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| ====Lymphoid Neoplasms==== | | ====Lymphoid Neoplasms==== |
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− | | + | See [[Lymphoma]] |
− | * '''Lymphoma''', '''malignant lymphoma''' and '''lymphosarcoma''' are different terms for the same condition.
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− | ===== Classification=====
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− | * '''Cytological classification'''.
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− | ** Well differentiaed (lymphocytic)
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− | *** The malignant cells represent normal lymphocytes, although in excessive numbers.
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− | ** Poorly differentiated (lymphoblastic).
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− | *** The malignant cells represent atypical lymphocytic cells with lymphoblastic characteristics.
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− | * '''Tumour distribution'''
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− | ** Nodular/ follicular.
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− | *** A well organised pattern of slow growth.
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− | *** No metastasis.
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− | *** Are of the B-lymphocyte type.
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− | ** Diffuse.
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− | *** Result in effacement of normal lymphoid architecture by a very homogeneous population of lymphoid cells.
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− | * '''Anatomical classification'''
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− | ** Thymic.
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− | ** Only the [[Thymus - Anatomy & Physiology|thymus]].
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− | ** Alimentary.
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− | *** Gut and associated lymphoid tissue.
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− | ** Multicentric.
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− | *** Widespread involvement of lymph nodes.
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− | ** Cutaneous lymphoma.
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− | *** Usually presents as generalised skin disease, but is a malignant transformation of T cells with a propensity for pithelial sites
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− | * '''Type of lymphocyte'''
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− | ** T-cell.
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− | ** B-cell.
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− | ** NK-cell.
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− | * '''Time scale'''
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− | ** Acute.
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− | ** Chronic.
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− | =====Prevalence=====
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− | * Order of prevalence in UK: cats, dogs, cattle, pigs and sheep.
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− | ** In the cat and ox, viral agents have been identified as the causal agents.
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− | * Lymphoma is one of the prevalent neoplasms in the dog.
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− | ** 80% of cases affect the 5 to 11 year old age group.
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− | ** The incidence is about 28 per 100,000 dogs.
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− | ** Blood of affected dogs shows neither a relative nor absolute increase in the number of lymphocytes until the late stages of the disease.
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− | *** When this stage is reached, poorly differentiated cells may appear in the blood.
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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.
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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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| ====Lymphocytic Leukaemia==== | | ====Lymphocytic Leukaemia==== |