Page 295 - Textbook of Pathology, 6th Edition

viii) Following withdrawal of the needle from the lesion, 279
pressure is applied to the site of puncture by the assistant or
patient himself for 2 to 3 minutes in order to arrest bleeding
and prevent haematoma formation.
ix) Aspirated material is recovered by detaching the needle
from the syringe and filling the syringe with air; the syringe CHAPTER 11
and needle are then reconnected and the aspirate expressed
onto one end of a glass slide.

Preparation of Smears

Preparation of smears is crucial to the success of FNAC.
Poorly-prepared smears with distorted cellular morphology
will frustrate the best efforts of the most competent
cytopathologist, and often result in errors of interpretation
or in failure to arrive at any specific diagnosis. The procedure
Figure 11.11 Procedure for FNAC of palpable masses. Needle is consists of the following steps (Fig. 11.12): Basic Diagnostic Cytology
introduced into the mass (A). Plunger is retracted after needle enters the i) Aspirates deposited on the slide are inspected with the
mass (B). Suction is maintained while needle is moved back and forth
within the mass (C). Suction is released and plunger returned to original naked eye.
position before needle is withdrawn (D). ii) Semisolid particulate aspirates are crush-smeared by flat
pressure with a glass slide or a thick coverslip. Even and
ii) The target area is thoroughly palpated and the firmest gentle pressure is required to avoid traumatising cells.
portion of the lesion or mass delineated. Droplets of fluid or bloody material are gathered under the
iii) The skin is cleaned with an alcohol pad. edge of the angled smearing slide or coverslip and pulled
iv) The mass is fixed by the palpating hand of the operator like a blood smear. Particulate material, which collects along
or by an assistant; gloves may be used for protection of the the edges and at the end of the smear, is then crush-smeared
operator and the assistant. by flattening the smearing slide.
v) The needle is inserted into the target area. On reaching iii) Prepared smears are either wet-fixed or air-dried. Half the
the lesion, the plunger of the syringe is retracted and at least number of smears are immediately immersed in 95% ethanol,
10 ml of suction applied while moving the needle back and transported to the laboratory in the fixative, and used for
forth within the lesion; the direction or angle of the needle Papanicolaou or H&E staining. The remaining smears are
may be changed to access different areas of the lesion. air-dried, wrapped in tissue paper for transport to the labo-
vi) Aspiration is terminated when aspirated material or blood ratory, and stained by Romanowsky stains (e.g. Leishman’s,
becomes visible at the base or hub of the needle. For May-Grünwald-Giemsa). Most cytopathologists use both
diagnostic purposes, cellular material contained within the wet-fixed and air-dried smears—the wet-fixed smears
needle is more than adequate; material drawn into the barrel provide excellent nuclear detail while the air-dried smears
of the syringe is not recovered since it is of no use for cytologic yields information about the cytoplasm and the background.
diagnosis. The general properties of wet-fixed and air-dried smears
vii) On completion of aspiration, suction is released and outlined in Table 11.8.
pressure within the syringe allowed to equalise before
withdrawing the needle. Withdrawing the needle with Special and Ancillary Studies
negative pressure or suction results in blood being aspirated
and cellular material being sucked into the barrel of the Aspirates may also be studied by special stains and tech-
syringe, thus lost to interpretation. niques for specific purposes as under:

Figure 11.12 Preparation of smears. Semisolid aspirates are crush-smeared by flat pressure with cover slip or glass slide (A). Fluid or blood
droplet is collected along edge of spreader (B), and pulled as for peripheral blood films (C). Particles at the end of the smear are crush-smeared (D).