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1712
http://journals.tubitak.gov.tr/medical/
Turkish Journal of Medical Sciences
Turk J Med Sci
(2016) 46: 1712-1718
© TÜBİTAK
doi:10.3906/sag-1508-114
Cryptogenic organizing pneumonia: clinical and radiological features,
treatment outcomes of 17 patients, and review of the literature
Elif Yelda NİKSARLIOĞLU*, Gülcihan Zehra ÖZKAN, Nur Dilek BAKAN, Sibel YURT, Lütfiye KILIÇ, Güngör ÇAMSARI
Department of Chest Diseases, Yedikule Chest Diseases and oracic Surgery Training and Research Hospital, İstanbul, Turkey
* Correspondence: eyelda2003@yahoo.com
1. Introduction
Cryptogenic organizing pneumonia (COP) is a disease
of unknown etiology, which is characterized by
granulation tissue obstructing the alveolar ducts and
chronic inammation occurring in contiguous alveoli
(1). Collagen vascular diseases, drugs, malignancies,
and aspiration can all lead to the clinical diagnosis of
secondary organizing pneumonia; the term COP, however,
is used for cases of unknown etiology. COP is included in
the class of idiopathic interstitial pneumonia in the joint
statement of the American oracic Society (ATS) and the
European Respiratory Society (ERS), which was revised in
2013 (2). Although there are various publications on the
clinical ndings, radiological ndings, and treatment of
this disease, most of the papers are case reports (3–5). In
the present study, we present the clinical and radiological
ndings, as well as the treatment and follow-up outcomes,
of 17 patients diagnosed with COP.
2. Materials and methods
A total of 17 patients who attended the Yedikule Training
and Research Hospital for Chest Diseases and oracic
Surgery and were subsequently diagnosed with COP were
retrospectively evaluated. Diagnosis of COP was made by
bronchoscopic transbronchial biopsy (TBB), video-assisted
thoracoscopy (VATS), and open lung biopsy (OLB). All
patients were followed between October 2006 and April
2014 at the hospital. ose with conrmed diseases that
might cause organizing pneumonia were excluded from
the study. e demographic data, symptoms, radiological
ndings, diagnostic methods, and treatment regimen for
each patient were collected from the patients’ hospital
records.
2.1. Statistical analysis
Descriptive statistics only are given. Statistical comparisons
were not performed because of the limited number of cases.
Continuous variables are presented as mean and standard
deviation, whereas categorical variables are presented as a
number and a percentage.
3. Results
Seventeen COP patients (49.8 ± 10.4 years; range: 29–
69) were retrospectively evaluated. Seven (41.2%) of the
patients were men. e demographic data are shown in
Background/aim: We evaluated patients with cryptogenic organizing pneumonia (COP) who attended our clinic.
Materials and methods: We retrospectively investigated the clinical and radiological ndings, diagnostic methods, treatment, and
follow-up outcomes of 17 patients who had been histopathologically diagnosed with COP.
Results: e mean age of the patients was 49.8 ± 10.4 years. e most common symptom was cough (n = 15; 88.2%) and the most
common radiological nding (n = 10) was consolidation in the inferior lobes on thoracic computed tomography. e diagnosis of COP
was made by open lung biopsy in 11 (64.7%) patients, transbronchial biopsy in 5 (29.4%), and video-assisted thoracoscopic surgery
biopsy in 1 (5.9%). e mean follow-up period was 28.7 ± 25.0 (range: 3–85) months. Twelve patients received oral corticosteroid
therapy and seven of them improved without any brotic changes. One patient refused treatment; a chest radiography of that patient
was found to be normal at the end of the 20-month follow-up period. ree patients received no other therapy, as the lesion had been
completely excised.
Conclusion: Common symptoms included cough and dyspnea, while the main radiological presentation of COP was consolidation.
Corticosteroids are a good treatment option in general, but relapse may occur.
