13
Respiratory Tract
solution of 15% sodium chloride and 20% propylene glycol.
After inhaling these vapors for approximately 20 minutes, a
patient usually produces copious satisfactory sputum.41
Bronchoscopy
The development of the rigid bronchoscope in the late nine-
teenth century by Gustav Killian formed the foundation of a
technology by which the mucosal surfaces of the bronchi could
be directly visualized and sampled for both tissue and cellular
evaluation. This technology has been furthered by the intro-
duction of flexible catheters advanced into the bronchi under
fluoroscopic control and perhaps even more importantly by
the development of the flexible fiberoptic bronchoscope. These
developments have been summarized by Walloch.42
Bronchial Aspirates and Washings
Introduction of the bronchoscope in the lower respiratory tract
enables the examiner to obtain specimens by means of a suction
apparatus that aspirates secretion. Washings from the visualized
areas may also be collected by instilling 3-5 mL of a balanced
salt solution through the bronchoscope and reaspiration of the
resulting material. Once the bronchoscope is removed, direct
smears may be made with immediate fixation in 95% ethyl
alcohol. The aspirates and washings may be treated in several
different ways. They may be centrifuged and smears prepared
from the cell buttons, they may be subjected to membrane fil-
ter preparation, or they may be centrifuged and the resulting
buttons embedded in paraffin for histologic sectioning. In our
experience, a judicious combination of direct smears and mem-
brane filter preparations of the aspirates and washings yields the
best diagnostic results.
Bronchial Brushings
The development of the flexible fiberoptic bronchoscope
has made it possible for the operator to view much smaller
bronchi of the lung than was formerly possible with the rigid
tube bronchoscope alone. With this apparatus, the examiner
may both visualize and brush a suspected lesion and submit
the resulting cytologic material for laboratory examination.
The techniques for preparation of cellular specimens from
the bronchial brush are similar to those used for bronchial
aspirates and washings.
Bronchoalveolar Lavage
BAL involves the infusion and reaspiration of a sterile saline
solution in distal segments of the lung via a fiberoptic bron-
choscope.43 This technique has been used in the therapy of such
diseases as pulmonary alveolar proteinosis, cystic fibrosis, pul-
monary alveolar microlithiasis, and asthma and has proved to
be of value in the diagnosis of pulmonary disease.43-47 Although
it has been used in the detection of lung cancer48,49 and the eval-
uation of interstitial lung disease,50 perhaps the most important
diagnostic application of BAL is for detecting opportunistic
infections in immunocompromised hosts.51-56
Fine-Needle Aspiration
The cytology of the respiratory tract has been revolutionized
by a combination of two factors: evolution of highly sophisti-
cated radiologic imaging techniques, making possible the pre-
cise visualization and localization of masses in the lungs, and
reintroduction of a sampling technique of such visualized
lesions by inserting a fine bore needle into them.57-59 In this pro-
cedure, a fine needle attached to a syringe is passed through the
chest wall or bronchial wall into the pulmonary mass visualized
by fluoroscopy, computed tomography, or bronchoscopy. The
aspirated cellular specimen is examined by conventional cellu-
lar techniques. The importance and usefulness of the techniques
are rapidly gaining wide recognition throughout the world, and
they have the potential of becoming the premiere tools for
evaluating pulmonary lesions.
Indications and Contraindications
Although some variation occurs amongst institutions in their
policies on indications for the performance of FNA, the follow-
ing ones are those most generally used and have been summa-
rized by Stitik60 and by Heaston and associates25:
(1)
Suspected lung cancer that is inoperable;
(2)
A solitary pulmonary mass suspected of being the
source of probable metastatic disease;
(3)
A solitary pulmonary nodule and known primary
malignancy outside the lung;
(4)
A patient who refuses exploratory thoracotomy for
suspected lung cancer;
(5)
Multiple pulmonary masses;
(6)
An undiagnosed pulmonary mass;
(7)
A suspected superior sulcus tumor;
(8)
A patient who fails to respond to appropriate
antituberculosis therapy;
(9)
A suspected infectious process, particularly in an
immunocompromised patient; and
(10) A patient who is suspected of having lung cancer
and who has produced five consecutive early
morning deep-cough specimens of sputum and
one bronchial brushing or washing that have been
negative for malignant tumor cells.
The last indication should be one on which all of the others
are dependent.
The contraindications for FNA include:
(1)
Patients who are debilitated or uncooperative or
who have an uncontrollable cough;
(2)
Patients who have a hemorrhagic diathesis, who
are undergoing anticoagulation therapy, or
who have a suspected vascular lesion or pulmonary
hypertension; and
(3)
Patients who have an echinococcus cyst.
Complications have included pneumothorax, hemoptysis,
and hemothorax.
The general technique of FNA came into use at our institu-
tion in the early 1970s. Among the total number of aspirates
examined from all body sites, 30% have been from the lung.
In the medical center's most current procedure, any patient
found to have a demonstrable radiographic abnormality in
the lung fields is a potential candidate for FNA. The deci-
sion about whether to proceed with the aspiration is based
on the level of suspicion that the visualized nodule or density
represents a cancer or an infectious process and on the mor-
phologic evidence provided by prior cytologic and histologic
specimens obtained from the respiratory tract. All aspirations
are performed by a radiologist using fluoroscopy or computed
tomography.
305
previous page 302 ComprehensiveCytopathology 1104p 2008 read online next page 304 ComprehensiveCytopathology 1104p 2008 read online Home Toggle text on/off