2. History
⢠1896- cell block prepared in celloidin embedding medium
⢠1901- centrifugation was used to increase cellularity
⢠1959- bacterial agar introduced for preparing cell block
⢠1973- plasma thrombin clot introduced
⢠2007- automated cell block system (cellient)
3. Fine needle aspiration cytology
(FNAC)
⢠FNAC is the study of cellular
samples obtained through a fine
needle
⢠It is useful in palpable lesions of
thyroid, lymph nodes, salivary
glands, breast and subcutaneous
tissues
4. ⢠Relatively painless and inexpensive
⢠Provides unequivocal diagnosis (sensitivity and specificity âĽ
90%)
⢠Highly suitable in debilitated patients and multiple lesions
⢠Low risk of complications
⢠Easily repeatable
6. ⢠Cell blocks contain aspirated materials
embedded in paraffin that broaden the
diagnostic value of cytology specimens
and are complementary to cytology
preparations
⢠It employs retrieval of small tissue
fragments from FNA specimen which
are processed to form a paraffin block
What is a cell block ?
7. Cell blocks offer the opportunity to examine the
histological structure and allows the use of ancillary
tests
Cytology Histopathology
Bridge
(Cell blocks)
8. ⢠Acquisition of tissue for cell block can increase both
diagnostic sensitivity and specificity (through both cellular
morphology and ancillary testing)
⢠It requires minimal effort and is cost efficient.
⢠Moreover, tissue preserved in cell block can be stored
easily
Need for Cell Block
11. Salvaging of grossly visible flecks of tissue or Sediment
Fixation by formalin or any other fixative
Paraffin embedding
Cutting
Staining
12. 1. Fixed sediment method
2. Histogel method
3. Gelatin embedding
4. Bacterial agar method
5. Plasma thrombin method
6. Colloidion bag
Methods of cell block preparation
7. Scraping of cytology
smears
8. Cell blocks from Millipore
9. Automated preparation
10.Albumin method
13. Fixed sedimentation method
Take 100% alcohol : distilled water (1:1)
Put the aspirate in it
Centrifuge @1500rpm for 6 min
PELLET
100% alcohol + 40% formalin (9:1)
45 min stand
Centrifuge @1500rpm for 6 min
Pellet dislodge
Block
14. Histogel method
⢠Specimen remains surrounded by Histogel
⢠Can be used if very scant material is aspirated
⢠Better than agarose gel and thromboplastin
⢠Doesnât retain stain particles
17. Other methods
⢠Gelatin method- 2% molten gelatin is used
⢠Bacterial Agar method- 3% agar is used
18. Clot method
Aspirate 10% formalin
from the container in
which the specimen is
to be submitted for cell
block processing. This
dislodges the clot from
syringe wall.
Let the remaining aspirate
clot in the syringe for 5 to 7
minutes (slightly longer than
the clotting time).
Gently and firmly
remove the
plunger of the
syringe .
Transfer the
aspirated formalin
with dislodged clot
in to the specimen
container with 10%
formalin fixative
20. 1. Cell Block is simple , reproducible and readily available in
routine labs
2. Increased cellularity
3. Better morphological and architectural patterns
4. Additional yield of cells, thereby increasing diagnostic yield
5. Unlimited storage of the sample
6. Application of ancillary studies (ICC and molecular testing)
Advantages
21. Disadvantages of cell block
⢠Compared to routine smears takes longer time
⢠Distortion artifact
26. 1- Most common method of cell block
preparation
a) Fixed sedimentation method
b) Plasma thrombin method
c) Agar method
d) Gelatin method
27. 2- % of alcohol and formalin in fixed sediment
method is-
a) 100% alcohol and 40% formalin
b) 90% alcohol and 40% formalin
c) 40% alcohol and 40% formalin
d) 40% alcohol and 100% formalin
28. 3- % of agar used in bacterial agar method-
a) 1%
b) 2%
c) 3%
d) 4%
29. 4- amount of plasma and thrombin used in
plasma thrombin method?
a) 1:1
b) 1:2
c) 2:1
d) 3:1
30. 5- Ratio of formalin(40%) and alcohol(100%) is-
a) 1:9
b) 9:1
c) 2:3
d) 3:2