Key words: Cryptogenic organizing pneumonia, follow-up, radiology, symptom, treatment
Received: 25.08.2015 Accepted/Published Online: 04.03.2016 Final Version: 20.12.2016
Research Article
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NİKSARLIOĞLU et al. / Turk J Med Sci
Table 1. e mean duration of cough, which was the most
common symptom, was 54 ± 30 days. Of those patients
with pleuritic chest pain, one had a pleural eusion and
four had peripheral lesions. Pulmonary function tests
(PFTs) were performed in 14 patients: one patient had
an obstructive pattern and ve patients had restrictive
patterns, whereas PFTs were considered to be normal in
the others (Table 2).
e most common radiological nding was
consolidation in the le (n = 10) and right (n = 6) lower
lobes (Figure; Table 3). While lesions were present in
more than one segment on computed tomography/high-
resolution computed tomography (CT/HRCT) in nine
(53%) patients, only one segment was involved in the
remaining eight patients. One of the patients had a mass
lesion on thorax CT with minimal pleural eusion on the
Table 1. General characteristics and symptoms of the patients.
Variables Results
Number of patients 17
Age, years 49.8 ± 10.4 (range: 29–69)
Sex (female) 10 (58.8)
Smoking 6 (35.3)
Current smoker 2 (12.5)
Ex-smoker 4 (25)
Cough 15 (88.2)
Dyspnea on exertion 8 (47.1)
Weakness 6 (35.3)
Pleuritic chest pain 6 (35.3)
Fever 4 (23.5)
Hemoptysis, 2 (12.5)
Comorbidity* 3 (18.5)
Data are presented as n (%), *: Vertigo, asthma, obstructive sleep apnea syndrome.
Table 2. Laboratory ndings and pulmonary function tests of patients.
Findings Valu e
Hemoglobin, g/dL 12.8 ± 2.3
Leukocyte count, /mm38488 ± 2077
Platelet count, /mm3313,700 ± 9150
Eosinophil, % 3.3 ± 1.8
Sedimentation, mm/h 45.8 ± 40.0
CRP, mg/L 5.9 ± 5.3
FEV1 (L)* 2.7 ± 0.8
FEV1 (%, predicted)* 88.1 ± 16.3
FVC (L)* 3.0 ± 0.9
FVC (% predicted)* 86.4 ± 18.6
FEV1/FVC* 84.2 ± 10.1
DLCO (mL/min/mmHg)** 36 ± 35
DLCO (% predicted)** 69.6 ± 5.5
Data are presented as mean ± standard deviation, * n = 13 cases; ** n = 3 cases, FEV1:
forced expiratory volume in 1 s, FVC: forced vital capacity, DLCO: diusion capacity of
carbon monoxide.
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NİKSARLIOĞLU et al. / Turk J Med Sci
same side. is patient had undergone positron emission
tomography (PET-CT) scanning at another center due to a
suspicion of malignancy before admission to our hospital,
and the maximum standardized uptake value (SUVmax)
was reported to be 10. In a second patient with a mass
lesion, PET-CT scans revealed no FDG uptake. e third
patient with a mass on thoracic CT was not evaluated with
PET-CT scan.
Fieen patients had undergone beroptic
bronchoscopy. Bronchoalveolar lavage (BAL) was
performed in ve patients. ree of the patients had a
normal cellular pattern on BAL, whereas two patients
had an elevated lymphocyte count (30% and 25%). No
growth was observed in bronchoalveolar lavage cultures.
e diagnosis of COP was made by OLB in 11 (64.7%)
patients, by TBB in 5 (29.4%), and by VATS biopsy in
1 (5.9%) Hepatitis markers were found to be negative.
Collagen markers were also negative in 15 patients.
