Gross Techniques In Surgical
Pathology
Introduction
The routine work associated with a surgical
pathology specimen includes gross &
microscopic examinations.
Gross examinations give an idea about size
,shape of specimen &any gross
abnormality like ulceration, nodularity.
The dissection, gross description &selection
of sections for microscopic study is a
crucial part of pathologic examinations
Preparations of sections for
histopathology
1- paraffin embedding method ( the routine
& widely used procedure).
2- frozen section (intra-operative).
3- cytological diagnosis (exfoliative & fine
needle aspiration cytology.
4- digital pathology & telepathology.
Paraffin embedding method
Include the following principle steps:
1- fixation:- to preserve the tissue,
fixatives include formaldehyde, Zenker’s
solution, picric acid, Bouin’s solution,
The best fixative is 10% buffered formalin
Advantages of Formalin
1- cheep.
2- always available.
3- good penetration into tissue.
4- cause little shrinkage.
5- preserve RBCs & fatty tissue.
6- special stains can be used on tissues
fixed with it.
7- preserve color of the tissue.
8- good hardening.
Disadvantages of Formalin
1- if tissue preserved in formalin for long time,
formic acid will be formed which affect
stainability of tissue with different stains, so it
should be changed every 3-6 months.
2- when formalin solution is stored for long period
a white precipitate of para formaldehyde which
will not affect the efficiency of formalin as a
fixative & can be removed by alcohol.
3- cannot preserve glycogen.
2- Dehydration:- by using different
concentrations of alcohol.
3- Clearing:- by using xyline.
4- Paraffin impregnation.
5- Embedding:- to make the tissue as a
block of hard paraffin
6- Sectioning:- by using a microtome, the
tissue is sliced into very thin sections ranging
from 4-6 micrometer in thickness.
7- Attaching sections to the slides.
8- Deparaffinization:- by using xylol &
alcohol until the paraffin is dissolved.
9- Staining:- the standard staining method is
H & E which stain the nucleus blue (basophilic)
& the cytoplasm pink-red (acidophilic).
10- Mounting:- by using DPX &cover slip.
Special Techniques In Surgical Pathology
1- Special stains like PAS (periodic acid schiff) stain, Gram,
Giemsa, Ziel-Neelson.
2- Enzyme histochemistry.
3- Tissue culturing.
4- Histometry.
5- X-ray microanalysis.
6- Electron microscopy.
7- Immunohistochemistry, sensitive &specific.
8- Flow cytometry.
9- Cytogenetics.
10- Polymerase Chain Reaction (PCR).