24. Practical Application of Sample Collection Techniques/Diagnostic Tools in Neoplasia

True or false: All neoplasms are not the same. They look different from one another, act different, and grow different. This is why prognosis differs.

true

Since all neoplasms are different, there is no ________ cure-all.

universal

What are pros about cytologgy?

Q
E
L
C
M
I
G

• quick

• easy

• low cost

• clinician can read it

• minimal invasiveness/discomfort for patients

• individual cells

• great cellular detail

What are cons to cytology?

C
M

• can be less diagnostic

• great cellular detail

What are pros to biopsy?

better tissue detail

What are cons to biopsy?

T
M
F
A
L

• time consuming

• more invasive

• formalin fixation/time

• anatomic pathologist to read and interpret

• less cellular detail

What usually dictates what types of samples to take? What is it not always?

finances, expertise, and logistics; gold standard

True or false: You must have knowledge of the type of results you will get with each method performed. When in doubt, call and ask an expert. Do not waste time or client money in running unnecessary tests or collecting unnecessary tissues.

true

What is vital when it comes to sampling tumors or suspect tumors? What matters?

critical thinking; location

What is the general rule of thumb for biopsies, especially neoplasias? What does this mean?

interface; want to see the tumor cells but also what they are doing to the surrounding tissue

Is incisional or excisional preferred?

incisional

Is one sample sufficient for a diagnosis?

not usually

With an excisional biopsy, what should be submitted? What if it is too large?

the whole tumor; cut it so that it can be placed into multiple formalin jars, then send those to the pathologist

What is the normal ratio of formalin to tissue?

9:1 (nine parts formalin to one part tissue)

If an incisional biopsy is performed, what will give the best diagnosis?

sample from more than one site

how similar/dissimilar neoplastic cells are to normal counterparts

tumor grade

True or false: There is an underlying assumption that grade provides indication about biologic behavior, but this is not universally true.

true

What classifications are included in tumor grade?

W
M
P

• well differentiated

• moderately differentiated

• poorly differentiated

Categories translate to what?

low (grade I), medium (grade II), and high (grade III)

What else does grading consider?

other features of malignancy (invasiveness, mitoses, hemorrhage/necrosis)

What is sometimes a more useful prognostic measure than tumor grade?

tumor stage

indication of the extent of tumor growth and spread in an animal

tumor stage

What system does tumor staging use?

TNM system

What is the TNM system?

based on size of primary tumor (T), degree of lymph node involvement (N), and extent of metastasis (M)

Is there one way to diagnose all cancers?

no

What are some tumor diagnostics?

C
S
C
C
P
M

• cytology/histopathology

• special staining

• clonality assay

• cytogenic analysis

• pedigree analysis

• molecular diagnostic techniques

What can cytology and histopathology show?

features of malignancy

What special stain can be used?

IHC

What are stains within IHC? Can some cells stain positive for both?

V
C

• vimentin

• cytokeratin

yes

What stains mesenchymal?

vimentin

What stains epithelial?

cytokeratin

It is difficult to distinguish ________ hyperplasia from ________, especially in ________. Most neoplasms are ________, meaning they were derived from a single transformed cell. Inflammatory cells, as in lymphocytes, are ________.

benign; neoplasia; cytologies; clonal; polyclonal

What is cytogenic analysis evaluating?

chromosomes

What are some molecular diagnostic techniques?

M
H

• microarrays

• high-throughput sequencing

measure thousands of mRNAs

microarrays

sequence the entire genome and look for mutations

high-throughput sequencing