Among the collagen vascular markers, antinuclear
antibody (ANA) positivity was determined in one patient,
and anticardiolipin antibody positivity was determined
in another. However, no pathology was detected upon
rheumatologic evaluation. None of the patients were
further diagnosed with collagen vascular disease over the
course of the follow-up period.
e mean follow-up period of the patients was 28.7 ±
25.0 months (median: 23 months; range: 3–85 months).
Eleven patients (64.7%) received oral corticosteroid (OCS)
therapy; the mean starting dose of methylprednisolone
was 23.2 ± 3 mg (median: 20 mg, range: 16–32 mg)
and the mean treatment period was 8.5 ± 4.7 months
(median: 8 months, range: 2–18 months). ere was a
complete improvement without any brotic changes in
eight patients who received OCS. Five patients did not
receive treatment; one of them, having refused treatment,
subsequently showed a spontaneous improvement in
symptoms and chest radiography was also normal at the
end of the 21st month. Four patients who did not receive
treatment had mass lesions at the start of treatment and a
total excision of the lesion was performed in all. Fibrotic
Figure. Chest radiography of a patient with COP. Bilateral consolidation and ground glass opacities are seen on thoracic computed
tomography.
Table 3. oracic computed tomography ndings of the cases.
Findings N (%)
Consolidation 8 (47.1)
Consolidation and ground glass opacities 3 (17.7)
Consolidation and nodules 2 (11.8)
Mass 3 (17.6)
Pleural eusion and nodule 1 (5.9)
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NİKSARLIOĞLU et al. / Turk J Med Sci
changes secondary to the procedure were observed in the
four patients who had undergone excision. No recurrence
was observed in these patients over the course of the
approximately 20-month follow-up period. One patient
couldn’t use OCS because her serum glucose level was
at the upper limit of normal values, so clarithromycin
and an inhaled corticosteroid/long-acting beta-mimetic
combination therapy were started. Partial regression was
seen on chest X-rays within 2 months but pulmonary
symptoms like cough and dyspnea persisted and a new
inltration was observed in a dierent location in the 3rd
month of follow-up. Aer excluding infectious etiologies,
32 mg of methylprednisolone was added to the existing
clarithromycin therapy. e patient is currently still being
followed. None of the patients in this study died over the
course of the follow-up period.
One patient was excluded for recurrence analyses
because the follow-up period was shorter than 5 months
(6). ree patients (18.7%) who received OCS developed a
recurrence of the disease during the course of the follow-
up period. Radiologic and clinic recurrence was detected
in two cases aer the steroid dose had been decreased;
therefore, the methylprednisolone dose was increased to 8
mg (stable dose for symptoms and radiological regression)
and regression was determined in the symptoms and
radiological ndings during follow-up. e patients were
in the 9th and 5th months of treatment when this article
was written and are still being followed. Partial regression
was observed in one patient receiving OCS.
4. Discussion
COP is a disease of unknown etiology and is diagnosed
histopathologically. (7). It was observed predominantly
in women and patients were aged between 29 and 69
years in our study. Common symptoms included cough
and dyspnea on exertion. Pleuritic chest pain and
weakness were seen in one-third of the patients. e main
radiological presentation of COP was consolidation in the
lower lobe. Corticosteroids are a good treatment option
in general, but relapse may occur. Clarithromycin therapy
did not prevent relapse in our patient.
COP is a subacute disease seen approximately between
the ages of 50 to 60 years, with an equal prevalence in
males and females (7–9). In the present study, the mean
age of our patients was 49.8 years and 10 of them were
female. e number of female patients was slightly higher
in the present study, and this was similar to the study of
Lazor et al. (10). COP is, in particular, more prevalent in
nonsmoking females and/or females who have stopped
smoking (10). In our patient group, 11 of the 17 patients
were nonsmokers, and two of the three female smokers had
stopped smoking. Despite the limited number of patients
in this study it can be seen that COP was more prevalent in
nonsmokers or in those who had stopped smoking.
