Pathology of the Hematopoietic System - Part 2 Flashcards
Lymph nodes
* Outer cortex follicles (mostly __ cells)
* Inner cortex paracortex (mostly __ cells)
* Medulla mostly __ cells and _____
B, T, B, macrophages
Lymph nodes
* Function:
- ______ of lymph
- _______ response
* Lymph circulation:
* Afferent lymphatics
→ ______ sinuses
→ _____ sinuses
→ ____ sinuses
→ _____ lymphatics
→ thoracic duct
Filtration, Immune, subcapsular, trabecular, medullary, efferent
Small LN may be indicative of
* Lymphoid ____
* Lymph node _____
* Lymph node _____
atrophy, degeneration, hypoplasia
Enlarged LN may be indicative of
* Lymphoid ______ +/- ______
* _____: bacterial, viral,
fungal, protozoal, foreign body
* _____ neoplasia
* _____ neoplasia
hyperplasia, drainage, Lymphadenitis, Metastatic, Primary
What are the three lymph node reaction patterns?
- Small LN
- Enlarged LN
- Discoloration/Pigment
Lymphoid hyperplasia
* Immunological reaction = response to antigen _______ or circulating ______ levels
* Causes lymph node ______
* Can be _____ or _____
* Lymph nodes draining site of ___ infection or _____
presentation, interleukin, enlargement, localized, generalized, local, vaccination
Lymphoid hyperplasia in a dog
Lymphoid hyperplasia
Suppurative lymphadenitis is usually caused by a ________ infection.
1. List bacterial strains that lead to suppurative lymphadenitis in horses, pigs, sheep, goats, and cattle.
Bacteria
* Streptococcus equi ssp. equi (horse)
* Streptococcus porcinus (pig)
* Corynebacterium pseudotuberculosis (sheep, goat)
* Trueperella pyogenes (cattle, sheep)
Granulomatous lymphadenitis is usually caused by a ________, _______, or ______ infection.
1. List bacterial strains that lead to suppurative lymphadenitis in horses, and ruminants.
2. List viral strains that lead to suppurative lymphadenitis in pigs, and cats.
3. List fungal strains that lead to suppurative lymphadenitis.
bacterial, viral, fungal
1. * Mycobacterium: Mycobacterium bovis, Mycobacterium avium subsp. paratuberculosis
(ruminants)
* Rhodococcus equi (horse)
2. * Porcine circovirus 2
* Feline infectious peritonitis
3. Blastomyces dermatitidis, Cryptococcus neoformans, Histoplasma capsulatum
Equine, retropharyngeal lymph node
* MDx: Suppurative lymphadenitis
* Etiologic agent: Streptococcus equi subsp. equi
* Name the condition: Strangles
Bastard strangles in a horse
- Ovine, lymph node
- MDx: Caseous lymphadenitis
- Etiologic agent: Corynebacterium pseudotuberculosis
“Onion skin” - bottom right
Bovine, mesenteric Lymph node
MDx: Granulomatous lymphadenitis
Etiologic agent: Mycobacterium bovis
Rhodococcus equi
Rhodococcus equi
* A common, facultative ______ gram-_____ bacterium
* Typically in ___ __-__ months old
* Two primary forms of disease,
* Respiratory: ?
* Enteric: ?
intracellular, positive, foals, 1-6, Pyogranulomatous bronchopneumonia, Ulcerative enterocolitis, caseous or granulomatous
lymphadenitis
List the forms of Primary Neoplasia:
Primary neoplasia
* Lymphoma
* Plasma cell tumor
* Histiocytic neoplasms
List the forms of Metastatic neoplasia:
Metastatic neoplasia
* Carcinomas, melanomas, mast
cell tumors, etc.
Metastatic oral melanoma in a dog
- Hemosiderosis: ______ discoloration observed in ____ ____ draining areas of ______.
