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Flashcards in Haematopoietic system Deck (72):

 Primary Haematopoietic neoplasia:

Solid vs circulating tumours

solid = discrete mass - lymphoma

Circulating = leukaemia


Define lymphoid leukaemia

Neoplastic lymphocytes in bone marrow/ blood.

ie circulating


Define lymphoma

Neoplastic lymphocytes in tissues/ organs

ie Solid


Name and describe the four classifications of lymphoma.

  1. Anatomical - ie location
  2. Cellular morphology - cell size, nuclear features, mitotic rate
  3. Immuno-phenotype - B/T cell or Null
  4. Biologic behaviour - Low - high grade


True or false.

Low grade tumours are less responsive to chemotherapy than high grade.



Low grade (indolent) tumours are slower growing and therefore less responsive to therapies 


Which immuno-phenotype shows a better response to therapy?

B cell



Generalised, found in multiple lymphocytes.


What are the common featuers of primary bone neoplasia?

  1. Hypercellular marrow: uncontrolled proliferation of the neoplastic haematopoietic cells
  2. Anemia: non-regenerative anemia - ineffective erythropoiesis. Bone marrow is occupied by neoplastic haematopoietic cells = competition for nutrients &/or space (myelophthisis). Neoplastic cells secrete inhib factors
  3. Thrombocytopenia +/- Neutropenia: not always present
  4. Leukemic cells in peripheral blood: immature stages of haematopoietic cells in peripheral blood commonly seen in haematopoietic neoplasia.


What is the difference between lymphoproliferative and myeloproliferative diseases?

Neoplastic transformation of lymphoid cell lines = lymphoproliferative.

Neoplastic proliferation of one or more bone marrow cell lines = myeloproliferative (granulocytes, erythrocytes, monocytes etc)


Describe clinical signs associated with lymphoma.

  1. Non-specific - wt loss and anorexia
  2. Lymphandenopathy - painless swelling
  3. Depending on anatomical location
    1. Exophthalmos - retrobulbar LN
    2. Dyspnoea, tracheal/ oesophageal obstruction - thymic
    3. Diarrhea, obstruction, melena - Alimentary 


Describe the gross appearance of a lymphoma lesion.

  • Lymphnodes - enlarged
    • Soft to firm, bulge on cut surface
    • Pale tan - white
    • Homogenous appearance
    • Focal necrosis/ haemorrhage
    • Fibrosed to surrounding tissue
  • Organomegaly
  • Multiple tan-white-pink organ nodules


Name the most common canine hematopoietic neoplasia.

Canine lymphoma


What percentage of canine lymphoma show multicentric lymphoma?



How does canine lymphoma result in hypercalcemia?

The tumours produce pth-like factor which does not respond to normal negative feedback.

(also occurs in anal-sac carcinomas)


Name the most common malignant neoplasm of cats.

Feline Lymphoma


Which virus is feline lymphoma associated with?


  • 10-20% of cats with lymphoma are FeLV positive
  • Occurs in young cats 
  • Mediastinal and multicentric forms possible 


Which form of feline lymphoma are most common?

Order these as most common onwards..

Misc, multicentric, alimentary, thymic

Alimentary > multicentric > thymic > misc


Which form of lymphoma is characteristic of Enzootic Bovine Lymphoma?

Which virus is associated with the disease?

Multicentric lymphoma of b cells.

Bovine Leukosis virus, retrovirus

Remember: 30% don't initially present with lymphoma - persistent lymphocytosis

3% of cattle develop lymphoma


How is BLV transmitted?

Through transmission of viral infected lymphocytes:

  1. Direct contact
  2. Natural breeding
  3. Contaminated needles
  4. Dehorning/ ear-tagging equipment
  5. Arthropods - horizontal spread


Which sites are commonly affected by Enzootic Bovine lymphoma?


  1. LNs
  2. Right atrium
  3. Abomasum
  4. Spinal canal
  5. Uterus 
  6. Kidney


How is sporadic bovine lymphoma characterised between these different age groups:

  • Calves <6m?
  • Juvenile - yearlings?
  • 2-3 years?

  1. Multicentric lymphoma, symmetrical lymphadenophathy/ leukemia, bone marrow/ organinfiltration
  2. Mediastinal lymphoma - large cranial thoracic/ lower cervical masses - resp distress and wt loss
  3. Plaque-like to nodular raised skin lesions, lesions may come and go, can survive up to 18 months, eventually leads to systemic involvement 


Which groups are most at risk of developing porcine lymphoma?

Where are lesions commonly found?

