(W1) Describing Lesions Flashcards
Why is it important to have good descriptive skills when describing lesions?
- post mortem examination is ephemeral (only get one change to examine and take samples)
- critical to describe findings and interpretations accurately
- basis for a permanent, historical and legal record
What are the 11 descriptors when describing lesions?
- organ/tissue
- position
- number
- distribution
- contour
- size
- weight
- shape
- colour
- smell
- consistency
Organ
Know the anatomy of the species concerned (start description with the organ involved)
Position, number and weight
Position:
- be specific with location of the lesion
- use standard anatomical terms for the region of the organ/body region involved
Number:
- how many?
Weight:
- what is the weight?
- include as a % of BW (dog hear <1% of BW and cat hear less than 18-20g)
What is distribution and what words (and their definitions) can be used to indicate the distribution? Give examples of each where applicable
The spatial arrangement of lesions within the tissue
Random:
- without relationship to the architecture of the organ or tissue
- e.g. abscesses and tumour in the lungs/liver
Symmetrical:
- highlights or outlines an anatomical/physiological subunit
- e.g. metabolic disorder affecting a group or related cells in a paired organ
Focal:
- a single defined lesion on a normal background or exhibiting a different process
- e.g. an abscess in a consolidated lung
Multifocal:
- more than one discrete lesion on a background
- e.g. embolic shower
Multifocal to coalescing:
- many lesions which appear to be growing together or ‘fusing’ suggesting an active process which is expanding or not contained
- can be used to determine the stage of disease
Miliary - numerous tiny foci which are too numerous to counts
- e.g. a recent embolic shower
Segmental:
- a well defined portion of the tissue is abnormal
- often defines a vascular bed
- e.g. infarction
Diffuse:
- the whole tissue is affected
- if some of the tissue is not affected but most of it is, use ‘extensive
- can also use this in regard to sublocations e.g. the cortex of the kidney is diffusely affected
Contour of lesion
1) Raised (something added):
- fluids; blood, transudate, exudate, effusion, oedema, urine
- cells; hyperplasia, hypertrophy, neoplasia, inflammation
- tissues; fat, cartilage, bone, etc
2) Depressed (something removed)
- necrosis
- atrophy
3) Flat (not raised or depressed)
- hasn’t had time to progress or does not cause expansion or necrosis
Size of lesion (what are the 2 types and what do the sizes indicate? What are dynamic organs?
- measure in 3D
Uniform size - lesions occurring at the same time, or over a short period, and progressing at the same rate
Non- uniform size - lesions are separated in time or rate of progression
if there are multiple lesions of the same size, it normally means that they arrived at the same time and are growing at the same rate
Larger than normal - hyperplasia, hypertrophy, oedema, neoplasia, congestion, inflammation
Smaller than normal - hypoplasia, atrophy (tissue has been removed), necrosis
Often subjective, unless paired:
- which one is normal?
- use additional attributes to interpret
Dynamic organs - size due to physiological status:
- Rapidly dynamic (sec–mins) e.g. lungs, urinary bladder
- Moderately dynamic (min-hrs) e.g. spleen, GIT, brain
- Slowly dynamic (days – months) e.g. heart, liver, lymph nodes, endocrine glands
Colour (what is the colour determined by and what do the different colours indicate?
Determined by:
- innate colour and number of cells, special pigments, adipose tissue
- amount of blood in the vascular bed
Dark tissues = high pigment to tissue ratio
Light tissue = low pigment to tissue ratio
Colours:
- Red to Red-black = congestion or haemorrhage
- White/grey/yellow = lack of blood, necrosis, icterus, fibrosis
Black = melanin (melanosis - flat, melanoma - raised)
Green-black = pseudomelanosis (H2S pigments)
Green = bile, some fungi
Shape
- what does the shape of the lesion most resemble\/
- use appropriate “D or 3D terns (circular, spherical, etc)
Symmetrical shapes and patterns may reflect the underlying architecture e.g. lobes, tracts, septae
Consistency
How does it feel?
Gas - trapped in tissue (= emphysema or autolysis)
will feel crunchy due to gas tapped within tissue
Fluid - looks or feels wet (= oedema, blood, transudates, fluid rich exudate, effusions, urine)
Soft - fluid rich, cell/stroma poor
Firm - fluid poor, cell/stroma rich
Hard/gritty - mineralised stroma/matrix, cartilage, bone, calcified tissue
Smell
Distinct smell?
Foul; rotting smell, putrefactive necrosis, saprophytic bacteria
Ammonia - uraemia
No odour; aseptic process?
Distinctive Sound?
Crepitant - emphysema, gas producing bacteria, normal lung (absence = atelectasis)
Sloshing - fluid filled structure e.g. ascites, effusions, diarrhoea