Brownish, lymph nodes, hemorrhage
- Anthracosis: Relatively common finding in the _______ lymph nodes
of dogs and humans living in ____ _____ areas. Carbon particles are retained in ______, mainly
those located in the _____ cords, so only the ___ appears black.
bronchial, polluted, urban, macrophages, medullary, medulla
Anthracosis in a cow
Describe the structure and function of the red pulp of the spleen.
Describe the structure and function of the white pulp of the spleen.
Diffuse splenomegaly is described as ?
Bloody, Meaty
Nodular, spleen is described as ?
Bloody, Meaty
Diffuse splenomegaly with a bloody
consistency (bloody spleen)
* Congestion
* Torsion
* Barbiturate euthanasia
* Septicemia
* Anthrax
* Acute hemolytic anemia
What is this picture showing?
Barbiturate-induced splenomegaly, (acute passive congestion) in a horse
- bulging appearance
- on histo, all you see is a sea of RBCs b/c organ is congested
- Common cause is barbituate induced
What can be seen in this image?
Marked splenomegaly (cause of acute passive congestion) in a dog with gastrosplenic torsion/volvulus.
- not uncommon to see an enlarged spleen in gastrosplenic torsion.
What can be seen in this image?
Dog, IMHA, Noah’s Arkive. Splenomegaly due to histiocytosis and hemosiderosis (break down product form RBC which accumulate and are engulfed by RBC).
splenogmegaly –> RBC will be phagocytized and brought to the spleen.
What can be seen in this image?
Right: Dog, jaundice, IMHA, AVC
Clinically, your patient will be jaundice due to IMHA.
What can be seen in this image?
Cattle, anthrax. Splenomegaly due to congestion
Cattle with diffuse splenomegaly, think of anthrax.
What can be seen in this image?
Anthrax, bloated carcass. Affected animals develop rapid post-mortem autolysis – blood oozes from body orifices. Do NOT perform autopsy; anthrax is zoonotic and it can kill us. Collect blood that is oozing out —> blood smear –> look for bacili.
In the case of anthrax, should you perform an autopsy?
DON’T perform post-mortem examination of a suspected animal
* Carefully collect a postmortem blood sample from a peripheral
vein (e.g., the jugular vein or ear vein) and examining a blood
smear for the presence of the capsule using a suitable stain
(e.g., M’Fadyean methylene blue stain
What can be seen in this image?
Bacillus anthracis, characteristic red-stained capsule,
methylene blue stain, OVC. B. anthracis is a large
bacillus, forms short chains and is characterized by square ends
and a distinct capsule
Diffuse splenomegaly with a ____ consistency (meaty spleen) b/c composed of ___ not blood.
* Neoplasia
* Prolonged septicemia (remodeling in tissue)
* Chronic hemolytic anemia (acute phase –> jaundice, chronic –> meaty spleen).
* Diffuse granulomatous disease –> Example: Mycobacterium bovis, tuberculosis, Brucella spp., Francisella tularensis, systemic mycoses (e.g. histoplasmosis)
* Diffuse follicular hyperplasia (cannot be differentiated from neoplasia Benign condition; must determine this on histo)
firm, cells
What can be seen in this image?
Splenic lymphoma in a dog
White material ; All neoplastic lymphocytes, which present has white material grossly.
Tularemia is a disease that is…
* Cause: ?
* Present in which species? (“____ fever”)
* Zoonotic or Non-Zoonotic?
* Causes ___ disease in cats; fights _____, and then gets infected. Can also cause _____ disease in humans
* Grossly, what can be seen?
* Perform necropsy under the ______.
Francisella tularensis
wild rodents , rabbit (infect rabbits = death)
Zoonotic
systemic, rabbit, systemic
Multifocal miliary white foci within the spleen, lymph node and liver
Hood
What can be seen here?
Tularemia in a beaver
Not easy to differentiate this from neoplasm
Micro-abscesses are variable in size, unlike neoplasia.
What can be seen here?
