Principles of Diagnostic Pathology

Question 1

What is included under diagnostic pathology?

Answer 1

Clin path (hematology and cytology), histopath (biopsy and necropsy), bacteriology, virology, serology, molecular diagnostics, electron microscopy, toxicology

Question 2

What are the advantages and disadvantages of cytology?

Answer 2

Quick and less-intrusive, but not always definitive and you cant always grade a lesion based on this

Question 3

What are the advantages and disadvantages of anatomic pathology?

Answer 3

Advantages: can see interactions between cells and adjacent tissue, can get more definitive diagnosis, can grade lesions

Disadvantages: more invasive, often requires anesthesia, long turnaround time

Question 4

What are the indications for biopsy?

Answer 4

When the initial treatment was unsuccessful, when you are trying to rule out cancer, when you want to confirm a presumptive diagnosis, to differentiate amongst rule outs, when cytology was equivocal, to determine cause of death or disease

Question 5

Where is the best place to sample a lesion?

Answer 5

At the interface between healthy and unhealthy tissue

Question 6

T/F: Bigger is always better for sample collection

Answer 6

For the most part this is true, but you have to make sure formalin can penetrate. Can sometimes be better to get multiple small samples from different locations

Question 7

What are the indications for necropsy?

Answer 7

Sudden death, treatment failure, cataloguing disease, determining herd health implications, teaching/research, determining extent of disease, determining accuracy of clinical diagnosis, closure for owners

Question 8

Name some tips/tricks for necropsies

Answer 8

-start with clean tissue, finish with GI samples
-dont handle mucosal side as it is fragile, handle serosal surface to avoid artifacts
-dont clamp down hard with forceps
-submit the placenta with fetal tissues
-bread load large parenchymal organs

Question 9

What samples are always essential to send out for necropsy?

Answer 9

Lung, liver, kidney, spleen, small intestine, large intestine, heart, as well as all lesions found

Question 10

What size should your sample be for sending out?

Answer 10

<1 cm, 1:10 tissue: formalin ratio

Question 11

How are surgical margins assessed in vet med?

Answer 11

There is no standardized approach or guideline for the submission, trimming, margin evaluation, or reporting of neoplastic biopsy specimens
- generally in vet med you look at one longitudinal view in each direction for assessing margins
-can miss a lot of the margin and we would not no based on biopsy