Spleen

Question 1

Shape of spleen: HORSE

Answer 1

Wedge

Question 2

Shape of spleen: RUMINANTS

Answer 2

Flat, oval

Question 3

Shape of spleen: PIG

Answer 3

Triangular on cross section

Question 4

Shape of spleen: DOG

Answer 4

Boot-shaped

Question 5

Shape of spleen: CAT

Answer 5

Long & flat

Question 6

Shape of spleen: BIRD

Answer 6

Small & round

Question 7

Normal histology of CAPSULE & TRABECULAE

Answer 7

• Collagen
• Elastic fibers
• Smooth muscle

Question 8

Normal Histology of WHITE PULP

Answer 8

• Periarterial lymphoid sheath (PALS)
  
  • (T lymphocytes)
  • around the central artery or arterioles
• lymphoid follicles
  
  • (B lymphocytes)
  • surrounded by marginal zone (dendritic cells, macrophages, B, T)

Question 9

Normal Histology of RED PULP

Answer 9

-Venous sinusoids separated by cords of reticular cells with macrophages

Question 10

What is the major fx of Red pulp?

Answer 10

Phagocytosis

Question 11

What is the major fx of White pulp?

Answer 11

Immune

Question 12

Functions of the spleen

Answer 12

1. Blood storage
2. Blood formation –EMH
3. Hb breakdown –Storage of iron
4. Blood filtration (abnormal blood cells/ particulate matter)
5. Initiation of immune response (Ab production, Cell mediated immunity)

Question 13

Causes of Ruptured spleen

Answer 13

1. HBC
2. Hemangiosarcoma
3. Splenomegaly

Question 14

Sequelae of Ruptured spleen

Answer 14

1. Exanguination
2. Scarring
3. Splenic fragments
4. Splenosis

Question 15

What is Splenosis?

Answer 15

–

Question 16

Species commonly associated with Splenic Torsion

Answer 16

Dogs with GDV

Pigs

Question 17

In what species does splenic duplication occur?

Answer 17

Pigs

-incidental finding

Question 18

Features of Sidero-fibrosis (Siderotic plaque)

Answer 18

aka Gandy Gamma bodies

• Aged dogs
• Yellow thickened elevated area on capsule
• Hemosiderosis w/ fibrosis of capsule

Question 19

Mechanism of Amyloidosis

Answer 19

1. Monoclonal Plasma cell proliferation (myeloma)
   - -> fragments of Ig –> increased AL production
2. Chronic inflammation (ex. TB)
   - -> increased serum AA proteins (acute phase proteins) –> production of AA

Question 20

Features of Amyloidosis

Answer 20

• prominent white pulp

- Pale homogenous deposits w/in follicles

Question 21

What stains help ID amyloid?

Answer 21

Grossly –Lugoi’s Iodine –> Deep brown

Microscopic –Congo Red –> deep orange red

Question 22

Causes of Splenic Lymphoid Necrosis

Answer 22

1. Stress (cortisol = toxic to Tcells)
2. Viral infection (immunosuppressive)
3. Septicemia/toxemia
4. Mycotoxicosis

Question 23

Microscopic appearance of Lymphoid Necrosis

Answer 23

“starry-sky” appearance

-Lymphocyto-lysis

Question 24

Causes of Hemosiderosis

Answer 24

1. Aging
2. Hemolytic anemia
3. Anemia of chronic Dz

Question 25

Appearance of Hemosiderosis

Answer 25

Gross: Brown to Black spleen Microscopic: Golden-brown hemosiderin-laden Mphage

Question 26

Pathogenesis of hemosiderosis

Answer 26

RBC lysis --> Iron / globulin / biliverdin --> Iron binds APOFERRITIN--> becomes Ferritin molecule --> ferritin molecules aggregate = Hemosiderin

Question 27

Acute splenic congestion (appearance / cause)

Answer 27

- Reddish-black to purple - Swollen w/ blood Causes: - Shock - Barbiturates

Question 28

Causes of Splenic Thrombosis, embolism, infarct

Answer 28

1. 2ndary to endocarditis 2. Endothelial damage - Septicemia - Hog Cholera 3. Thrombotic dz - IMHA - Purpura hemorrhagica - Acute pancreatic necrosis

Question 29

Types of Acute Splenitis

Answer 29

1. Hemorrhagic splenitis 2. Suppurative splenitis 3. Necrotizing splenitis

Question 30

Hemorrhagic splenitis (Appearance / causes)

Answer 30

aka Blackberry jam spleen -Swollen Bloody Soft Causes: - Anthrax - Erysipela Septicemia - Hog cholera Viremia

Question 31

Suppurative Splenitis (Appearance / causes)

Answer 31

- Swollen or nodular, Dull yellow - Neutrophil infiltration Causes: - Strep. suis Septicemia - Acanobacterium pyogenes - Hardware Dz

Question 32

Necrotizing Splenitis (Appearance / causes)

Answer 32

Multifocal white foci, irregular mottled areas Causes: - Immunosuppressive viruses - Septicemia/ toxemia - Toxoplasma gondii

Question 33

Acute to subacute inflammation

Answer 33

Hyperplastic splenitis--Monocyte-Macrophage hyperplasia - Swollen, Red, Slightly firm - meaty consistency, bulge on cut surface Cause: -subacute septicemia --Salmonella

Question 34

Types of Chronic Splenitis

Answer 34

1. Chronic suppurative splenitis | 2. Chronic granulomatous splenitis

Question 35

Chronic suppurative splenitis

Answer 35

-walled off abscess Causes: - Caseous Lymphadenitis (sheep/goat) - local extension from traumatic reticuloperitonitis

Question 36

Chronic Granulomatous splenitis

Answer 36

Multifocal mottled firm nodules OR Diffusely swollen and firm -necrotic center surrounded by Mphage, epitheliod cells, multinucleate giant cells, lymphocytes, plasma cells, fibrosis Causes: - Mycobacterium (TB) - Tularemia - Mycosis - Toxoplasma

Question 37

Causes of Atrophic spleen

Answer 37

1. Aging 2. Cachexia 3. Stress 4. Viral infection 5. Septicemia/toxemia -lymphoid depletion Thick wrinkled capsule

Question 38

Ddx for Nodular hyperplasia

Answer 38

1. Neoplasia -Lymphoma, leukemia, mets) 2. Chronic Abscess 3. Granuloma 4. Hematoma 5. Lymphoid Hyperplasia

Question 39

Neoplastic Dz

Answer 39

1. Lymphoma 2. Hemangioma/sarcoma 3. Leiomyoma/sarcoma 4. Metastatic neoplasia

Question 40

Lymphoma

Answer 40

Nodular OR diffuse enlargemnt Involving LN, Spleen, marrow, other tissue

Question 41

Hemangiosarcoma (appearance/ common sites/ clinical signs)

Answer 41

Dark red mass Common sites: Right atrium, spleen Clinical signs: - Splenic rupture - intra-abdominal hemorrhage - sudden death