Diffuse lymphoid hyperplasia in a dog
Result of spleen encountering antigen (reactive response).
Can also see one large nodule in cases of lymphoid hyperplasia as well.
Nodular spleen with bloody consistency
Examples of Nodules you might see with this case?
- Hematoma
- Hemangiosarcoma (would not see in spleen?)
- Incomplete/irregular contraction
- Acute splenic infarct: As infarcts age (mature/become chronic) they become tan and firm in consistency
- Nodular hyperplasia (diffuse or focal)
What can be seen in this image?
Splenic hematoma, dog
DDx: splenic hematoma vs splenic hemangiosarcoma. Differnetiatian is important; hemangiosarcoma has poor prognois because metastasizes to other parts of the body.
Histopathology is required for differentiation
Splenic hemangiosarcoma
* Most common ____ tumor of the ___ spleen –> ________
What can be seen grossly?
Prognosis? Explain?
malignant, canine, Hemoabdomen, Single to multiple, discrete to coalescing masses, Poor prognosis; often metastasize
What can be seen in this image?
Splenic hemangiosarcoma
Good place to find cells?
Hemangioma/hematoma/hemangiosarcoma = first thoughts when see nodules on spleen
If see metastasizes to lung, = hemangiosarcoma
HISTO = DIAGNOSIS
Classical swine fever is also called?
1. Caused by which virus?
2. What does this virus target?
3. What can be seen grossly?
- Hog cholera
- Targets macrophages, endothelial and epithelial cells (endothelial damage = which is why you see vasculitis)
- hemorrhage in the kidneys (turkey-egg kidney), splenic
infarcts, necrotizing tonsillitis, button ulcers of cecum and colon
Classic swine fever and african swine fever cause similar pathologies
What can be seen in this image?
Acute hemorrhagic infarcts
What can be seen in this image?
Chronic hemorrhagic infarcts
Infarcts healing
What can be seen in this image?
CSF in a pig. Tonsillar necrosis
B/c attacks epithelial cells
What can be seen in this image?
CSF in a pig. Button ulcer
B/c attacks epithelial cell
What can be seen in this image?
African swine fever in a pig. Ecchymosis of kidney
Turkey egg appearance b/c hemorrhage affecting kidney.
In cases of nodular spleen with firm consistency, what are your differentials?
- Focal nodular hyperplasia
- Granuloma; Example: Mycobacterium
- Abscessl; Example: Streptococcus equi subsp. equi, Rhodococcus equi,
Corynebacterium - Neoplasia
- Primary: Lymphoma, Histiocytic sarcoma
- Splenic stromal sarcoma (spindle cell)
- Metastatic
What can be seen in this image?
Nodular hyperplasia of a spleen from a dog
histopathology to determine diagnosis
What can be seen in this image?
Example of multifocal granulomatous splenitis in a turkey caused by Mycobacterium avium
Histiocytic sarcoma is of interstitial ____ cell origin (a type of _____)
1. Which dog breeds are affected/predisposed?
2. How many forms of this exist?
3. What organs are affected?
dendritic, histiocyte
1. Bernese Mountain dogs, Rottweilers, Golden retrievers, Flat-coated retrievers
2. Localized or Disseminated forms
3. Spleen, lung, sometimes just present on the skin, meninges, lymph nodes, bone marrow, and synovium
What can be seen in this image?
Histiocytic sarcoma
on histo see MQ and DC; forms a sheet
Poor prognosis; diagnosis of this condition is important.
What can be seen in this image?
Metastatic carcinoma to the spleen in a dog
Can’t tell if primary or metastatic; need more clinical information
Spleen – Miscellaneous diseases
* Siderotic plaques is also called
* Amyloidosis
* Splenic rupture
* Splenic contraction
* Splenic torsion
- (Gamma-Gandy bodies)
What can be seen in this image?
Siderotic plaques in a dog
Accumulation of minerals and also hemosiderin, giving it a brown rusty appearance.