  1. Females
  2. Large white - autosomal recessive 
  3. <1 yo
  • Multicentric - visceral LN, spleen, liver, stomach, intestine, kidney, bone marrow
  • Mediastinal 


Name and describe three types of plasma cell tumours (benign and malignant)

  1. Plasmacytoma
    1. Cutaneous - common in dogs, surgery is curative - benign
    2. Extramedullary - don't arise from bone marrow, may affect GI tract, may mets to LNs
  2. Plasma cell myeloma - aggressive and malignant tumours arising from bone marrow 


Describe this lesion.

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The pinna of this dog has a 1cmx1cm nodular red mass which protrudes from the surface of the ear. The mass is firm to touch and shows well demarcation.

Pinnal cutaneous plasmacytoma


Describe the histological finding associated with plasmacytomas.


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  1. Sheets of rounds cells 
  2. Show anisocytosis - uneven size
  3. Show anisokaryosis - variation in nuclear size
  4. Clock face pattern of dense chromatin seen
  5. Halo of Golgi
  6. Multinucleated giant cells may be seen


Describe the gross findings associated with multiple myeloma.

  • Affected bone exhibit multiple dark-red soft / gelatinous tissue nodules filling areas of bone resorption / lysis.
  • 2/3 of dog cases show osteolytic lesions
  •  Lesions can be found in any haematopoietically active bone, but are most common in the vertebrae.


True or false.

Histological signs of multiple myeloma are similar to that of plasmacytoma.

Describe the histo changes.


Masses composed of sheets of neoplastic plasma cells in the bone marrow


What clinical signs are commonly associated with plasma cell myeloma?

  • Pain in affected bones - lameness
  • Spinal cord compression leads to paraplegia - pathological ventrebral fracture
  • Hypercalcemia - osteolysis
  • Bence-jones proteinuria
  • Monoclonal gammopathy
  • Hyperviscosity syndrome - increased blood viscosity


Bence-Jones protein

Monoclonal globulin protein/ immunoglobulin light chain found in urine

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Decribe this serum electrophoresis.

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Monoclonal gammopathy



A mononuclear phagocyte


  1. What are the two types of reactive histiocytosis?
  2. True or False - It is not considered a true neoplastic disorder.
  3. What is the cell of origin?
  4. Describe the clinical signs.

  1. Cutaneous - limited to the skin, systemic - affects skin and other organs
  2. True - it is an immunoregulatory disorder - controlled by immunosuppressive therapy
  3. Activated dermal dendritic cell (APC)
  4. Multifocal skin masses which come and go and are progressive


Decribe the histo features of canine reactive histiocytosis.


Lymphocytes and inflammatory cels at the base of the tumour

Regression due to apoptosis of histiocytes


A malignant neoplasia of macrophages or dendritic cells.

Which breed of dog are associated with the disease?


Histiocytic sarcoma

Rottweiler, bernese mountain dog, flat coats



Describe the differences between solitary and multiple lesions which occur in histiocytic sarcomas.

Multiple - disseminated (malignant) - occurs in spleen, lung, LNs, bone marrow, skin, subcutis

Solitary - surround joints, subcutis, liver, lungs or splee, brain


What histological features characterise disseminated histiocytic sarcomas?

Masses/ diffuse infiltrates composed of atypical histiocytes. 

May retain the ability to phagocytose - haemophagocytosis = non-regnerative anaemia 


Why are eosinophils often associated with mast cell tumours?

Which type of stain is used to identify mast cells definitively?

Mast cells secrete granules which secrete eosinophilic chemotactic factor which cause eosinophils to move into the site.

Toluidine blue


Describe the structure and function of the lymphnodes.

Outline the circulation of lymph through the lymphatics.

Structure - Outer cortex contains follicles (mainly b cells), inner cortex (mainly t cells), medulla (mainly b cells and macrophages)

Function - immune response and lymph filtration

Afferent lymphatics -- subscapular sinuses -- trabecular sinuses -- medullary sinuses -- efferent lymphatics -- thoracic duct


What disease situations may lead to enargement of the lymphnodes?

  1. Lymphadenitis
  2. Lymphoid hyperplasia
  3. Hyperplasia of monocyte/ macrophage system
  4. Primary or secondary neoplasia




Enlargement of the lymphnodes due to an unknown cause.



An inflammatory response to an infectious agent within the node


What gross changes are associated with chronic lymphandenitis?

LNs are:

  1. Large
  2. Irregular
  3. Firm - fibrosis
  4. Supprative/ granulomatous inflammation



Describe the gross appearance of chronic suppurative lymphandenitis.

Name two bacteria which can lead to these findings.

Swollen LNs with a puss filled centre (LN abscesses), may fistulate (burst) to the skin surface,

They are a response to pyogenic bacteria such as:

  1. Strep equi var equi (zooepi is also pyogenic)
  2. Strep porcinus - porcine jowl abscesses 


Describe the pathogenesis of bastard strangles.

