Diagnostic Pathology Flashcards
__________ is the analysis of bodily fluids via biochemical analysis, as well as cytology of tissues or fluids.
clinical pathology
T/F: diagnostic pathology involves clin path, histopath, bacteriology, virology, serology, molecular diagnostics, electron microscopy, and toxicology.
true
T/F: cytology is not always definitive and we cannot grade specimens
true
Alternative to the less-invasive, quick cytology, we can use _________ to look at pieces of tissues and the interactions occurring between cells and the adjacent tissues.
anatomic pathology
this has a longer turn around time and is more invasive. It often requires anesthesia, but it can be more definitive and allows for grading, counting of mitotic figures, etc.
what are the indications for taking tissue samples for anatomic pathology?
- initial treatment was unsuccessful
- cancer vs not
- confirm presumptive dg
- differentiate rule outs
- cytology non-diagnostic or equivocal
- ultimate cause of death or disease
- to r/o certain diseases
When taking a tissue sample, what 3 things must you consider?
- location
- size
- number
Where (location) is the BEST location of the lesion to take a sample for submission?
interface of lesion (normal to abnormal)
what size of sample is BEST and why?
the BIGGER the better. smaller samples may not be representative and are a lot more susceptible to artifacts
if you are examining a small tissue sample and you see lots of nuclear streaming, what artifact is this indicative of?
crush artifact from your forceps grasping the tissue too roughly.
How much (number) tissue sample should you be collecting?
the MORE the merrier!
some samples will not be representative of disease process you are looking for. The more you have increases the likelihood of good yield.
When submitting samples for anatomic pathology, what size should your sample be in the formalin containers and why this particular size?
< 1 cm
this is because formalin penetrates tissue at 1 cubic centimeter per 24 hr. If the sample is too big, the formalin will not be able to penetrate and fix the entire sample and it will undergo autolysis.
Samples MUST be fixed in order to be processed.
What is the appropriate tissue:formalin ratio for sample submission?
1:10
If you have a larger sample, how can you ensure the formalin reaches the middle and fixes the entire sample?
bread loaf the sample
When breadloafing samples, what should you keep intact?
the bottom margin
why should you NOT submit samples in non-lab containers?
(2 reasons)
- they are prone to leaking
- fixed tissues become rigid and cannot come out of the top of containers with narrow tops.
What are indications for necropsy?
- sudden death
- relate to clinical dg
- tx failure
- extent of dz
- catalogue dz
- herd health implications
- teaching/research
- closure for clients / owners
what organs are BEST to sample during necropsy?
- lung*
- liver*
- kidney*
- spleen*
- small intestine
- large intestine
- heart
- placenta with fetus (if possible)
T/F: when doing necropsy, you should start by sampling the GI tract and then move on to cleaner tissues.
false – always start with clean tissues and then move to GI tract.
When handling necropsy tissues, you can create crush artifacts very easily. How would you create these?
handling mucosal sides of tissues and clamping down with forceps
instead, you should handle serosal surfaces and be gentle with the forceps.
What does the sample processing system look like?
- larger samples are placed into cassettes.
- samples are covered in parafin and incubated
- parafin-covered samples are ran through a machine that cuts tiny tiny tiny (super thin!) samples that can be viewed by the microscope
What is included in histpopath report?
- clinical history and specimen site/source
- gross description
- microscopic description
- diagnosis
- comments
- signature from pathologist
T/F: there is no standardized approach or guidelines for submission, trimming, margin evaluation, or reporting of neoplastic biopsy specimens in vet med
true
what is the MOST practical surgical margin method?
radial sectioning
