Lymphoma Flashcards
What is the difference between lymphoma and leukaemia?
What are the precursors of lymphocytes?
Lymphoma is neoplastic lymphoid cells arising in LNs and/or extra-nodal locations.
Leukaemia is neoplastic hematopoietic cells arising usually in the bone marrow (e.g. myeloid, erythroid, lymphoid).
Lymphoblasts.
- Multicentric lymphoma takes up what % of all cases of lymphoma in dogs?
- Breeds and ages most common in?
- What multicentric mean lymphoma?
- Sites?
- In what other animals is multicentric lymphoma common?
- > 80%
- Boxers, labs etc, 5-11yrs old.
- Affecting more than one site.
Can be T cell or B cell lymphoma. - Frequently widespread in body, in particular spleen and liver are commonly involved.
- Cattle, horses, small ruminants, pigs.
- What type of lymphoma os cutaneous lymphoma?
- Types of cutaneous lymphoma?
- Typically T cell.
- Epitheliotropic – mycosis fungoides / Sezary syndrome. (targets epidermis, MMs, mucocutaneous junctions etc.)
Non-epitheliotropic – appear as a subcutaneous “panniculitis like” T cell lymphoma or anaplastic large T cell lymphoma. (targets subcutis).
- What spp. does mycosis fungoides (CD8+ T-cell) usually affect?
- Time frame and distribution?
- Clinical presentation.
- Older dogs, cats, horses.
- Chronic multifocal.
- Variable – diffuse erythema, scaling, focal hyperpigmentation, plaques, nodules. Initially limited to skin, later –> lymphadenopathy, leukaemia, internal organs affected (Sezary syndrome).
- In what spp. is alimentary (intestinal) lymphoma common?
- Where does alimentary (intestinal) lymphoma originate from?
- Lymphoma type?
- Extent/distribution?
- Clinical presentation.
- Where does it tend to metastasise to?
- Old cats, dogs, horses, pigs.
- at any level of the GIT – segmental or diffuse.
- B cell.
- Can be solitary or multiple nodules - sometime diffuse involvement of an intestinal segment.
- Malabsorption and weight loss.
- Mesenteric LNs and other viscera e.g. liver.
What are the viral aetiology lymphomas?
Feline Leukaemia Virus (FeLV) (Gammaretrovirus).
Bovine Leukaemia Virus (BLV) (Deltaretrovirus)
- What causes the neoplastic change in FeLV?
- What type of lymphoma can FeLV transform into?
- FeLV spread?
- Insertional mutagenesis. – random so not every infected cat will develop lymphoma.
- T cell lymphoblastic lymphoma but possible B cell lymphoma.
- Horizontally among cats.
- How can BLV transform to lymphoma?
- Transmission of BLV?
- What type of lymphoma can BLV transform into?
- Potential development of the disease.
- Virus carries additional genes that encode for regulatory and accessory proteins.
- Horizontally by transfer of infected lymphocytes.
- Diffuse large B cell lymphoma.
- Development of antibodies against viral antigens leads the animal progressively from an asymptomatic stage to lymphocytosis and eventually neoplasia. Lymphocytosis does not occur in all infected animals and only a small percentage of animals will develop tumours. Animals usually between 4 to 8 years.
- In what spp. does Marek’s disease occur?
- What is it caused by?
- Disease type?
- Clinical signs.
- What can be grossly observed?
- What may tumours of MD resemble?
- Birds.
- Herpesvirus.
- Lymphomatous and neuropathic.
- Paralysis of the legs and wings.
- Enlargement of peripheral nerves. Depending on the strain, lymphomatous, neoplastic lesions can occur in multiple organs such as ovary, liver, spleen, kidneys, lungs, proventriculus and skin.
- Tumours induced by retroviral pathogens such as avian leukosis virus and reticuloendotheliosis virus.
How can we differentiate between Marek’s diseases/avian leukosis and reticuloendotheliosis?
Marek’s disease has pleomorphic lymphocyte cells compared to a uniform population of lymphoblasts in reticuloendotheliosis.
- What is sporadic lymphoma (non-BLV)?
- At what age does it affect the animals?
- Calf/juvenile form – usually multicentric. Symmetrical lymphadenopathy and leukaemia.
- Commonly 3m to 6m (may be present at birth).
Basic principles for classifying lymphomas.
anatomical
Multicentric (more than one site).
Solitary (one site).
Thymic.
Alimentary.
Cutaneous.
Basic principles for classifying lymphomas.
Cytological.
- Small to large.
- Well differentiated to anaplastic.
- Cytoplasm (amount, type, N:C ratio).
- Nuclear size shape, chromatin, nucleoli.
- Mitoses.
- The more variety in shape and size, the more likely to be malignant.
**anisocytosis, anisokaryosis, pleomorphic.
Basic principles of classifying lymphomas.
Histological.
- Follicular (nodular) – cells organised in distinctive nodules.
- Diffuse – dense sheet of cells.
Basic principles of classifying lymphomas.
Immunophenotype.
Immunophenotype (what identifying molecules can we see?)
- T or B cells.
- Non-T or non-B (e.g. NK).
- T-cell rich B-cell lymphoma, B-cell rich T-cell lymphoma.
