the peripheral and deep lymph nodes, spleen, [[Liver - Anatomy & Physiology|liver]] and kidney.
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* '''Equine'''
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** Takes mainly an alimentary form.
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** Can rarely be cutaneous.
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* '''Porcine'''
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** Mainly multicentric.
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*** Lymph nodes, [[Liver - Anatomy & Physiology|liver]], spleen.
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* '''Ovine'''
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** Uncommon.
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** May be multicentric or thymic.
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