Which LNs are often affected by strangles?

Inward bursting of LN abscesses leads to swallowing of pus - intestinal spread of bacteria.

Parotid, retropharyngeal, mandibular LNs


Outline the pathogenesis of Porcine Jowl Abscess.

Ingested bacteria colonise oral cavity/ tonsils and spread to mandibular LNs 


The bacteria causes caseous lymphadenitis of the mediastinal LNs.

Corynebacterium pseudotuberculosis


  1. Outline the pathogenesis of Corynebacterium pseudotuberculosis.
  2. How do clinical lesions differ between the main domestic species?

  1. Enters via contamination of shear wounds (rarely inhalation), drains to regional lymphnodes (superficial more affected than deep)
    1. Prescapular/ prefemoral
  2. Species
    1. Sheep/ goat - chronic suppurative lymphandenitis
    2. Horse/ cattle - Ulcerative lymphangitis
    3. Horse - Pectoral abscess 


Describe this lesion

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This lymphnode is diffusely enlarged. The normal architecture is completely disrupted by a lamellar formation of white pus and firm fibrous tissue. 

Chronic diffuse severe suppurative fibrosing lymphandeitis

Corynebacterium pseudotuberculosis


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Focal shearing wound abscessation of the scapular LN.

Corynebacterium pseudotuberculosis


Describe this lesion

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Focal swelling of the mandible of a piglet - could be LN salivary gland or neoplastic?

Skin of the mass shows multifocal to coelescing irregular areas of haemorrhage.

The mass is approximately 20x20 cm

Chronic focal severe suppurative lymphandenitis - Porcine jowl abscess

Streptococcus porcinus


Describe this lesion

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This lymphnode shows multifocal to coelescing areas of disruption of architecture by a white to yellow mass. There is a focal area that is severely affected (2x1cm). The mass is firm to oozing on the cut surface.

Chronic multifocal-coelecing mod-severe granulomatous lymphandenitis

Mycobacterium bovis

(MAP, Actinobacillus lignieresii, parasitic)


Diffuse granulomatous lymphadenitis caun be caused by what?

How do LNs appear grossly?

Enlarged, firm, pale, loss of architecture


Histoplasma capsulatum

Blastomyces dermatitidis

Cryptococcus neoformans


Describe this lesion

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Area of central necrosis surrounded by epitheloid macrophages and fibroblasts (capsule)

Granulomatous lymphandenitis

Mycobacterium bovis


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Acid fast Mycobacterium bacteria stained with Ziel Nielson



Postweaning multisystemic wasting syndrome



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Diffuse enlargement of the mesenteric lymphnodes - PMWS (PCV2)


Botryoid intracytoplasmic viral inclusions are found in what condition?





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Reactive lymphoid hyperplasia

  • Proliferation of lymphoid follicles
  • Increased T cells in paracortex
  • May have increased plasma cells in medullary cords

Caused by: Ag response, Interleukin circulating


What types of tumours commonly metastasise to the lymphnodes?



Mast cell tumours


Describe the three stages used to assess tumour malignancy.

Assessment of regional lymphnodes.

Stage 0 - LN normal

Stage 1 - LN enlarged but freely moveable

Stage 2 - LN enlarged and fixed


What is the function of the thymus?

Proliferation and maturation of T cells


Which two types of neoplasm are possible of the thymus?

Thymic lymphoma - T cell

Thymoma - epithelial


Describe this lesion

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Diffuse enlargement (rounded edges) of the spleen. The tissue appears to be friable with a beige to orange discolouration.

Chronic diffuse moderate lymphoplasmasitic amyloidosis of the spleen



Splenic torsion may be a sequelae to what GIT disorder in the dog?

Splenic torsion


Describe this lesion

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Multifocal to coelescing white round white lesions throughout the splenic tissue. (miliary)

Chronic disseminated severe suppurative hepatitis

Francisella tularensis (Yersinia pseudotuberculosis)


What aetiological agents can cause septicaemic splenitis?



African Swine fever


What aetiological agent causes granulomatous splenitis in the chicken?

Mycobacterium avium


What aetiological agent can cause diffuse granulmatous splenitis in the dog?



Differentials for splenic masses

Benign nodular hyperplasia

Neoplasia - haemangiosarcoma


Lymphoid hyperplasia of the spleen

White pulp


Benign endothelial tumour of the spleen



Describe this lesion

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Multifocal 5x5x5cm nodular masses protruding from the splenic surface, poor demarcation on histology. Firm to touch and beige in colour.

Splenic haemangiosarcoma

Sequelae: splenic rupture, haemoabdomen, peritoneal seeding and metastasis