Canine Lymphoma Flashcards
How are lymphomas classified? (4)
- based on anatomic form e.g. gastrointestinal, mediastinal, cutaneous
- cytologic/ histologic criteria
- immunophenotype (b cell or t cell)
- high grade vs low grade
Which lymphoma is the most common?
Multicentric (multiple origins)
Why do high grade lymphomas generally respond better to chemotherapy than low grade lymphomas?
because chemo targets rapidly dividing cells which is what high grade lymphomas are made up of (large lymphocytes= immature= rapidly dividing)
BUT low grade lymphomas still have a better prognosis
What is the major presenting sign for lymphoma?
Peripheral lymph node enlargement e.g. submandibular, prescapular, popliteal with possible hepatosplenomegaly
Why does a lymphoma often cause Polyuria/ Polydipsia?
Lymphoma releases parathyroid releasing hormone which causes hypercalcaemia
Which lymphoma (B or T cell) tends to be the most aggressive?
T cell
What do we mean by ‘Minimum Database’?
Acquired from patient to get a general idea into their health- this includes haematology (including blood smear), biochemistry and urinalysis
What will provide a definitive diagnosis for haematopoietic neoplasia and what will this look like?
Fine needle aspirate cytology of the lymph node or mass
Should see, very few small lymphocytes and a monotonous population of large lymphocytes and possibly some mitotic figures
What lymph nodes should we avoid taking cytology from and why?
Submandibular lymph nodes- they’re very reactive and so can distort figures/ samples
If the initial cytology/ FNA isn’t diagnostic what is our next option?
Biopsy of the lymph node (popliteal is the easiest to do)
What is the benefit of performing an immunohistochemistry of a tissue sample?
allows immunophenotyping- can see if its a b cell or t cell tumour
How does immunocytochemistry differ from immunohistochemistry?
allows immunophenotyping from the cytology slides (so less invasive)
What is PARR and how does it work?
PCR for Antigen Receptor Rearrangements
Uses PCR to evaluate lymphocyte receptor gene length to assess clonality levels
When is it useful to use PARR as oppose to cytology?
Useful when cytology cannot determine neoplastic vs reactive population
In PARR, a polyclonal result suggests….
What about a monoclonal result…
polyclonal= reactive
monoclonal= lymphoma