Pathology of Lymphoid organs

Question 1

Features of reactive lymphoid hyperplasia

Answer 1

Increased germinal centres (=proliferation of B cells) Increased macrophages in the subcapsular sinuses Expanded paracortex (=proliferation of T cells) Plasma cells in the sinuses Increased amount of incoming lymph; moist

Question 2

Lymphoid tissue undergoes hypertrophy? true or false?

Answer 2

false Only hyperplasia

Question 3

Lymphadenitis

Answer 3

inflammation as a result of direct infection

Question 4

What is this lesion?

Answer 4

Ovine - CLA

Ovine caseous lymphoadenitis

Chronic suppurative lymphadenitis

Question 5

What is this disease?

Answer 5

Corynebacterium pseudotuberculosis

Question 6

Cause of this chronic suppurative lymphadenitis?

Answer 6

Porcine Jowl abcess - streptococcus porcinus

Question 7

Features of equine strangles

Answer 7

subacute suppurative lymphadenitit

• enlarged nodes, soft, wet and red.
• On cut surface often bulging and hyperemic. Exudate is usually sero-purulent

Question 8

Cause of Post weaning Wasting syndrome?

type of inflammation?

Answer 8

Porcine circovirus 2

Granulomatous lymphadenitis and lymphoid depletion

Question 9

Secondary lymphadenitis

Answer 9

Bovide tuberculosis - chronic granulomatous lymphadenitis

Wooden toungue - pyogranulomatous lymphadenitis and glossitis

Rhodococcus equi - pyogranulomatous enteritis and lymphadenitis

Johne’s disease - granulomatous enteritis and lymphadenitis

Feline Infectious peritonitis (coronavirus) - granulomatous lymphadenitis

Question 10

Immunophenotype?

B or T cells?

Answer 10

Immunochemistry

PARR (PCR for Antigen receptor rearrangement)

Flow cytometry

Question 11

How does flow cytometry work?

Answer 11

Uses monoclonal antibodies + fluorescent markers. Can get differences in cell size and phenotype

Question 12

Define lymphadenopathy

Answer 12

Lymph node abnormality, commonly used to denote enlargement of unknown cause

Question 13

Causes of lymphoid atrophy/hypoplasia

Answer 13

• Lack of antigenis stimulation
• Cachexia (neoplia, starvation): loss of T cells
• Aging; Increased fibrous tissue, decreased B and T cells

Radiation; lymphocytolysis, can return to normal

Viral infections; viruses targeting lymphoid tissue.

Question 14

Primary infectious diseases of the lymph nodes

Answer 14

• Corynebacterium pseudotuberculosis from open wound -> caseous lymphadenitis
• Streptococcus porcinus (jowl abscess in swine) -> suppurative inflammation (green/yellow, creamy, odourless exudate)
• Streptococcus equi (strangles) -> infection of oral/resp tract -> suppurative lymphadenitis
• Streptococcal lyphadenitis in dogs. Similar to swine.
• Porcine circovirus-2 (Postweaning Multisystemic Wasting Syndrome) -> granulomas

Question 15

Lymphoproliferative diseases

Answer 15

Any neoplastic expansion of lymphoid cells

• lymphoma
• leukaemia
• plasma cell neoplasms

Question 16

Myeloma

Answer 16

plasma cell neoplasm from bone marrow

Question 17

Plasmacytoma

Answer 17

Plasma cell neoplasm arrising outside the bone marrow

Question 18

What is PARR. (PCR for antigen receptor rearrangement) used for?

Answer 18

Used to distinguish reactive lymphoid hyperplasia from lymphoid neoplasia