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1248 AJR:187, November 2006
AJR 2006; 187:1248–1252
0361–803X/06/1875–1248
© American Roentgen Ray Society
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Souza et al.
CT of
Untreated
Pulmonary
Paracoccidio
idomycosis
Chest Imaging • Original Research
High-Resolution CT Findings of
77 Patients with Untreated
Pulmonary Paracoccidioidomycosis
Arthur Soares Souza, Jr.
1
Emerson Leandro Gasparetto
2
Taisa Davaus
3
Dante Luiz Escuissato
3
Edson Marchiori
2
Souza AS Jr, Gasparetto EL, Davaus T,
Escuissato D, Marchiori E
Keywords: chest, high-resolution CT, infectious diseases,
lung diseases, pulmonary paracoccidioidomycosis
DOI:10.2214/AJR.05.1065
Received June 21, 2005; accepted after revision
September 29, 2005.
1
Faculty of Medicine of São José do Rio Preto, São José do
Rio Preto, São Paulo, Brazil.
2
University of Rio de Janeiro, Rio de Janeiro, Brazil.
Address correspondence to E. L. Gasparetto, R Fernando
Amaro 98, ap 61, 80050-020 Curitiba, PR, Brazil.
3
University of Paraná, Curitiba, Paraná, Brazil.
OBJECTIVE. The objective of our study was to describe the high-resolution CT findings of
77 patients with pulmonary paracoccidioidomycosis (PCM) who had not yet been treated for PCM.
MATERIALS AND METHODS. The high-resolution CT scans of 77 consecutive pa-
tients with proven pulmonary PCM were reviewed by two chest radiologists, and decisions re-
garding the CT findings were reached by consensus. Seventy-one of the patients were men and
six were women, with an average age of 49 years. The criteria for interpretation of the high-
resolution CT scans are defined in the Fleischner Society’s Glossary of Terms.
RESULTS. The most frequent high-resolution CT findings were ground-glass attenuation
areas (58.4%), small centrilobular nodules (45.5%), cavitated nodules (42.9%), large nodules
(41.6%), parenchymal bands (33.8%), areas of cicatricial emphysema (33.8%), interlobular
septal thickening (31.2%), and architectural distortion (29.9%). Most of these high-resolution
CT findings predominated at the periphery (53%) and posterior (88%) regions involving all
lung zones, with discrete predominance in the middle zones (35%).
CONCLUSION. The high-resolution CT findings of patients with pulmonary PCM who
have not yet been treated consist of ground-glass attenuation areas associated with small cen-
trilobular nodules, cavitated nodules, large nodules, parenchymal bands, and areas of cicatricial
emphysema. These abnormalities are usually distributed in the posterior and peripheral regions
of the lungs, with discrete predominance in the middle lung zones.
aracoccidioidomycosis (PCM) is
the most frequent endemic sys-
temic mycosis in Latin America,
particularly in Brazil, Argentina,
Colombia, and Venezuela [1, 2]. The infec-
tion is caused by Paracoccidioides brasilien-
sis organisms, a dimorphic fungus that grows
as budding yeast in tissue and as yeast or mold
in culture medium. The disease is acquired by
inhalation of infectious particles that reach
the lungs and develop the primary infection
[3]. Initially, the disease presents with no sig-
nificant symptoms, but some cases may
progress to severe pulmonary involvement [4,
5]. The lungs are the main target organ of P.
brasiliensis organisms, and infection of the
lungs is the leading cause of morbidity and
mortality in patients with PCM [1, 6, 7]. Ac-
tive pulmonary involvement and residual fi-
brotic lesions have been reported in 80% and
60% of patients with PCM, respectively [6].
High-resolution CT is frequently performed
in the investigation of pulmonary infections,
including PCM [4, 7–10]. However, the few
studies that have investigated the high-resolu-
tion CT findings of PCM included patients
who had been treated for PCM before the CT
scans were obtained [4, 7, 8]. Those studies
showed that interlobular septal thickening,
ground-glass opacities, nodules, peribroncho-
vascular interstitial thickening, and traction
bronchiectasis were the most common high-
resolution CT features of PCM [4, 7]. How-
ever, there are no studies, to our knowledge,
that have investigated the high-resolution CT
findings of patients with pulmonary PCM who
had not been treated for PCM before undergo-
ing scanning. Recognition of CT patterns asso-
ciated with pulmonary PCM could help in the
early diagnosis of PCM and in the institution of
a specific treatment for PCM, so lung damage
caused by the disease can be avoided.
