Gross pathology Flashcards
What criteria should be used to describe lesions
Location
Number/extent
Demarcation
Distribution
Colour
Size
Shape
Consistency & texture
Name these types of distribution
Name these shapes/demarcations
What do the different colours in pathology mean
What are some possible consistencies and textures?
Describe this lesion
On (1.) forelimb, clipped area measuring 10 x 5 cm. Within clipped area is (2.) 1 (3.) well-demarcated, (4.) focal, (5.) pink to dark red, (6.) 3cm in diameter x 2cm height (7.) round, raised, (8.) firm, hairless mass
(Probably a mast cell tumour)
Describe this lesion in a dog
(1.) stomach was (4.) diffusely distended, (8). gas-filled & (5.) diffusely dark red
(Stomach: Necrosis, diffuse, severe, acute with dilation. Gastric torsion?)
Describe this lesion in a dog
Affecting (2.) 20% of (1.) right kidney, within renal cortex & extending into medulla, was a (4.) focal, (3.) well-demarcated, (6.) 3 x 2cm, (5.) light tan to dark red, (7.) wedge-shaped lesion
Describe this lesion in a cat
Affecting (2.) 30% of tongue, (1.) on left underside & extending to lingual surface, there was (4.) a focal, (3.) moderately well demarcated, (5.) pink to red, (6.) 5 x 2 x 1cm, (7.) oval, (8.) multinodular, firm mass
(tongue: probably squamous cell carcinoma)
Describe this lesion in a horse
(4.) Focally extensively, (1.) effacing perineum & base of tail, was (2.) a (3.) well-demarcated, (5.) black to red, (6.) approx 1m by 50cm x 10cm, (8.) ulcerated, multinodular mass
(probably a melanoma)
Describe this lesion in a chicken
Adhered to viscera & mesentery of ileum & paired caeca, were numerous, well demarcated, multifocal, up to 2cm in diameter, pink to tan, round firm masses
(Ileum, caeca: probably adenocarcinoma arising from ovary, oviduct or pancreas as these common in ageing hens)
describe this lesion in a cow
Affecting up to 90% of mammary gland, there was multifocal to coalescing, poorly demarcated areas of grey to light pink, friable tissue, admixed with haemorrhage & abundant light pink purulent exudate (pus)
What are the possible causes of cell injury?
Oxygen deprivation
Physical agents
Chemical agents and drugs
Infectious agents
Immunologic reactions
Genetic derangements
Nutritional imbalances
What are some possible causes of hypoxia (oxygen deficiency)?
Reduced blood flow (ischaemia)
Inadequate oxygenation of blood (cardiorespiratory failure)
Decreased oxygen-carrying capacity of blood (anaemia, carbon monoxide poisoning, blood loss)
Give examples of physical agents that can cause cell injury
Mechanical trauma
Extremes of temperature
Radiation
Electric shock
Give examples of chemical agents & drugs that can cause cell injury
Hypertonic concentrations (glucose, salt)
Poisons (arsenic, cyanide)
Environmental pollutants
Insecticides, herbicides
Therapeutic drugs
Give examples of infectious agents that can cause cell injury
Viruses (and prions)
Bacteria
Fungi
Protozoa
Helminths
Other (eg ecto-)parasites
Give examples of immunologic reactions that can cause cell injury
Immune reactions to external agents (microbes) & environmental substances
Immune reactions to endogenous self-antigens (autoimmune diseases)
What is reversible degeneration?
Early response to cell injury
Depletion of cellular energy stores (ATP):
- cellular swelling/fatty change
- alteration of intracellular organelles
- affects functionality of cell
reversible if damaging stimulus is removed
Why do cells swell after injury?
What causes fatty changes after cell injury?
What are some irreversible cell injuries?
Necrosis & apoptosis
describe necrosis after cell injury
Always pathologic
Cell membranes damaged
Often with inflammation (neutrophils attack leaked cell content)
Describe apoptosis after cell injury
May be physiologic or pathologic
Cell membranes intact
No inflammation
Cell suicide/programmed death
Cell shrinks
What are the microscopic morphologic alterations that occur in necrosis?
Label the histological signs of necrosis
Give examples of the patterns of tissue necrosis (macroscopic morphologic alterations)
Coagulative necrosis
Liquefactive necrosis
Gangrenous necrosis
Caseous necrosis
Fat necrosis
Describe coagulative necrosis
Localised area of coagulative necrosis caused by ischaemia due to vascular obstruction
Describe liquefactive necrosis
Collection of necrotic neutrophils & tissue debris (pus)
(abscess = encapsulated pus)
Describe gangrenous necrosis
Variant of coagulative necrosis
Usually applied to a limb that has lost its blood supply (also tail, ears, udder)
3 types of gangrene: dry, moist or gas
Describe caseous necrosis
Conversion of dead cells into friable mass resembling cheese
Typically more chronic than coagulation necrosis
e.g. Tuberculosis, Pseudotuberculosis
Describe fat necrosis
Focal areas of fat destruction
Fat appears white, firm & chalky
Typically resulting from release of pancreatic lipases
What are the microscopic morphologic alterations seen after apoptosis?
