Fine needle aspiration cytology

Diagnostic cytology- FNAC for MBBS

1. Aspiration cytology Dr. R upinder Kaur

2. Aspiration cytology FNAC was initially conceived as a means to confirm local recurrence or metastasis of a known malignancy Valuable in the diagnosis of inflammatory, degenerative and neoplastic conditions Intraoperative cytology , imprint cytology and intervention cytology have revolutionized this method I t is being used as a valuable alternative or complement to frozen section with a comparable level of accuracy

3. Aspiration cytology FNAC is a simple procedure that involves passing a thin needle through the skin to sample fluid or tissue from a cyst or solid mass. The sample of cellular material taken during an FNA is then sent to a pathology laboratory for analysis.

4. Advantages Simple, requires little equipment Minimally invasive , no anesthesia required hence safe with minimal discomfort to the patients Rapid , rapidly repeatable, cost effective- OPD procedure Gives pre-op diagnosis Virtually every organ in the body is accessible to this method . Samples can be obtained from solid tissues that are not connected to a hollow viscus Sensitive and specific for diagnosing malignancy Diagnostic accuracy-90-99%

5. Disadvantages Requires p ractice and skills ; samples obtained may not be representative of the lesion Requires expertise in diagnosing the lesion; accuracy depends upon quality of sample and smears Relation with the underlying tissue not possible Serious complications(rare): major hemorrhage, septicemia, bile peritonitis, acute pancreatitis, pneumothorax etc. May cause local tissue changes could render subsequent histological diagnosis difficult

6. NOT A DEFINITIVE TEST ( Gold standard- Histopath )

7. Applications Applied for the diagnosis of palpable as well as non palpable lesions Palpable lesions : Lymph nodes, breast, thyroid, salivary glands, soft tissue masses and bones Non palpable masses : ( interventional) Abdominal cavity, thoracic cavity and retroperitoneum

8. Procedure Ask the patient to lie down in comfortable position Expose and palpate the target area Clean the overlying skin with rectified spirit Fix 10ml/20 ml of disposable syringe with attached needle(20-25 gauge) in Franzen handle Fix the mass by palpating hand and insert needle into the target area. Apply suction and keep changing the direction while moving needle back and forth within the lesion

9. Pr ocedure Terminate the aspiration when aspired material or blood is visible in the hub of the needle Release the suction without withdrawing the needle to equalize the p ressure within the syringe After withdrawing the needle apply pressure for 5-7 min on to the puncture sites Aspirated material is expressed on to the clean slide by first detaching the needle and filling the syringe with air and expressing it with pressure Smear are prepared as for blood smears. Smears are fixed and stained

10. Missing of the target lesion Needle within the central necrotic/cystic/hemorrhagic area devoid of diagnostic material Sampling of a dominant benign lesion and missing a smaller adjacent malignant lesion Fibrotic/ desmoplastic tissue giving a scant cell yield Unsatisfactory yield

11. Adjunct tools Cell blocks Histochemistry Immunohistochemistry Electron microscopy Flow cytometry Immuno -electron microscopy Molecular pathology -In situ hybridization, PCR etc

12. Fixatives in cytology Required for preventing the shrinkage of cells, preservation of nuclear details, kill microbes , improves optical differentiation and enhance staining properties of the tissues and cell components 95% ethyl alcohol(ethanol), ether alcohol mixture,100% methanol, 80% propanol & isopropanol and denatured alcohol Coating fixatives can also be used as an alternative- carbowax

13. Staining in cytology Two types of smears are prepared- wet fixed and air dried smears For air dried smears use of Romanaowsky stains (Wrights stain, Giemsa, May Grunwald Giemsa, Diff Quick) For wet fixed smear Papanicolaou stain and Hematoxylin and eosin is commonly used

14. Staining in cytology Air Dried Smears Nuclear and nucleolar features are less preserved Cytoplasmatic features are better preserved

15. Staining in cytology Wet Fixed Smears Nuclear and nucleolar features are better preserved Cytoplasmic changes and microorganisms are not demonstrated

16. Additional stains Ziehl-Neelsen stain PAS stain

17. Immunohistochemistry

18. AUTOMATED SYSTEMS Based on Liquid based cytology Commercially available fully or semi automated devices Make a cell monolayer on a slide after dispersion of cells from a sample in a liquid Autocyte Prep/ Sure Path ThinPrep Processor/ Cytyc corp

19. Automated Preparation and Staining Procedures Slide preparation processes are automated to provide high quality and standardized results, enabling easier interpretation and reproducibility

20. Summary Cytology is diagnostic method „ It is quick, inexpensive and accurate method , with a little risk to the patient „ Requires good communication with the clinicians and correlation with other diagnostic methods „ Requires continual learning and education