[B] 1.82 Hemolymphatic tumors in mammals

Question 1

Haemolymphatic tumours

Answer 1

Neoplasm of leukocytes

• Malignant lymphomas
• Leukemias and myeloproliferative disease
• Plasmacytic tumours
• Histiocytosis

Question 2

Lymphoid tumours: In lymphoid tissues

Answer 2

• B-cell lymphomas
• T-cell lymphomas
• Putative NK-cell lymphoma

Question 3

Lymphoid tumours: Bone marrow/spleen

Answer 3

Leukemias

Question 4

Myeloid leukaemias: Differentiation

Answer 4

• Cytology
• Histopathology
• IHC
• Flow cytometry
• PARR

Question 5

Lymphoid tumour classification

Answer 5

Morphology and biological properties are similar to that of normal hematopoietic cells → Difficult to classify

​Criteria:

• Cell morphology
• Immunophenotype
• Genotype
• Behaviour of tumour

Question 6

Histopathologic classification of lymphoid tumours

Answer 6

• Tissue structure: Follicular or diffuse
• Cytologic morphology of cells
• Immunophenotyping
• B-cell markers
• T-cell markers
• Supplementary antibodies

Question 7

Cytologic morphology of cells used to identify lymphatic tumours

Answer 7

• Nuclear size
• Nuclear shape (Indented/ not indented)
• Chromatin: Mature, heterochromatic

Question 8

Role of viral oncogenesis in haemolymphatic tumours

Answer 8

• Bovine leukosis virus (BLV)
• Feline leukemia virus (FLV)

Question 9

Bovine leukosis virus

Answer 9

• Adult cattle’s enzootic lymphoid leukosis (EBL)
• Sporadic, non-virus induced:
  
  • Calves’ Lymphoid leukosis/juvenile form
  • Thymic form
  • Cattle’s cutaneous lymphoma

Question 10

Enzootic lymphoid leukosis (EBL)

Answer 10

• Via secretions/blood
• Lifelong carriers
• Notifiable disease
• Usually multicentric

Question 11

Feline leukemia virus

Answer 11

• Progressive infection
• Oncogenesis mostly in young age
• Transmission by secretions
• Lifelong carriers

Question 12

Lymphomas in dogs

Answer 12

• 3rd most common type of tumours in the species
• Most of them are multicentric

Question 13

Leukemias

Answer 13

• Malignant tumours of haematopoietic stem cells in the BM
• Neoplastic cells often reach the circulation & infiltrate other organs (spleen liver)
• Differentiation from lymphomas:
  
  • Parallel BM evaluation is needed
• Pancytopenia can follow → Fever, anaemia, bleeding

Question 14

Leukemias: Classification

Answer 14

• Acute leukaemias: Immature blast cells
• Chronic leukaemias: Well-differentiated leukocytes
• Lymphoid leukaemia
• Myeloid leukemia (BM)

Question 15

Plasmacytic tumours

Answer 15

• Plasmacytoma
• Myeloma

Question 16

Plasmacytoma (differentiated B-cell tumour)

Answer 16

• Most frequent type of differentiated B-cell tumour in dogs
• Mostly in soft tissues - Oral cavity, subcut., organs
• Rare in lymph nodes
• Usually solitary & benign

Question 17

Myeloma

Answer 17

• Monoclonal malignant plasmacytic neoplasm
• BM origin
• Multiplex osteolysis & monoclonal gammopathy
• Dogs & cats

Question 18

Histiocytic disease

Answer 18

• Dendritic cell/macrophage origin
• Immunophenotyping is required to differentiate
• Higher incidence in dogs

Question 19

Histiocytic diseases in dogs

Answer 19

• Cutaneuous histiocytoma
• Cutaneous reactive histiocytosis
• Systemic histiocytosis
• Histiocytic sarcoma

Question 20

Cutaneous histiocytoma

Answer 20

• Benign, usually solitary
• Spontaneous regression can occur
• Young dogs
• Complete resection → Cure
• Can look aggressive
• “Top-heavy” appearance

Question 21

Histiocytic sarcoma

Answer 21

• Can be localised or disseminated
• Malignant
• Breed disposition
  
  • Bernese mountain dog
  • Labrador
  • Golden retriever
  • Rottweiler