Cell shrinkage
Chromatin condensation
Cytoplasmic blebs & apoptotic bodies
Phagocytosis of apoptotic cells or cell bodies
What are cell/tissue adaptations?
Reversible functional & structural responses to more severe physiological stresses & some pathologic stimuli , allowing cell to survive & continue to function
Changes in size, number, phenotype, metabolic activity or function of cells
Cell injury once limits of adaptive responses are exceeded
What are the types of tissue adaptations & their causes?
Describe the ability of labile cells to adapt
Routinely proliferate
e.g. epidermis, intestinal epithelium, bone marrow cells
Describe the ability of stable cells to adapt
Intermediate in ability of regenerate/divide
e.g. bone, cartilage, smooth muscle
Describe the ability of permanent cells to adapt
Very little capacity to regenerate
e.g. neurons, cardiac/skeletal muscle cells
In what cell types can hypertrophy occur
most organs/tissues
Mainly in stable or permanent cells
In what cell types can hyperplasia occur
Only in organs with dividing cells
Mainly labile cells
describe hypertrophy & its stimuli
Increase in size of cells (by producing more organelles) resulting in increase in size of organ
Stimuli:
- increased functional demand (e.g. muscle)
- Stimulation by hormones (e.g. uterus during pregnancy)
- growth factors or viruses
Not always useful as blood supply may not increase adequately to serve increased mass
(Hypertrophy & hyperplasia often occur together & have same gross appearance)
describe hyperplasia & its stimuli
Increase in number of cells in organ/tissue, resulting in increased mass/size
Stimuli:
- increased functional demand (e.g. muscle)
- Stimulation by hormones (e.g. uterus during pregnancy)
- growth factors or viruses
(Hypertrophy & hyperplasia often occur together & have same gross appearance)
What is atrophy
decrease in cell size & number, resulting in reduced size of organ/tissue
Give examples of physiologic atrophy
e.g. during embryonal/fetal development, uterus atrophy after parturition
Give examples of pathologic atrophy
Decreased workload (atrophy of disuse)
Loss of innervation (denervation atrophy)
Diminished blood supply
Inadequate nutrition
Loss of endocrine stimulation
Pressure
describe metaplasia & its causes
Potentially reversible change in which a differentiated cell type (epithelial or mesenchymal) is replaced by another cell type
Most common: columnar to squamous epithelial
Causes:
- chronic irritation
- deficiencies (e.g. Vit A)
- result of cell/tissue injury
- oestrogen toxicity
What are the types of disorders of growth & their definitions
Agenesis: never developed
Aplasia: started development but stopped early
Atresia: absence of an orifice
Hypoplasia: incomplete development
Dysplasia: disordered growth
Neoplasia: abnormal growth of cells
Small intestine: enteritis, necrohaemorrhagic, segmental, acute, severe
Aetiology: Parvovirus infection
No, this is livor mortis
hemangiosarcoma
Haired skin of face & neck is multifocally elevated by well-demarcated, round, red, hairless, firm, nodular masses that measure approx 5-10mm in diameter
Heart, left ventricle: Myocardial hypertrophy, diffuse, severe, chronic
Lungs & thoracic cavity: haemorrhage, multifocal to coalescing, severe, acute with moderate haemothorax
(In this case haemorrhage was due to ingestion of anticoagulant rodenticides)
Conjunctiva: Mucopurulent exudative conjunctivitis, marked, regional, acute to subacute with regional, moderate, oedema
Cerebrum: Meningioma
No, its not a lesion
This is pseudomelanosis
Mandibular oral mucosa: Oral malignant melanoma
Very aggressive
Neoplasm is invading into bony structures of mandible
Not a lesion
Body as a whole: oedema, diffuse, severe (consistent with anasarca)
possible causes:
- decreased intravascular oncotic pressure
- increased venous hydrostatic pressure
Long bone: physeal fracture, focally extensive, severe, acute
haired skin over dorsal scapula: important differential in this location is feline injection site sarcoma
These neoplasms can be very aggressive
Urinary bladder: urolithiasis & chronic, diffuse, moderate, cystitis
Diaphragm: herniation of abdominal viscera, focal, severe, acute with compression of pulmonary parenchyma
Within duodenum is focal, full thickness, perforation with 1.5cm diameter
Haired skin, chin: folliculitis, multifocal, moderate, chronic
Thyroid glands: adenomatous hyperplasia, multifocal & bilateral, severe, chronic
Perianal gland: adenoma
