20
Fine-Needle Aspiration Biopsy Techniques
has become so important in the management of breast cancer
that great effort has been put into standardizing the method-
ology to obtain meaningful and accurate results. FNA is not
included as a specimen type in recently published guidelines for
testing Her-2 neu.57
There continues to be remarkable growth in the number of
antibodies available for detecting cell products by immuno-
histochemistry. Many of these reagents are equally applicable
to aspiration samples, particularly cell blocks and/or micro-
cores.3158 Immunocytochemistry can be performed on air-dried,
alcohol-fixed, or previously Papanicolaou-stained smears in
an effort to successfully detect a number of antigens.59 While
immunocytochemistry can be performed on direct smears,
more consistent results have been obtained in the author's labo-
ratory with cytospin preparations, cell blocks, or microcores.60-62
Low cellularity is the only limitation and is most often a factor
with cell-block specimens. It is therefore important to have the
cytopathologists evaluate initial smears, determine at least a pre-
sumptive diagnosis, and obtain additional samples as needed
to provide adequate cellularity for these special techniques. Par-
ticularly with lymphoproliferative diseases, adequate cells for
preparing a number of cytospins can be obtained by FNA and a
panel of markers then used to characterize and aid in the diag-
nosis of malignant lymphomas versus a reactive lymphoid pro-
liferation versus another type of neoplasm. Good protocols for
the application of molecular methods for diagnosing Hodgkin's
and non-Hodgkin's lymphomas from aspiration samples have
been developed.63-66
While there have been advocates for ultrastructural study to
characterize neoplasms from samples obtained by aspiration
biopsy,67 currently electron microscopy seems to have a very
limited role for the diagnosis of neoplasms both by aspiration
biopsy and in the practice of general surgical pathology.68 The
sampling technique for electron microscopy is, however, quite
simple. Simply obtain a separate aspiration sample and place
it directly into buffered glutaraldehyde fixative, centrifuge the
specimen, and handle the resulting cell button by standard tech-
niques for electron microscopic studies. Because the aspirate
sample is directly and immediately fixed after being taken, the
quality of preservation of the cell organelles is excellent.52
Applications of molecular biology for the diagnosis of
disease have continued to expand and increase both in surgi-
cal pathology and cytopathology.48,69 Detection of oncogene
c-erbB-2 in breast cancer and bcl-2 oncogene in lymphoid tissue
from FNA samples has been reported.28,55 Both fresh and archi-
val FNA samples (smears) have been successfully used.59,60,71
Determining clonality is quite useful in the diagnosis of lym-
phomas, and these techniques have been applied to aspiration
biopsy samples.72-74 A portion or separate aspirate can be set
aside at the time the patient's lesion is biopsied for the applica-
tion of molecular diagnostics as needed. An expanding variety
of probes for detecting gene rearrangements and specific tumor
markers are available.
One molecular method, fluorescent in situ hybridization
(FISH), is playing an expanded role in the diagnosis of neoplasms
from a variety of cytologic samples including aspiration biopsies.
While much of the interest with FISH has been in finding added,
deleted, or translocated chromosomes as markers for urothelial
carcinoma detection, there are now a variety of relatively or very
specific chromosome abnormalities found in soft tissue and
other tumors that may be identifiable by FISH. Chromosomal
abnormalities have been detected in tumors from FNAs using
FISH and chromosome-specific probes.31,69,75 This method has
also been used to quantitate the neu oncogene in transformed
breast epithelial cells.76 For molecular diagnostic methods to be
effectively applied to aspirates or other cytologic samples, a ref-
erence laboratory or established medical center laboratory with
an expert and interested staff needs to be available. Molecular
diagnosis requires no special fixation or handling other than
those routinely employed for preserving cytologic or tissue sam-
ples. Material from paraffin-embedded cell blocks can also be
used for FISH and a variety of other molecular methods. Cyto-
spin preparations with adequate cellularity also work quite
effectively for FISH.51,54,77-79
Aspiration Technique
To be successful with an aspiration biopsy, it is important to
follow the preliminary steps listed here:
1. Review the history of the patient. Determine the
clinical problem and its relevance to the lesion to be
biopsied.
2. Determine whether the biopsy is justified.
3. Palpate the mass, attempting to determine its loca-
tion in relation to surrounding structures. Estimate its
depth. Decide on the optimal direction of the needle
to accomplish the aspiration biopsy.
A mass located deeply in tissue in usually best approached
perpendicularly to the skin surface. Small and superficially lying
tumors are best approached by penetrating the skin at or very
close to a horizontal plane, then feeling for the mass with the
needle tip.
4. The patient should be placed in a comfortable posi-
tion for the aspiration biopsy, but the mass must be
easily palpable and immobilized during the biopsy.
Step 4 is very important for head and neck lesions. The prom-
inence of an enlarged lymph node, or lump, may sometimes
depend on whether the patient is supine or erect. The sternoclei-
domastoid muscle bulk and its close proximity to the cervical
lymph nodes require positioning the patient such that the biopsy
needle passes through only a minimum of soft tissue and mus-
cle before reaching the target. Avoid aspirating a mass by travers-
ing the sternocleidomastoid muscle. It is painful and the needle
is likely to be plugged with fragments of muscle. The aspirate
smears may look like a good sample was obtained but it is all
skeletal muscle. For the aspiration of thyroid lesions, it is usually
helpful to place a small pillow under the patient's upper back,
extending the neck with the head tilted back. There is a groove
formed between the lateral border of the trachea and the medial
border of the sternocleidomastoid muscle. That is the area for
the aspiration of thyroid nodules within a plane perpendicular
to the transverse vertebral process. The transverse vertebral proc-
ess provides a reference point for deep-lying thyroid nodules.
The aspirating needle may penetrate to touch bone of the trans-
verse process, and then be withdrawn slightly. This should result
in the needle being within the thyroid nodule. Penetration of
the needle to the transverse process is not harmful or painful to
the patient. Remember to keep the needle in the perpendicular
plane as described above. Do not direct the needle either medi-
ally, which may result in penetration of the trachea, or laterally,
which could result in puncture of the carotid artery.
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