The aim of this study was to present the
high-resolution CT findings of 77 patients
with pulmonary PCM who had not been
treated previously for PCM.
Materials and Methods
This study retrospectively analyzed the high-reso-
lution CT scans of 77 consecutive patients with
P
CT of Untreated Pulmonary Paracoccidioidomycosis
AJR:187, November 2006 1249
proven pulmonary PCM who underwent high-resolu-
tion CT at our hospitals. None of the patients had re-
ceived any modality of treatment for pulmonary
PCM before undergoing CT. There were 71 (92.2%)
men and six (7.8%) women who ranged in age from
29 to 75 years (median, 49 years). All patients were
symptomatic, usually presenting with chronic cough,
slowly progressive dyspnea, and a low fever. The
time that had elapsed between the onset of symptoms
and diagnosis of PCM infection ranged from 1 to 12
weeks (median, 3 weeks; SD, 3.54 weeks). The diag-
nosis of P. brasiliensis infection was made at bron-
choalveolar lavage (n = 28), bronchial or transbron-
chial biopsy (n = 24), or surgical lung biopsy (n = 25)
(or a combination of these techniques).
The CT scans were obtained at end-inspira-
tion using a 1- or 2-mm collimation at 10-mm in-
tervals and were reconstructed with a high-
spatial-frequency algorithm (Somaton ART,
Siemens Medical Solutions; and Xvision,
Toshiba). The images were photographed at me-
diastinal (width, 350–450 H; level, 15–25 H)
and lung (width, 1,400–1,600 H; level, –600 to
800 H) window settings.
The films were studied by two chest radiolo-
gists, and decisions regarding the findings were
reached by consensus. The following high-reso-
lution CT features were analyzed: air-space con-
solidation, ground-glass attenuation, nodules
(characterized as large [> 10 mm]; small [< 10
mm] centrilobular; or random), cavitated nod-
ules, “reversed halo sign,” tree-in-bud opacities,
interlobular or intralobular septal thickening,
peribronchovascular or bronchial wall thicken-
ing, bronchiectasis, parenchymal bands, architec-
tural distortion, cysts, and areas of low attenua-
tion (cicatricial emphysema). Criteria for these
findings are defined in the Fleischner Society’s
Glossary of Terms [9]. Each one of these findings
was analyzed concerning its distribution in the
lung parenchyma (central, peripheral, or both; an-
terior, posterior, or both; and upper, middle, or
lower zone or a combination of zones). Lymph
node enlargement, pleural effusions, and any
other lung abnormalities were also studied.
Fig. 1—High-resolution CT scan at level of inferior lobes shows interlobular septal
thickening and multiple small centrilobular nodules, some of which have tree-in-bud
pattern, in 35-year-old man with pulmonary paracoccidioidomycosis.
Fig. 2—High-resolution CT scan at level of carina shows multiple nodules and
masses in 61-year-old man with pulmonary paracoccidioidomycosis. Associated
cavitated mass is seen in left lung.
Fig. 3—High-resolution CT scan at level of carina shows subsegmental multifocal
consolidations in 42-year-old man with pulmonary paracoccidioidomycosis.
Fig. 4—High-resolution CT scan at level of inferior lobes shows diffuse ground-glass
opacities associated with areas of reduced parenchyma attenuation in 37-year-old
man with pulmonary paracoccidioidomycosis. In addition, irregular interlobular
septal thickening with architectural distortion is identified.
Souza et al.
1250 AJR:187, November 2006
Results
All the patients in this study had abnormal
findings on high-resolution CT scans. The most
frequent findings were ground-glass attenua-
tion areas (58.4%, n = 45), small centrilobular
nodules (45.5%, n = 35), cavitated nodules
(42.9%, n = 33), large nodules (41.6%, n =32),
parenchymal bands (33.8%, n = 26), areas of
cicatricial emphysema (33.8%, n = 26), inter-
lobular septal thickening (31.2%, n = 24), and
architectural distortion (29.9%, n =23)
(Figs. 1–7). Mediastinal lymph node enlarge-
ment was seen in 10 patients and pleural effu-
sions in two cases. The most common high-res-
olution CT findings and their distribution are
detailed in Table 1.
