Lymphoma

Question 1

What does immunophenotyping tell us about alimentary lymphoma

Answer 1

Over 90% of low-grade alimentary lymphoma and large granular lymphocyte lymphoma ae of T cell immunophenotypes, whereas intermediate and high-grade alimentary lymphoma are variably of B or T cell origin

A strong association between immunophenotype and location within the gastrointestinal tract has been identified
- B cell lymphoma predomintes in the stomach and large intestine
- T cell lymphoma is most common in the small intestine

Question 2

Where do T cell lymphoma arise from

Answer 2

T cell lymphomas arise from the diffuse, mucosal-associated lymphoid tissue (MALT) of the small intestine, which includes lamina propria and intraepithelial compartments populated largely by CD3+ T cells

Question 3

What is the suspected origin of large granular lymphocyte lymphoma

Answer 3

LGLLs arise from neoplastic transformation of natural killer cells and cytotoxic T lymphocytes within the intestinal epithelium

Question 4

Where do B cell lymphomas arise from

Answer 4

B cell lymphomas appear to originate principally from organised lymphoid tissues, including Peyer’s patches and mucosal lymphoid nodules, which are concentrated in the distal small intestine, caecum and colon

Gastric B cell lymphomas in cats are proposed to arise from diffuse gastric MALT colonised by Helicobacter heilmannii or from gastric mucosal lymphoid nodules

Question 5

What is the more likely immunophenotype of lymphoma from FeLV antigen-positive cats

Answer 5

Lymphomas from FeLV antigen-positive cats are significantly more likely to be of T cell immunophenotype

Question 6

What are the characteristics of FIV-associated lymphoma

Answer 6

FIV-associated lymphoma is typically:
- extranodal
- high grade
- of B cell phenotype
- including atypical lymphoma (e.g., nasopharyngeal) and mixed lymphoma with involvement of multiple anatomical sites

Question 7

Which hematological finding is associated with large granular lymphocyte lymphoma

Answer 7

In LGLL, marked neutrophilic leukocytosis is usually present, which may be accompanied by a regenerative left shift

A peripheral lymphocytosis (with LGL morphology) is documented in over 80% of cats with LGLL

Question 8

Explain why hypocobalaminemia is frequently seen in cats with LGAL

Answer 8

Up to 80% of cats with LGAL are hypocobalaminemic

Cobalamin is absorbed from the ileum, and the ileum and jejunum are the most common locations for LGAL