13
Respiratory Tract
Fig. 13.43 Plant cells. Such cells may mimic atypical squamous cells
because of nuclear hyperchromasia, and sharp cytoplasmic borders.
Careful examination, however, reveals the presence of cell walls. Sputum
(Papanicolaou x OI).
of pulmonary infectious disease. Rather, it is limited to a pres-
entation of those organisms that a cytologist is most likely to
encounter (Table 13.4). The major emphasis is on cytologic
detection of some mycoses and several miscellaneous parasitic
organisms frequently associated with opportunistic infection.
The need for close cooperation among the cytology laboratory,
the clinical microbiology laboratory, and the patient's physician
is implicit in this discussion.161 Special stains for bacteria, acid-
fast bacteria, fungi, and parasites should be used when appro-
priate (Table 13.5).162 Viral infections may produce changes of
diagnostic significance in squamous, bronchial, bronchiolar,
and alveolar epithelial cells.
Among those patients with suspected respiratory infections,
a new and unique group has emerged consisting of those who
have preexisting diseases of various etiologies and who have
developed new respiratory signs and symptoms demanding
evaluation and therapy. These patients have histories involv-
ing many disease backgrounds, but frequently encountered are
those patients who have established pulmonary or extrapulmo-
nary cancer and who are under various programs of radiation
therapy and chemotherapy; patients who have primary immune
deficiencies; and patients who have immune responses sup-
pressed by drugs. In the last two groups are renal allograft recipi-
ents and the alarmingly increasing population of patients with
acquired immunodeficiency syndrome (AIDS). When a patient
with one of these histories develops a problem in the lungs, it
can be related to any one of the following factors: recurrence of
neoplasm, a new disease unrelated to the preexisting one, lung
changes induced by the chemotherapeutic agents, or opportunis-
tic lung infection with one or more organisms. Any one of these
disease states can be life-threatening to the patient and must
immediately be correctly diagnosed and treated. The role of
the cytology laboratory in the diagnosis of opportunistic infec-
tions of the lower respiratory tract merits major consideration,
because a number of these infectious agents readily lend them-
selves to detection and correct diagnosis by cytologic methods
and principles.26,165-170
Table 13.4 Infectious Organisms Detectable in Cytologic Specimens from
the Lung
Viruses
Herpes simplex
Herpes zoster
Cytomegalovirus
Adenovirus
Measles virus
Parainfluenza virus
Respiratory syncytial virus
Bacteria
Gram-positive and Gram-negative
Staphylococcus aureus
Pseudom onas aeruginosa
Legionella
spp.
Acid-fast
M ycobacterium tuberculosis
M ycobacterium avium
and
M. intracellulare
Fungi
Actinom yces bovis
N ocardia asteroides
Blastomyces derm atitidis
Cryptococcus neoform ans
H istoplasm a capsulatum
C andida albicans
Paracoccidioides brasiliensis
Coccidioides im m itis
Aspergillus fum ig atus
Aspergillus niger
Phycomycetes
Parasites
Pneum ocystis carinii
Toxoplasm a g ond ii
Strongyloides stercoralis
D irofilaria im m itis
Echinococcus
Parag onim us kellicotti
Parag onim us w esterm ani
Cryptosporidium
Viral infections
In a review, Rosenthal placed the role of cytology in the diag-
nosis of viral infections of the lung into appropriate perspective
when she noted:
Definite viral diagnosis is made by viral culture, DNA probes,
immunocytochemistry or other specific diagnostic techniques.
However, the changes appreciated in the specimens stained by
the Papanicolaou technique can provide a rapid preliminary
319
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