Patients with pulmonary PCM frequently
present with several high-resolution CT fea-
tures, but a predominant high-resolution CT
abnormality was defined in each case. The
most frequent predominant findings were
ground-glass attenuation areas (32.5%,
n = 25), small centrilobular nodules (15.6%,
n = 12), large nodules (15.6%, n =12), and
the reversed halo sign (6.5%, n =5).
Abnormal high-resolution CT findings
were predominant in the periphery of the
lungs in 53% of the cases, in the central and
peripheral regions in 29.4%, and in the central
lung regions in 17.6% of the patients. Con-
cerning the anterior and posterior lung zones,
most of the abnormalities predominated pos-
teriorly (88%, n = 15), and the remaining two
(12%) involved similar amounts of anterior
and posterior lung regions. Finally, in 35% of
Fig. 5—High-resolution CT scan at inferior pulmonary veins shows multifocal
ground-glass attenuation areas, nodules with halo sign, and “reversed halo sign” at
left lung in 55-year-old man with pulmonary paracoccidioidomycosis.
Fig. 6—High-resolution CT scan at level of inferior pulmonary veins shows random
nodules with halo sign, cavitated nodules, and cavitated mass at left inferior lobe in
57-year-old man with pulmonary paracoccidioidomycosis.
the cases, the features predominated in the
middle lung zones; in 23%, in the inferior;
and in 6%, in the superior lung regions. The
superior and middle lung zones were simi-
larly involved in 18% of the cases, as well as
the middle and inferior lung areas (18%).
Discussion
PCM, or South American blastomycosis,
is an important systemic mycosis in Latin
America [2]. The most severe endemic areas
of PCM in the world are in the subtropical
regions of Brazil. In those endemic areas,
PCM is estimated to affect up to 10% of the
population, being particularly prevalent in
farm workers [3, 4]. The etiologic agent, P.
brasiliensis, is an aerobic dimorphic fungus
with an unknown habitat [6]. The disease is
acquired by inhalation of infective particles
that cause a self-limited inflammatory pa-
renchymal lung infection [5]. The initial le-
sion is similar to the primary complex of tu-
berculosis, and it is controlled by natural
defensive mechanisms or it progresses to
symptomatic disease. Following this pri-
mary complex, the fungus can spread by
lymphatic or blood circulation to the kid-
neys, spleen, liver, bone, adrenal glands, and
CNS [2]. The lung is the organ most com-
monly affected (50–100%) and is the site of
Fig. 7—High-resolution
CT scan at level of
inferior lobes shows
multiple ground-glass
attenuation balls,
“reversed halo sign,”
and cavitated nodule
with halo sign at
posterior region of right
lung in 48-year-old man
with pulmonary
paracoccidioidomycosis.
CT of Untreated Pulmonary Paracoccidioidomycosis
AJR:187, November 2006 1251
lesions associated with the acute and chronic
forms of infection [2, 6].
Few studies have aimed to present the
high-resolution CT findings of patients with
pulmonary PCM [4, 7, 8]. In addition, the
authors of those studies included in their se-
ries patients who had been treated for PCM
infection before the CT investigation. Muniz
et al. [4] analyzed 30 cases of pulmonary
PCM, including 16 patients who underwent
CT after treatment for PCM had been initi-
ated. The most common high-resolution CT
findings in that study included interlobular
septal thickening (96.7%), ground-glass
opacities (66.7%), nodules (60%), areas of
cicatricial emphysema (56.7%), and bron-
chial wall thickening (46.7%). Funari et al.
[7] studied the high-resolution CT findings
of the largest series of patients with pulmo-
nary PCM, but those authors included only
four patients who had not been treated for
PCM infection before undergoing CT. The
most common high-resolution CT features
in that study were interlobular septal thick-
ening (88%), nodular opacities (83%), trac-
tion bronchiectasis (83%), peribronchovas-
cular interstitial thickening (78%), areas of
cicatricial emphysema (68%), and centrilob-
ular nodular opacities (63%). These findings
showed a predominant bilateral and sym-
metric distribution, affecting all lung zones.
