Flashcards in Lesion descripton and recognition Deck (28):
What is the initial step in examining a specimen?
Identify the species and the tissue/organ
What characteristics need to be described on a lesion?
Where is it?
Any special features
examine the cut surface
What terms can be used to describe where the lesion is?
Focal- one part Multifocal to coalescing- multifocal join up
Solitary Segmental- portion of a tubular organ
Multifocal Miliary- multiple small lesions
Diffuse- whole organ
Why are size and weight of the lesion important?
Size can be given as a linear measurement in two or three dimensions and the proportion of the organ affected should be given.
Weight- must be relative to the weight of the animal.
Volume- again only relevant if the weight of the animal is known.
What terms can be used to describe the shape of a lesion?
Circular, oval, nodular. Comment on the borders- well/poorly defined, demarcated and the surface:
flat (flush with the surface)
elevated, depressed umbilicated, pedunculated (lipoma), sessile (wide base attachment)
How should colour be described?
primary colour plus light/dark, shiny/dull
What are the criteria looked for in judging the consistency of a lesion?
type: soft, firm, hard
degree: slight, moderate, marked
cohesion: friable, elastic
Give an example of the odour of a lesion being important?
Ammonia on the breath- kidney disease
What do you look for in surface features and the cut surface?
1) free fluid, blood, exudate
2) consistency, amount of blood, capsule or borders to the lesion once into the organ.
What do you do if the whole lesion cannot be submitted to the lab?
Send a portion but with a diagrammatic representation of the lesion.
What two types of spread of a lesion are there?
Haematogenous/systemic- if the lesions are spread evenly throughout the organ.
Aerogenous portal of entry- e.g. in the cranioventral regions of the lungs.
What does a raised lesion suggest?
That something has been added. e.g. a parasite with surrounding inflammation- Muellerius capillaris in sheep lungs.
What do depressed lesions imply?
Something has be lost e.g. due to necrosis, traction on adjacent tissue by scar tissue or collapse of the lung.
What do flat lesions imply?
An acute process has occurred where has not been time for cells/fluid to accumulate.
How does demarcation vary between lesions?
Benign tumour- well demarcated because it grows by expansion
Inflammatory lesions- if the are chronic they are surrounded by fibrosis so are well demarcated whereas an acute lesion will be poorly demarcated.
Why the the size of the lesion important?
Particularly if you are submitting only part of the lesion to a lab. It is also important for assessing the functional significance e.g. one small abscess in the liver is not as significant as complete hepatic fibrosis that affects the whole organ.
What is the significance of an organ being red/black in colour?
Due to an increase in the amount of blood and can indicate congestion or haemorrhage. If the haemorrhage is significant it will be very dark (deoxy Hb) and will be most obvious in light coloured tissue e.g. brain vs spleen. If there is also a nodular lesion then consider a haematoma or vascular lesion.
What this the significance of a black/brown colour?
Melanin, exogenous carbon, putrefactive bacteria, haemosiderin.
If it is a mass- melanoma (melanoma containing neoplasm)
Black and not raised- melanosis
PM change- pseudomelanosis
Haemosiderosis- old congestion
What is the significance of a green colour?
Usually a bile pigment seen in areas of the liver and the intestine adjacent to the gall bladder. Some fungal pathogens in the resp tract have this colour.
What is the significance of a yellow colour?
fat, bile pigment (bilirubin), fibrin, cellular exudates, neoplams or due to icterus (biliverdin) or lipidosis.
What is the significance of the colour white?
Exudates/neoplasia or CT
What are the possible causes for fluid around a lesion?
oedema (clear), serofibrinous (inflammatory), urine, turbid fluid (cellular elements, inflammation, lymphatics or neoplastic effusion),
When is a lesion described as soft?
Normal consistency for many tissue- those with little stroma or loosely organised.
When is a lesion described as firm?
Normal in fluid-poor, cell rich tissues. Seen in many inflammatory or proliferative lesions and any addition of scar tissue.
When is a lesion described as hard?
It implies mineral density e.g. cartilage, bone or mineral deposits.
When is a differential diagnosis simple?
If based on the gross appearance of the lesion e.g. fractured femur or ruptured spleen (trauma associated)
Or when there are pathognomic lesion (associated with a particular disease).
When is a differential diagnosis not simple?
When the lesion is not pathognomic. e.g. a solitary mass can be a focus of inflammation, a neoplasm, a haematoma or a cyst. Examination as prev. described will narrow down what the lesion is.
But sometimes you will require histology.