e duration of symptoms varied between 1 and 3
months, with a mean duration of 1 month. Some studies
have reported a prolonged duration of symptoms,
up to 2–4 months (10–12). COP cases are frequently
diagnosed as pneumonia based on clinical, laboratory,
and radiological ndings. However, a denitive diagnosis
is made from further analyses performed in patients who
are unresponsive to treatment. e duration from onset
of symptoms to diagnosis varies between studies, and this
may lead to 6 to 10 weeks of delay in reaching a diagnosis
(8).
e most common symptoms encountered in our
patients were cough, dyspnea, pleuritic chest pain, and
weakness. Oymak et al. conducted a study of 26 cases
with bronchiolitis obliterans organizing pneumonia
(BOOP) and reported cough, dyspnea, pleuritic chest
pain, hemoptysis, and fever as being the most common
symptoms (3). Two patients were determined to have mild
hemoptysis in the present patient series. Hemoptysis has
been rarely determined in many previous studies, with
no information on the prevalence. A paper published in
2011 reported cough, fever, weakness, and dyspnea as the
most common symptoms in a group of 40 cases (12). In
that study, fever frequency was higher than in our study
(25% vs. 71.8%). Pleuritic chest pain is present particularly
in cases of peripheral lesions and pleural eusion. In the
present group, pleuritic chest pain was determined in six
cases. e prevalence of this symptom was close to the
rates found in some previous studies (3,13).
Considering the results of laboratory tests, previous
studies have reported slightly elevated ESR and serum
CRP levels and nonspecic increases in the peripheral
neutrophil count (5,14). In the present study, ESR was
found to be elevated in ve cases, CRP in four cases, and
peripheral eosinophil count in two cases in comparison
to the reference values. In another study, ANA positivity
was detected in 18.2% of patients and rheumatoid factor
positivity was detected in 10.3% (12). Yoo et al. compared
cases with COP with cases with connective tissue disease-
related organizing pneumonia and reported ANA positivity
in 31.9% of COP patients (15). In our patient group there
was isolated ANA positivity in one case and anticardiolipin
antibody positivity in another. No rheumatologic disease
was determined during follow-up in any of the cases.
ere are three main imaging patterns of COP: the
most prevalent is the alveolar opacities, followed by
solitary opacities and inltrative opacities. Migratory
bilateral patchy alveolar inltrates are the most typical
imaging patterns of COP (2,8,13). Alveolar opacities were
reported with a prevalence of 69% to 82% (10,12,16).
Drakopanagiotakis et al. determined consolidation in 82%
of their cases and observed migrating inltrates in 11.5%
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NİKSARLIOĞLU et al. / Turk J Med Sci
of them (12). ere are also publications that suggest that
a reversed halo sign is especially typical of COP (18,19).
Similar to the previous studies, consolidation was observed
in 76.6% (n = 13) of our cases. In addition, consolidations
with millimetric nodules (11.8%) or ground glass opacities
(17.7%) were observed in some cases. However, migrating
inltrates were observed in only four patients. e
reversed halo sign was not observed in any patient. Lee
et al. evaluated radiological ndings in COP patients and
found that consolidation was present in 17 (77%) out of 22
cases, in agreement with the results of our patient group.
Moreover, 86% of the patients had ground glass opacities
and 32% had nodules (19). e second most prevalent
radiological pattern in COP is solitary opacities or mass
lesions. e diagnosis of such cases is made by OLB since
these lesions may be radiologically confused with alveolar
adenocarcinoma (7). Drakopanagiotakis et al. observed
mass lesions in 8.2% of COP cases (12). Among our cases, a
diagnosis of COP was made by OLB in four (23.5%) patients
who had a mass image on thoracic CT. ree patients with
mass lesions were evaluated by PET-CT; the FDG uptake
(SUVmax) was 7.5 and 10, respectively, in two cases. FDG
uptake was not determined in one of these cases. In the
literature, a study of COP patients with PET-CT reported
that the mean SUVmax value was 2.47 (20). Tateishi et al.
reported that SUVmax is higher in consolidations with an
air bronchogram as compared to those without, and that it
is correlated with disease activity (21). Two patients with
FDG uptake on PET-CT showed a complete radiological
regression with no sign of malignancy over the course of
a 23-month and 22-month follow-up period, respectively.
