Cell block and its diagnostic utility

role of cell block in pathology

1. CELL BLOCK PREPARATION, DIAGNOSTIC UTILITY AND ITS RELEVANCE Dr. Gaurav kumar King Georges Medical University

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 ≥ 90%) Highly suitable in debilitated patients and multiple lesions Low risk of complications Easily repeatable

5. FNAC/ Fluids Cytosmears Cytosmears Benign CELL BLOCKS Special stains ICC Molecular testing

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

9. Material required for cell block

10. Specimens FNAC SPUTUM EFFUSION FLUIDS URINE LAVAGES & WASHINGS

11. Salvaging of grossly visible flecks of tissue or S ediment Fixation by formalin or any other fixative Paraffin embedding Cutting Staining

12. Fixed sediment method Histogel method Gelatin embedding Bacterial agar method Plasma thrombin method Colloidion bag Methods of cell block preparation Scraping of cytology smears Cell blocks from Millipore Automated preparation 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 Doesn’t retain stain particles

15. Histogel method

16. Plasma thrombin method Equal amount of plasma and thrombin

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

19. Automated cell block ( cellient )

20. Cell Block is simple , reproducible and readily available in routine labs Increased cellularity Better morphological and architectural patterns Additional yield of cells, thereby increasing diagnostic yield Unlimited storage of the sample Application of ancillary studies (ICC and molecular testing) Advantages

21. Disadvantages of cell block Compared to rou ti ne smears takes longer ti me Distortion artifact

22. Cytosmears v/s Cell Block

23. Refrences G.W. Gill, cytopreparation : principles & practice, essentials in cytopathology12, Springer science Shidham & Epple Ch 14 ‘ Cytopathologic Diagnosis of Serous Fluids’ :Elsevier (W. B. Saunders Company ) Koss diagnostic and cytology and its histopathologic bases 5 th edition

24. Thank you

25. MCQ

26. 1- Most common method of cell block preparation Fixed sedimentation method Plasma thrombin method Agar method Gelatin method

27. 2- % of alcohol and formalin in fixed sediment method is- 100% alcohol and 40% formalin 90% alcohol and 40% formalin 40% alcohol and 40% formalin 40% alcohol and 100% formalin

28. 3- % of agar used in bacterial agar method- 1% 2% 3% 4%

29. 4- amount of plasma and thrombin used in plasma thrombin method? 1:1 1:2 2:1 3:1

30. 5- Ratio of formalin(40%) and alcohol(100%) is- 1:9 9:1 2 :3 3:2