Incidental; whenever seen in surgery or autopsy; describe this but do not mistake for pathology; very common in senile dogs.
What can be seen in this image?
Splenic amyloidosis in a dog
Key here is color change; here it appears orange, waxy
Can be primary, but in animals it is secondary to chronic inflammation; MQ –> cytokines –> amyloid fibriles –> amyloidosis
What can be seen in this image?
Normal thymus from a lamb
Thymus = pink, small in front of heart
Thymus - Structure and function
* Structure: Composed of _____ tissue and ____ tissue
* _____ and split into ____ and ____ areas
* Function: Proliferation & maturation of __ cells
epithelial, lymphoid, Lobulated, cortical, medullary, T
What can be seen here?
Thymus – Reaction pattern
* Thymic _____
* Thymic ______: Examples: ?
* Neoplasia: Thymic _____, _____
atrophy, hypoplasia, Severe combined immunodeficiency (SCID) in
Arabian foals (autosomal recessive) and Basset hounds (X-
linked), lymphoma, Thymoma
- Severe combined immunodeficiency (SCID) is a disease seen in what species?
- It is an Autosomal ________ with an absence of functional __ & ___ lymphocytes due to a defect in ?
- You see severe ________, ________ due to absence of B and T cells.
- Clinically normal at ____ b/c of maternal antibodies; after _______, began to develop secondary infections disease at ___-____ days of age. Affected foals die before __ months of age
- ________& _______ due to improper immune system.
- Common pathogens of SCID foals: ?
- Gross:
- Horse - Arabian foals, and sometimes dogs.
- recessive, B, T, DNA-dependent protein kinase (DNA-PKcs)
- lymphopenia, hypogammaglobulinemia,
- birth, weaning, 10-35, 5, Diarrhea, pneumonia,
- Equine adenovirus, Cryptosporidium parvum, and Pneumocystis carinii
- Hypoplasia of thymus, lymph nodes, spleen
* Cranioventral bronchopneumonia
* Atrophy of thymus is typical finding.
- Hypoplasia of thymus, lymph nodes, spleen
What can be seen here?
Describe the pathogenesis
Which species is this most common in?
Primary neoplasia - Thymus
Will be either:
1. Thymic lymphoma
* Neoplastic proliferation of
T-lymphocytes
* Often younger animals
(cats, calves, and dogs)
* Malignant behavior
What can be seen here?
Describe the pathogenesis
Which species is this most common in?
Primary neoplasia - Thymus
Will be either:
2. Thymoma
* Neoplastic proliferation of thymic
epithelial cells
* Less commonly seen than thymic lymphoma but are seen in dogs, sheep goats
* Slow growing, encapsulated
Mediastinal mass on animal = thymic lymphoma and thymoma are primary differentials
What can be seen here?
Thymoma is more common in a goat
What can be seen here?
Lingual tonsil (lower boxed)
What can be seen here?
What can be seen here?
What can be seen here?
Tonsil – Reaction pattern
* Lymphoid depletion (small? tonsil)
* Often in ____ infections
* Example: ?
* Inflammation (large tonsil)
* Only _____ or ______ infections (tonsils do not have _____ lymphatics = nothing can be drained into the tonsils; can therefore only have primary and hematagenous infections of tonsils; ? disease goes to afferent lymphatics and lymph nodes )
* Inflammatory polyps – ___ dogs
* Neoplasia
* _____ only (tonsils do not have afferent lymphatics)
* Example: S?
viral, classical swine fever, primary, hematogenous, afferent, old, Primary, quamous cell carcinoma, lymphoma, malignant
melanom
What can be seen here?
Classical swine fever in a pig.
Multifocal necrosis of palatine tonsils
Well demarcated
What can be seen here?
What does it arise from?
Tonsillar squamous cell carcinoma in a dog
Proliferating mass arising from palatine tonsil
Primary