In some publications, it has been stated that 10%–
20% of patients might have unilateral or bilateral pleural
eusion (22–24). In our group, minimal pleural eusion
was detected in only one patient with a mass lesion. In
all probability, there will be radiological diversity as the
number of patients increases.
e most common PFT nding in COP patients was
a mild to moderate restrictive ventilatory pattern and
decreased diusion capacity (7,8). An obstructive pattern
may be observed in smokers. In our study, a restrictive
pattern was determined in ve patients, and an obstructive
pattern was determined in one patient who was a smoker.
Normal PFT was determined in the remaining patients.
Only three patients had DLCO test ndings with decreased
diusion capacity, which was consistent with the literature.
In our patient group, 15 patients had undergone
bronchoscopy, and infectious etiologies were excluded
based on the examination of the lavage uid. In our group,
diagnosis was made by OLB in 11 (64.7%) cases, by TBB
in 5 (29.4%), and by VATS in only one case. Contrary
to the present study, Oymak et al. diagnosed by TBB in
46% of their cases (3). Lazor et al. diagnosed COP by
OLB/VATS in 69% of 48 cases and by TBB in 31% (10).
Although the number of patients was dierent than ours,
the rate of diagnostic methods used was similar to that
used in our study. Patients with mass lesions had been
diagnosed by OLB since the provisional diagnosis also
included malignancy. Moreover, patients that could not
been diagnosed by TBB also underwent OLB.
Standard treatment of COP includes corticosteroids.
Regression in symptoms and radiological improvement
are usually observed over the course of days (7). Lee et al.
stated that response to corticosteroids is better in lesions
with an air bronchograms (25). In previous studies, the
starting daily dose of corticosteroid therapy was 0.75–1.5
mg/kg. Treatment was continued at those doses for 2–4
weeks and then discontinued at 6–12 months by gradually
decreasing the dose (7,8,10). In our study, 12 patients
(70.6%) received OCS: eight patients showed a complete
resolution, but three (18.7%) developed recurrence as
the dose of corticosteroid was decreased. Radiological
regression in patients that received OCS is consistent with
the literature (7,10). In this study, one patient showed
regression while undergoing clarithromycin therapy. In
that case, OCS was added to the treatment regimen as the
patient showed progression during follow-up. Treatment
with dierent agents such as macrolides has become a
current issue in the presence of steroid-related adverse
eects or where steroids are contraindicated due to various
reasons. e antiinammatory activity of macrolides has
been known for a long time. eir usage in organizing
pneumonia is based on this activity (26–28). However,
publications on this topic have usually been in the form
of case reports.
Although COP is generally a disease with good
prognosis, recurrence might develop while decreasing
the dose or stopping treatment in patients receiving
corticosteroids. In the literature, recurrence rates vary
between 9% and 58% (10,29). In our study, the recurrence
rate was 18.7%. e dierence between the recurrence
rates found in studies might have resulted from the
dierence in the frequency and the duration of follow-
up. In addition, the recurrence rates of both COP and
secondary organizing pneumonia have been reported
together in some publications. Nevertheless, a delay in
diagnosis and treatment increases the rate of recurrence,
as was reported by Lazor et al. (10). Moreover, elevated
gamma-glutamyl transferase, alanine aminotransferase,
and alkaline phosphatase enzyme concentrations were
detected in cases with multiple recurrences (10). In the
present study, the concentrations of these enzymes were
normal in the three patients with recurrence. In a recent
study, recurrence rates were found to have increased in
the three event zones (upper, intermediate, lower) of the
lungs involved (30). In our study, such an involvement
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NİKSARLIOĞLU et al. / Turk J Med Sci
was not observed in the patients that showed recurrence.
