PART TWO
Diagnostic Cytology
Fig. 13.12 Multinucleated ciliated bronchial epithelial cell.
Bronchial
brushing (Papanicolaou x OI).
Fig. 13.13 Hyperplastic bronchial epithelium
from a patient with
asthma. Note uniformity of nuclei, cilia, and terminal bars. Sputum
(Papanicolaou x OI).
individual cells, although chromatin and nucleolar structures
remain relatively unremarkable. Nuclear detail may at times be
obscured because of the thickness of the tissue fragment. Vari-
ous numbers of vacuolated mucus cells may also be present in
these fragments. The key to their benignity is to be found in the
finely granular chromatin pattern, regular uniform nucleoli, and
the presence of cilia (Fig. 13.13).
Hyperplasia o f Type II Pneumocytes
In the presence of insult, type II pneumocytes may enlarge, pro-
liferate, and produce differential diagnostic problems. In such
circumstances, they may be present either as single cells or as
small papillary tissue fragments composed of enlarged cells with
prominent nucleoli. Hyperdistended vacuoles may be present
in the cytoplasm. Differential diagnosis of such cells becomes
a rather formidable problem of determining whether the cells
are coming from one of the benign disease processes, such as
tuberculosis,
pulmonary fibrosis, thermal injury, thrombo-
embolism with or without pulmonary infarction, anthracosis,
interstitial pneumonia, systemic lupus erythematosus, acute
toxic
alveolar
damage,
oxygen
toxicity,
and
organizing
pneumonia, or whether they are actually derived from bronchi-
oloalveolar carcinoma.88-92
Table 13.1
A Profile of Signs and Diseases in 43 Patients without Cancer
but with Cytologic Diagnoses Suspicious for Malignancy
Disease
category
Number
of patients
Percentage of
patients
Pneumonia
17
39.5
Smoking history
9
20.9
Hemoptysis
7
16.3
Chronic obstructive
pulmonary disease
7
16.3
Granulomatous
disease
7
16.3
Chronic bronchitis
6
14.0
Abscess
4
9.3
Mass
4
9.3
Infarct
2
4.6
Other
8
18.6
Reproduced with permission from Johnston WW. Cytologic correlations. In: Dail
DH, Hammar SP (eds)
Pulmonary Pathology.
New York: Springer-Verlag, 1987.
Pulmonary infarcts are cited in the literature as being par-
ticularly prone to giving rise to such cells in sputum,93 how-
ever, in our experience, they are most frequently encountered in
association with pneumonias of various forms and etiologies
(Table 13.1). Frable and Johnston23 and Johnston and Frable30,31
have emphasized a diagnostic distinction between the poorly
preserved cell clusters associated with infarcts and the well-
preserved cells forming ball-like clusters without molding but
with deep depth of focus, which are originating in bronchi-
oloalveolar carcinoma. Silverman and associates reported one
case in which a pulmonary infarct was diagnosed by FNA.94
Hyperplastic type II pneumocytes in FNAs can constitute one
of the most dangerous of diagnostic pitfalls. Insistence on a
specimen of high cellularity for positive cancer diagnosis is a
major factor in avoiding such an error. Figures 13.14 and 13.15
illustrate the atypical cell clusters from two separate patients
who, on the basis of cytologic study, were suspected of having
bronchioloalveolar carcinoma. Findings at autopsy in the sec-
ond case revealed chronic organizing pneumonia with hyper-
plasia of type II pneumocytes (Fig. 13.16). Other examples of
hyperplasia of type II pneumocytes are depicted in Figs. 13.17
to 13.20. A special situation of hyperplasia of type II pneumo-
cytes in response to chemotherapy is discussed in the section
"Epithelial Cellular Changes Following Radiation Therapy,
Chemotherapy, and Toxic Chemicals."
Squamous Metaplasia and Reserve Cell Hyperplasia
The term
metaplasia
is used to define a morphologic entity in
which one differentiated cell type ordinarily composing a
part, covering, or lining of a tissue is replaced by a differenti-
ated cell of another type. Squamous metaplasia, when used
in reference to the lung, describes the replacement of the cili-
ated pseudostratified bronchial epithelium normally lining the
trachea and bronchi by a truly stratified and flattened epithe-
lium that resembles squamous epithelium. Although squamous
metaplasia probably represents an attempt of the host to repair
310
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