13
Respiratory Tract
Fig. 13.55 Mucormycosis. Characteristic branching, ribbon-like hyphal
fragments without obvious septa. Bronchial brushing (Papanicolaou x OI).
fold and wrinkle gives them a ribbon-like appearance. Because
of this as well as their hyaline nature, they may be easily misin-
terpreted as fragments of plant fibers or other foreign material
(Fig. 13.55).219
Other Fungi
Other fungi that have been implicated in lung infections include
Torulopsis glabrata,
a small yeast-like fungus;
Fusarium
spp., with
hyphae resembling those of
Aspergillus; Trichosporon
spp., with
small yeast-like cells, septate hyphae, and arthrospores;
Geotri-
chum candidum
, with septate hyphae, spheric cells, and rectangu-
lar arthrospores;
Penicillium
spp., with small round, nonbudding
yeast-like cells with transverse septa;
Chrysosporium parvum
var.
crescens
, with its very large spheric adiaconidia, the etiologic
agent of the pulmonary mycosis adiaspiromycosis;
Curvularia
spp., with pigmented hyphae;
Sporothrix schenckii,220
with its
small ovoid to cigar-shaped yeast-like cells;
Petriellidium bovdii,
with septate branching hyphae;193
Fonsecaea pedrosoi,
cultured
from an FNA of pulmonary phaeohyphoycosis;221
Penicillium
marneffei
in BAL;222
Actinomyces
spp.;223 and
Alternaria
spp.224
Parasitic infections
A growing number of parasites are being diagnosed in respiratory
material. The two most frequent ones,
Pneumocystis carinii
and
Strongyloides stercoralis,
are emphasized in this section.225-227
Pneumocystis carinii
Pneumonia
Before 1960, the organism
P. carinii
was little more than an
academic curiosity. It was rarely diagnosed clinically and, when
seen at autopsy, was found to be present almost exclusively in
debilitated premature infants.
Pneumocystis carinii
pneumonia
has been increasing in incidence, however, and is now recog-
nized as potentially occurring in any situation of impaired
immune response.228 More particularly, it is observed in infants
who are premature or debilitated, in patients who have immu-
nologic disorders and immunoglobulin defects, and in those
undergoing therapy with corticosteroids and chemotherapy.
The infection has been found with high frequency in patients
who have received renal allografts. The infection has also been
described as a complication in AIDS.229-238 The introduction of
effective therapeutic drugs has markedly increased the clinical
importance of a diagnosis.239,240
Cytology
On Papanicolaou-stained material, the organisms may be dif-
ficult to identify, because their staining may be quite variable
and faint. A most typical presentation on the smear is a mass
of partially eosinophilic amorphous material. Within this mass
may be a suggestion of small superimposed circlets. Although
this presentation may or may not be diagnostic for
Pneumocystis,
such material should raise an immediate suspicion of its pres-
ence, and the material should be further evaluated by special
stains. In such a situation, one would decolorize this slide and
restain with methenamine silver. This procedure immediately
brings out the diagnostic features of these organisms. On meth-
enamine silver stains, the organism is seen mainly as a spheric
cyst measuring 6-8 pm in diameter, or approximately the diam-
eter of an erythrocyte (Fig. 13.56). Certain variations of this form
can be seen: The organism can be cup shaped, crescent shaped,
or crinkled. Depending on which surface of the organism is
exposed to view, small interior structures can be seen to take
the forms of rings, dots, or commas. Some laboratories prefer
to use a Giemsa stain or toluidine blue for identification of this
organism.241 With these stains, one is able to identify as many as
eight trophozoites occurring within the cyst. These structures are
about 0.5-1.0 pm in diameter. They are easily overlooked and
may be confused with granules or cell fragments.
Zapata and associates reviewed 2984 specimens of BAL fluid
to which both Papanicolaou and methenamine silver stains
had been applied.
Pneumocystis
organisms were identified in
both stains in 103 specimens (88.7% of total positive BALs);
on Papanicolaou-stained specimens only in 11 specimens (9.4%
of total positive BALs); and on methenamine-stained specimens
only in 2 specimens (1.7% of total positive BALs).242
A renewed interest has taken place in the initial recognition of
P. carinii
in smears stained by the Papanicolaou method. Greaves
and Strigle have described these organisms in such smears as
appearing in the form of casts of alveoli.232 These casts are com-
posed of masses of organisms packed together with a smooth
border around the periphery of the masses, representing the
molding induced by the alveolar walls. Tinctorial characteristics
of these masses vary from eosinophilic to cyanophilic. In our
experience, casts may be seen in sputum, bronchial material,
BALs, and FNAs. They may be extremely numerous in the pres-
ence of massive infection such as that in patients with AIDS and
are conclusively diagnostic for P
carinii
(Figs 13.56 to 13.58).
Ghali and associates have reported apple-green fluorescence of
these masses in Papanicolaou-stained smears when exposed to
ultraviolet light.231 Chandra and associates have reported the
Diff-Quik stain to be positive in 76% of cases.243
In the literature, one can find reports of success in diagnos-
ing this organism in sputum, tracheal aspirates,233 washings
from the hypopharynx and bronchus, bronchial brushings,217
BAL,72,229,235,244 and FNA.31 Among these, BAL has clearly emerged
as the one most likely to yield organisms.53 Organisms easily
confused with
Pneumocystis
are the small budding yeasts, nota-
bly
H. capsulatum, Candida
spp., and
Saccharomyces.
The most
reliable distinguishing characteristic is the presence of budding.
The bronchial brushing illustrated in Fig. 13.57 is from a 27-
year-old man who was admitted for evaluation of high fever
and bilateral pulmonary infiltrates. A typical alveolar cast com-
posed of
Pneumocystis
organisms is depicted. The patient was
diagnosed as having AIDS and died 2 weeks later. Figure 13.58
shows a similar cast at higher magnification. The cysts are clearly
visible.
327
previous page 324 ComprehensiveCytopathology 1104p 2008 read online next page 326 ComprehensiveCytopathology 1104p 2008 read online Home Toggle text on/off