In Nishino et al.’s study, patients with high brin in
pathologic specimens were associated with COP relapse
(6). We retrospectively evaluated pathologic specimens
and only one patient had brin in biopsy. No relapse was
determined in this patient.
e most important limitations of the present study are
its retrospective nature and the limited number of cases.
In conclusion, COP was more prevalent in middle-
aged female patients in our study group, while cough and
dyspnea on exertion were the most common symptoms
in these cases. Analogous with the previous studies,
consolidation is the predominating radiological pattern.
Diagnosis can be reached by performing OLB or TBB. e
recurrence rate of COP is relatively low.
References
1. Colby TV. Pathologic aspects of bronchiolitis obliterans
organizing pneumonia. Chest 1992; 102: 38S-43S.
2. Travis WD, Costabel U, Hansell DM, King TE Jr, Lynch
DA, Nicholson AG, Ryerson CJ, Ryu JH, Selman M, Wells
AU et al. An ocial American oracic Society/European
Respiratory Society statement: Update of the international
multidisciplinary classication of the idiopathic interstitial
pneumonias. Am J Respir Crit Care Med 2013; 188: 733-748.
3. Oymak FS, Demirbas HM, Mavili E, Akgun H, Gulmez I,
Demir R, Ozesmi M. Bronchiolitis obliterans organizing
pneumonia. Respiration 2005; 72: 254-262.
4. Kıter G, Yuncu G, Bir F, Karabulut N, Özkurt S, Evyapan F.
Cryptogenic organizing pneumonia: two cases and an update.
Toraks Dergisi 2008; 9: 43-48 (in Turkish with English
abstract).
5. Kivanc T, Ekici ZU, Dogan CR, Kiyici H, Eyuboglu FO.
Cryptogenic organising pneumonia: four cases with dierent
radiological manifestations. Eurasian J Pulmonol 2011; 13:
114-120.
6. Nishino M, Mathai SK, Schoenfeld D, Digumarthy SR, Kradin
RL. Clinicopathologic features associated with relapse in
cryptogenic organizing pneumonia. Hum Pathol 2014; 45: 342-
351.
7. Cottin V, Cordier JF. Cryptogenic organizing pneumonia.
Semin Respir Crit Care Med 2012; 33: 462-475.
8. Cordier JF, Costabel U, du Bois R. Cryptogenic organizing
pneumonia. Orphanet Encyclopedia, October 2004. Available
online at http://www.orpha.net/consor/cgi-bin/OC_Exp.
php?Expert=1302.
9. Wells AU. Cryptogenic organizing pneumonia. Semin in
Respir Crit Care Med 2001; 22: 449-459.
10. Cordier JF. Cryptogenic organizing pneumonia. Eur Respir J
2006; 28: 422-446.
11. Lazor R, Vandevenne A, Pelletier A, Leclerc P, Court-Fortune I,
Codier JF. Cryptogenic organizing pneumonia: characteristics
of relapses in a series of 48 patients. Am J Respir Crit Care Med
2000; 162: 571-577.
12. King TE Jr, Mortenson RL. Cryptogenic and organizing
pneumonitis. e North American experience. Chest 1992;
102: 8S-13S.
13. Drakopanagiotakis F, Paschalaki K, Abu-Hijleh M, Aswad B,
Karagianidis N, Kastanakis E, Braman SS, Polychronopoulos
V. Cryptogenic and organizing pneumonia. Chest 2011; 139:
893-900.
14. Codier JF, Loire R, Brune J. Idiopathic BOOP: denition of
characteristic clinical proles in a series of 16 patients. Chest
1989; 96: 999-1004.
15. Cordier JF. Cryptogenic organizing pneumonitis. Bronchiolitis
obliterans organizing pneumonia. Clin Chest Med 1993; 14:
677-692.