The most frequent high-resolution CT
findings in the present study were ground-
glass attenuation areas (58.4%, n = 45), small
centrilobular nodules (45.5%, n = 35), cavi-
tated nodules (42.9%, n = 33), large nodules
(41.6%, n = 32), parenchymal bands (33.8%,
n = 26), areas of cicatricial emphysema
(33.8%, n = 26), interlobular septal thicken-
ing (31.2%, n = 24), and architectural distor-
tion (29.9%, n = 23). Most of these high-res-
olution CT findings predominated at the
periphery (53%) and posterior (88%) regions
involving all lung zones, with discrete pre-
dominance in the middle zones (35%). Fi-
nally, the most frequent predominant findings
were ground-glass attenuation areas (32.5%),
small centrilobular nodules (15.6%), and
large nodules (15.6%). These patterns and
their distribution are different from those re-
ported by Muniz et al. [4] and Funari et al. [7].
These differences can probably be attributed
to two factors. First, those authors included in
their series patients who had been treated for
PCM infection before undergoing CT. The re-
ticular pattern, mainly interlobular septal
thickening, that was frequently seen in those
studies may be associated with the chronic
form of infection and sequelae, thus explain-
ing why those findings were not predominant
in our series. Second, although both of the
other studies analyzed the high-resolution CT
scans based on criteria defined in the
Fleischner Society’s Glossary of Terms [9],
our study protocol was more detailed, includ-
ing findings that were recommended by the
glossary of terms but were not considered by
the authors of the other studies.
Funari et al. [7] compared the high-resolu-
tion CT findings of two groups of patients in
their series: those who received up to 3
months of treatment (n = 16) and those who
received more than 3 months of treatment
(n = 25). Although this could correct the bias
of their study, which included treated and
nontreated patients, Funari et al. added four
patients who had not received treatment be-
fore CT to the group of patients who had re-
ceived up to 3 months of treatment. The com-
parison was performed using Fisher’s exact
test, and p values less than 0.05 were consid-
ered statistically significant. The patients who
had received less than 3 months of treatment
were more likely to present with areas of
ground-glass attenuation (p
= 0.02), air-space
consolidations (p < 0.01), and cavitations
(p < 0.01). Comparing our results with those
of that study [7], we observe that our findings
are more similar to those seen in the group of
patients who had received up to 3 months of
treatment than those seen in the group who
had received more than 3 months of treat-
ment. Parenchymal bands and architectural
distortion, although common in our study,
were not predominant features, probably indi-
cating that these findings are more frequently
representative of chronic pulmonary PCM.
In conclusion, our study shows that the
most frequent high-resolution CT findings in
patients with pulmonary PCM who had not
yet been treated for PCM infection include
ground-glass attenuation areas, small centri-
lobular nodules, cavitated nodules, large
nodules, parenchymal bands, and areas of
cicatricial emphysema. Most of these high-
TABLE 1: Summary of the Most Common High-Resolution CT Findings in Patients with Pulmonary
Paracoccidioidomycosis and Their Distribution in the Lungs
High-Resolution CT Finding
No. of
Patients
Distribution of the High-Resolution CT Findings
Central Periphery
Central and
Periphery Upper Middle Lower Anterior Posterior
Ground-glass attenuation 45 1 18 26 35 41 36 35 42
Small centrilobular nodules 35 — 19 16 28 33 23 30 34
Cavitated nodules 33 2 25 6 16 22 21 9 28
Large nodules 32 — 18 14 20 29 22 19 32
Parenchymal bands 26 1 24 1 5 14 16 8 26
Areas of cicatricial emphysema 26 — — 26 22 17 18 16 19
Interlobular septal thickening 24 — 14 10 15 17 18 13 22
Architectural distortion 23 3 10 10 12 19 8 9 22
Bronchial wall thickening 16 6 5 5 11 12 9 5 14
Air-space opacities 16 1 9 6 10 14 6 8 15
“Reversed halo sign” 15 1 11 3 7 12 11 10 10
Intralobular septal thickening 11 — 7 4 6 6 10 6 11
Tree-in-bud opacities 11 — 4 7 7 9 7 7 10
Note—Dash (—) indicates 0 cases.
Souza et al.
1252 AJR:187, November 2006
resolution CT findings predominated at the
periphery and posterior regions, involving
mainly the middle lung zones. In addition,
ground-glass attenuation areas, small centri-
lobular nodules, and large nodules were the
most common predominant high-resolution
CT findings in our series. Therefore, we be-
lieve that, in the appropriate geographic ar-
eas, the diagnosis of PCM should be sug-
gested in patients presenting with these
pulmonary CT features so that therapy for
the infection can be initiated and, thus, lung
damage can be avoided.
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