Introduction to Pathology Flashcards
what is pathology
- study of disease (pathos - disease; logos - study)
- study of structure, biochemical and functional changes in cells, tissue, and organs that underlie disease
- uses molecular, microbiologic, immunologic and morphologic techniques
- bridges btwn basic science and clinical medicine
- diagnostic medicine
what do pathologists do
- run laboratory
- perform anatomic pathology
- perform clinical pathology
- does basic/clinical research
What are the Anatomic Pathology Specialties?
- cytology
- surgical pathology
- hematopathology
- autopsy
what do cytologists do
- pap smears
- FNA
- fluids
What do surgical pathologist do
- general surgical pathology
- neuropathology
- renal pathology
- dermatopathology
- GI/Liver
- transplant pathology
What type of test do anatomic pathologist perform
- primarily morphological
- gross
- light microscopy
- special stains
- IHC (immunohistochemical)
- immunofluorescence
- EM
What type of test do clinical pathologists perform?
- hematology (blood count, coagulation factors)
- blood bank
- chemistry
- immunology/serology (titers)
- microbiology (culture and test for drug sensitvity)
- cytogenetics (chromosomes - see translocation)
how is a surgical specimen processed during a gross exam
- describe/dictate specimen
- photograph
- ink margins
- decalcify
- select tissue for histology
- select tissue for other studies (ie. flow cytometry, culture, molecular pathology, EM
- pathologist assistant may do all this
Histrological Processing
- overnight processing
- embed tissue
- cut w/ microtome (water bath, dry)
- stain (usual H&E stain)
after a histological exam of a gross specimen what does the pathologist do?
- may order additional stains
- dicates or writes report
- transcription
- electonic sign out of case
at what elapsed time does te pathologist read slides
elapsed time: 24-48 hrs
when does it take more than 24-48 hrs to get diagnosis from gross specimens
- big specimens
- additional sampling for complicated cases
- bone/calcium decalcification
- need for additional stains/studies (usually tumors)
Hematoxylin & Eosin (H&E) used for
-nuclear material/nucleus
what is a Giemsa Stain used for
-blood smear, bone marrow
what is a Papanicolaou stain used for
-cervical pap smears
what is a Diff Quick stain used for
-air dried smears
Types of Stains
- H&E
- Giemsa Stain
- Papanicolaou Stain
- Diff Quik
- special histochemical stains
- immunohistochemistry
Characteristics of a H&E stain
Eosin - red (cytoplasm, acidic proteins)
Hematoxylin - blue (DNA/RNA bases)
what does a Pap stain look like
keratin: orange
nuclei: blue black
cytoplasm: blue/green/pink
what are the histochemical stains, “bug stains”
- gomori silver
- acid fast
- gram stain
- PAS - polysaccharides + mucopolysaccarides
what is a gomori silver stain used for
-fungus
what is an acid fast stain used for
TB
what is a gram stain used for
bacteria
what is a PAS (polysaccharides + mucopolysaccarides) stain used for?
-fungus
special histochemical stains used for Liver panel, bone marrow
- Prussian Blue
- Trichrome
- Reticulin
- PAS
- DPAS
- Van Geisen
- Mucin or Mucicarmine
what is a Prussian blue stain used for
-iron (liver)
characteristics of trichrome stain
- cells red
- fibrous tissue blue
Characteristics of reticulin stain
reticulin black
characteristis of PAS (polysaccharides + mucopolysaccarides)
magenta
characteristics of DPAS stain
- digest glycogen
- mucopolysaccharides only magenta
characteristics of Van Geisen
-elastic black
characteristics of mucin or mucicarmine
-mucin pink
when is immunohistochemistry used
- used to identify primary Ab to Ag of interest of membrane/nuclear material/cytoplasmic material
- second Ab is required to have a chromagen which colors/tags the AB
uses of immunohistochemistry
- identify tumor types
- identify normal cells
- therapetuic implications
how can tumors be identified
carcinoma = keratin positive
B cell Lymphoma = CD45 and CD20 positive
how do you identify normal cells
p63 highlights myoepithelial cells
what are the therapetutic implications of using immunohistochemistry
- over expression of genes = susceptibility to specific therapy
- estrogen receptors & Tamoxifen (ie. is a breast cell estrogen positive)
C Kit (CD117) & Gleevac (if CD117 + use Gleevac)
colorectal adenocarcinoma is positive for what CK
CK 20+ AND CK7 positive
estrogen receptor is what type of stain
nuclear staining
expression by tumor means sensitivity to
estrogen antagonists when using IHC estrogen receptors
what type of microscope is used when vieweing kidney specimens
electron microscopy
when are frozen sections used
- fast results
- when results will affect procedure
- intraoperatives
~20 min time frame
disadvantage of using frozen sections
- some compromise of quality
- small eroor rate <5%
- freezing artifact
- limited sample
how are pap smears performed
- brush/preservative fluid
- spin fluid on to slide
- stain
- screened by cytotechnologist
- evaluated by pathologist
what does a hematophatologist do
- bone marrow biopsy
- lymph node biopsy
- biopsy of any tissue involved by lymphoma
- fine needle aspirate of lymph node
- flow cytometric analysis
- molecular analysis
autopsy
-disection of the body of a deceased patient to determine:
- cause of death
- natural course of a disease
- presence of concurrent disease(s), significant or incidental
- effect(s) of therapy
- clinicopathologic correlation
a good autopsy required
- knowledge of the clinical details of the case
- broad general medical knowledge
- good observational skills
medical autopsy is directed by who
-a pathologist
when is a medical autopsy performed
inpatient death: adult, stillborn, newborn
outpatient death for a patient folloed by a staff physician
release of a forensic case by meical examiner
forensic autopsy directed by
medical examiner or coroner
when is a forensic autopsy performed
- criminal, violent, accidental, unattended or suspicious death
- unclaimed body
what are the 4 main reasons that autopsies are declined
- social
* family permission required, religious restrictions, lack of understanding by family and physicians - economic
* cost to hospital, lack of reimbursement through insurance - meidcal
- Physician overconfidence (imaging, serology)
- Fear of transmission of infectious disease
- Failure to use information
- Pathologist apathy
- Poor turn-around-time
- fear or legal action
advantages of autopsies
- unexpected findings
- valuable teaching and research
- enhance communication
- reduce/eliminates suspicions
- reassurance for family and physician
- reduces claims/malpractice suit
- accurate mortality statistics
virchow’s node
-left supraclavicular node from GI malignancy
Virchow autopsy method
-one organ at a time
Virchow’s Triad
thrombosis
what was rudolph virchow
father of modern pathology