16. Yoo JW, Song JW, Jang SJ, Lee CK, Kim MY, Lee HK, Jegal
Y, Kim DS. Comparison between cryptogenic organizing
pneumonia and connective tissue disease-related organizing
pneumonia. Rheumatology 2011; 50: 932-938.
17. Sara AG, Hamdan AJ, Hanaa B, Nawaz KA. Bronchiolitis
obliterans organizing pneumonia: pathogenesis, clinical
features, imaging and therapy review. Ann orac Med 2008;
3: 67-75.
18. Kim SJ, Lee KS, Ryu YH, Yoon YC, Choe KO, Kim TS, Sung
KJ. Reversed halo sign on high-resolution CT of cryptogenic
organizing pneumonia: diagnostic implication. AJR Am J
Roentgenol 2003; 180: 1251-1254.
19. Maimon N. A 47-year-old female with shortness of breath and
reversed halo sign. Eur Respir Rev 2010; 19: 1251-1254.
20. Lee JW, Lee KS, Lee HY, Chung MP, Yi CA, Kim TS, Chung MJ.
Cryptogenic organizing pneumonia: serial high resolution CT
ndings in 22 patients. AJR Am J Roentgenol 2010; 195: 916-
922.
21. Umeda Y, Demura Y, Ishizaki T, Ameshima S, Miyamori I,
Saito Y, Tsuchida T, Fujibayashi Y, Okazawa H. Dual-time point
18F-FDG PET imaging diagnosis of disease type and disease
activity in patients with idiopathic interstitial pneumonia. Eur
J Nucl Med Mol Imaging 2009; 36: 1121-1130.
22. Tateishi U, Hasegawa T, Seki K, Terauchi T, Moriyama N,
Arai Y. Disease activity and 18F-FDG uptake in organising
pneumonia: semi-quantitative evaluation using computed
tomography and position emission tomography. Eur J Nucl
Med Mol Imaging 2006; 33: 906-912.
23. Kim SJ, Lee KS, Ryu YH, Yoon YC, Choe KO, Kim TS, Sung
KJ. Reversed halo sign on high-resolution CT of cryptogenic
organizing pneumonia: diagnostic implications. AJR Am J
Roentgenol 2003; 180: 1251-1254.
1718
NİKSARLIOĞLU et al. / Turk J Med Sci
24. Lee KS, Kullnig P, Hartman TE, Muller NL. Cryptogenic
organizing pneumonia: CT ndings in 43 patients. AJR Am J
Roentgenol 1994; 162: 543-546.
25. Muller NL, Staples CA, Miller RR. Bronchiolitis obliterans
organizing pneumonia: CT features in 14 patients. AJR Am J
Roentgenol 1990; 154: 983-987.
26. Lee JS, Lynch DA, Sharma S, Brown KK, Muller NL. Organizing
pneumonia: prognostic implication of high-resolution
computed tomography features. J Comput Assist Tomogr 2003;
27: 260-265.
27. Stover DE, Mangino D. Macrolides: A treatment alternative for
bronchiolitis obliterans organizing pneumonia. Chest 2005;
128: 3611-3617.
28. Patnak V, Kuhn JM, Durham C, Funkhouser WK, Henke DC.
Macrolide use leads to clinical and radiological improvement
in patients with cryptogenic organizing pneumonia. Ann Am
orac Soc 2014; 11: 87-91.
29. Radzikowska E, Wiatr E, Gawryluk D, Langfort R, Bestry
I, Chabowski M, Roszkowski K. Organizing pneumonia –
clarithromycin treatment. Pol Pneumonol Allergol 2008; 76:
334-339.
30. Izumi T, Kitaichi M, Nishimura K, Nagai S. Bronchiolitis
obliterans organizing pneumonia: clinical features and
dierential diagnosis. Chest 1992; 102: 715-719.
