Fine Needle Aspiration Cytology

1. Fine Needle Aspiration
Cytology (FNAC)
Mithun Venugopal

2. What is FNAC?
• Fine Needle Aspiration Cytology (FNAC) is a simple, quick and
inexpensive method that is used to sample superficial masses like
those found in the neck and is usually performed in the outpatient
clinic.
• It causes minimal trauma to the patient and carries virtually no risk of
complications.
• Masses located within the region of the head and neck, including
salivary gland and thyroid gland lesions can be readily diagnosed
using this technique.

3. APPLICATIONS OF FNAC
• In routine practice, FNAC is most often used for diagnosis of palpable
mass lesions.
• Palpable lesions commonly sampled are: breast masses, enlarged
lymph nodes, enlarged thyroid and superficial soft tissue masses.
• The salivary glands, palpable abdominal lesions and the testicles are
also frequently sampled for FNAC.
• Other sites and lesions accessible to FNAC are the prostate, pelvic
organs, bone and joint spaces, lungs, retroperitoneum and orbit.

4. ADVANTAGES OF FNAC
• FNAC is an OPD procedure and requires no hospitalization while
surgical biopsies are obtained in the operation theatre and
hospitalization is often required.
• No Anaesthesia is required (except in specific circumstances), while
surgical biopsy is performed under local or general Anaesthesia.
• The procedure is quick, safe and painless.
• Multiple attempts (or repeating the procedure) are possible without
inconvenience, whereas repeating a surgical biopsy is uncomfortable
and inconvenient for the patient.

5. ADVANTAGES OF FNAC
• Results are obtained rapidly with reports being available in a matter
of hours (turn-around time of 2 to 24 hours depending on the
urgency), while histopathological reports are available after a longer
duration (turn-around time of 2 to 4 days on account of time required
for processing and sectioning of tissues).
• It is a low-cost procedure which is cost-effective.
• As the cytopathologist performs the procedure himself, he gains first-
hand knowledge of the clinical findings which facilitates
interpretation of slides and enhances diagnostic accuracy.

6. PREPARATION OF THE PATIENT
• Explain the whole procedure in brief.
• Take proper consent from the patient particularly for FNAC of deep-
seated lesions.
• Talk with the patient and give assurance to make him/her relax.
• Clean the area of the site of FNAC with a spirit swab.

7. REQUIREMENTS
NEEDLES:
• Fine needles range from 25 to 20 gauge (0.6 mm to 0.9 mm outer
diameter). The standard 21 gauge disposable needle of 38 mm length is
suitable for routine transcutaneous FNAC of palpable masses; 25 or 24
gauge disposable needles of 25 mm length are used for lymph nodes and in
children.
• Larger needles, 80 to 160 mm in length, are required for sampling the lung
and abdominal viscera; 22 to 20 gauge spinal puncture needles may be
employed for this purpose.
• Needles of up to 200 mm length are used for transrectal and transvaginal
FNAC of the prostate and ovary respectively.
• Aspiration of bony lesions may require 18 gauge (1 mm outer diameter)
needles.

8. SYRINGES:
• Syringes of 10 to 20 ml capacity are
suitable.
• Syringe holders such as the Franzen
handle permit a single hand grip during
aspiration, employing disposable syringes.
REQUIREMENTS

9. GLASS SLIDES AND FIXATIVE:
• Four or six standard microscopic glass slides and a Coplin jar
containing 95% ethyl alcohol (as a fixative) are the only other material
required for routine FNAC.
REQUIREMENTS

10. PROCEDURE OF FNAC
• Transcutaneous FNAC of palpable masses is routinely performed
without anesthesia.
• The patient is asked to lie down in a position that best exposes the
target area.
• The target area is thoroughly palpated and the firmest portion of the
lesion or mass is selected.
• The skin is cleaned with an alcohol pad.
• The mass is fixed by the palpating hand of the operator or by an
assistant.

11. • The needle is inserted into the target area.
• On reaching the lesion, the plunger of the syringe is retracted and at
least 10 ml of suction applied while moving the needle back and forth
within the lesion.
• The direction or angle of the needle may be changed to access
different areas of the lesion.
• Aspiration is terminated when aspirated material or blood becomes
visible at the base or hub of the needle.
• For diagnostic purposes, cellular material contained within the needle
is more than adequate.
PROCEDURE OF FNAC

12. • On completion of aspiration, suction is released and pressure within
the syringe allowed to equalize before withdrawing the needle.
• Withdrawing the needle with negative pressure or suction results in
blood being aspirated and cellular material being sucked into the
barrel of the syringe.
• Pressure is applied to the site of puncture by the assistant or patient
himself for 2 to 3 minutes in order to arrest bleeding.
• Aspirated material is recovered by detaching the needle from the
syringe and filling the syringe with air; the syringe and needle are
then reconnected and the aspirate expressed onto one end of a glass
slide.
PROCEDURE OF FNAC

13. 1. Take the pistol handle with attached plastic syringe and needle.
2. Immobilize the swelling by two fingers of one of your free hands.
3. Introduce the needle and move the needle to and for in the mass.
4. Apply negative suction by withdrawing the plunger.
5. Release of the plunger to stop negative suction.
6. Withdraw the needle and apply firm pressure in the site of FNAC .
7. Retract the plunger to get enough air within the syringe.
8. Reattach the needle. Eject the material on the slide.
PROCEDURE OF FNAC

15. ASPIRATION OF SPECIFIC LESIONS/BODY SITES
CYSTS:
• Cysts of the neck, thyroid, breast and other sites are often
encountered during FNAC.
• The entire fluid content is evacuated by drawing into the syringe,
collected in test tube for centrifugation and smear preparation.
• If a residual mass is palpable after removal of fluid, a fresh syringe is
used for additional aspiration of the mass in the usual manner.

16. THYROID:
• Lesions of the thyroid are aspirated
with the patient either sitting up or
lying supine with the neck extended.
• Nodules are fixed between two
palpating fingers.
• The patient is asked to avoid
swallowing during aspiration.
ASPIRATION OF SPECIFIC LESIONS/BODY SITES

17. LUNG AND RETROPERITONEUM:
• FNAC of these two sites is usually carried out under the guidance of
radiological imaging techniques.
• Local anesthesia (1% xylocaine) is advisable.
ASPIRATION OF SPECIFIC LESIONS/BODY SITES

18. COMPLICATIONS OF FNAC
• Haematomas
• Infection
• Pneumothorax (collection of air outside the lung but within the pleural cavity)
• Dissemination of tumour

19. LIMITATIONS OF FNAC
• Only a small population of cells is sampled by the procedure. The
reliability of the test, thus, depends upon the adequacy of the sample
and its representative character. An inadequate sample which is not
representative of the true lesion results in a ‘false-negative’ diagnosis.
If the FNAC report is ‘negative’ despite a strong clinical suspicion of
malignancy, the patient should be investigated further.
• Lack of requisite clinical information (e.g. size, site and character of
mass) further limit the utility of FNAC.
• Knowledge of the exact site from where the aspirate has been
obtained is crucial to the accurate interpretation of FNAC.