大韓ñHH흉醫學會註‘ 第 24 卷 第 2 號 pp. 278 - 281 , 1988 Journal of Korean Radiological Society, 24(2) 278-281 , 1988

CT Characteristics of Peripheral Organizing Pneumonia

Seoung Oh Yang, M.D. , Chul Soon Choi, M.D.치 Myung Joon Kim , M.D., Kyung SOO Lee, M.D.,

Hyung Sik Choi, M.D. , Young Hwan Jun, M.D. and Yong Koo Park, M.D.**

Department of Radiology, Capital Armed Forces Ceneral Hospital

〈국문초록〉 기질화 폐엽의 전산화단층촬영소견

-증례 보고-

국군수도병원 방사선과

앙승오 • 최칠순 김명준 • 이경수 • 최형식 • 전영환 • 박용구 ••

기질화 폐 엽이 원위 폐야에서 고링성으로 오래 지속되는 경우에 단순 흉부사진만으로는 악성 종양파

의 강벨이 어렵다. 최근에 고해상력의 천산화 단층촬영으로 폐실질의 명변의 진단에 많은 도웅을 얻고

있으나， 원위부의 기 질화 페 염 의 전산화 단충촬영 소견은 흔하지 않은 펀이 마. 저 자들은 수술을 하여 영

리학적」뜨로 확인펀 기질화 폐염 1예의 전산화 단층펠영소견을 보고하는 바이 다.

Diagnostic dilemma of persistent mass-forming parenchymal opacity in the lung periphe ry occurs occa­

sionally in the realm of diagnostic radiology. Until recently, li terature on the ro le of computed tomography

in peripheral o rganizing pneumonia, which is difficult to differentiate from mali gnancy, has little been publish­

ed. We expe ri enced one case of pathologica ll y proven o rganizing pneumonia diagnosed preoperatively by

chest ct When it comes to solitary peripheral mass density in the lung, we think that CT can be proved usef비

in the diagnosis of benign organizing pneumonia by showing regular and smoothly corrugate margin, peripheral

contrast enhancement with inner low density, and air-trapping by intervening normal lung parenchyma

Introduction

The application of computed tomography(CT)

in the evaluation of focal lung disorders has not

actively evolved at the same pace as other pul-

• 공군 항공의학연구원 * Department of Radiologι Aeromedical Research Center

• 국군수도영원 영리과 * * Department of Pathologκ Capital Armed Forces Ceneral

Hospital

이 논운은 1988년 2월 27일에 접 수하여 1988년 3월 19 일에 채택되었음.

monary diseases including mediastinum1,2). The

value and findings of chest CT in assessing mass­

forming peripheral organizing pneumonia which is

often difficult to differentiate from a lveolar cell

carcinoma , solitary pulmonary infarct and so on

h ave not been f비ly clarified ye t. We h ave

observed some helpful CT findings of surgically

proven organizing pneumonia located in the lung

periphery , so we wish to present radiologic fin­

dings with emphasis on the differential diagnosis

of solitary peripheral mass-fo rming density in the

lung.

- 278 -

- Seoung Oh Yang , et al.: CT Characterist ics 01 Peripheral Organizing Pneumonia

Case Report

A 33-year-이d man was referred to our hospital

because of flu-like symptoms for two weeks despite

empiric antibiotics coverage. There was a decre­

aseè. breathing sound on right lower lung field

with inspiratory rale at admission . Laboratory data

was not specific. Plain chest radiographs showed

elliptical opacity along right retrocardiac space

abutting thoracic spine with rather fluffy mar­

gin(Fig. l-A , B). Owing to persistent mass-for­

ming lesion , we performed chest CT which re­

vealed craggy-surfaced ovoid soft tissue density

with contrast enhancement peripherally and inter­

nal low density , and a few cr air-bronchograms

by intervening normal lung tissues(Fig. l-C , D).

On the 30th day following admission , right lower

lobectomy was performed to eliminate the mass

lesion which was shown 6 cm-sized relatively firm

soft tissue mass in the posteromedial segment of

right lower lobe adhered to the parietal pleura.

Pathologic cut surface showed yellowish tan necro­

tic focus in the lung specimen and its final diag­

nosis was orgamzmg penumonia with fibrosis(Fig .

l-E).

Discussion

To date , the role of CT in the evaluation of

patients with air-space disease has gone minimally

explored. This is primarily because of the ease

with which air-space disease is diagnosed from

plain chest radiographs 1) . According to Gener­

eux2) , CT has little role to play during the acute

phase of the pneumonias apart from its valuable

assistance in identifying some of the compli­

cations(cavity formation , bronchopleural fistula , empyema). Ovetall consideration of in f1ammatory

disorders is beyond the scope of this report , we

would like to focus our interest on the CT features

of peripheral mass-forming organizing pneumonia

which used to be found by us after its acute stage.

The term of organizing penumonia seems to be

less distinct from the standpoint of its underlying

pathologic morphology. Recently there has been

several articles reinvestigate bronchiolitis obliter­

ans organizing pneumonia(BOOP) because it has a

favorable prognosis and good response to steriod

therapy3-S) McLoud et a l. said that localized le­

sion with bronchilolitis obliterans is usually refer­

red to as “ focal organizing pneumonia" and its

detailed description of CT feature is rare , but the

appearance is that of an irregular sublobar area of

air-space consolidation4) We think our case is not

quite dissimilar to that of localized BOOP ,

although the pathologic pattern of bronchial ob­

struct lOn IS not promment

Differential diagnoses include unifocal alveolar

cell carcinoma , single pulmonary infarct , rounded

atelectasis and subpleural tuberculoma. Relatively

uncommon unifocal alveloar cell carcinoma is in­

distinguishable on the basis of CT features ,

although frequent association with hilar or media­

stinal lymphadenopathy will favor the malig­

nancy6) We think smooth undulated surface and

surrounding contrast enhancement pattern and air­

-<lensities by normal parenchyma are helpful

aspects of organizing pneumonic process on chest

cr. P비monary thromboembolism with pleural

based area of consolidation may mimic infla­

mmation but often m비tiple. Pulmonary embolus

can be determined by radionuclide perfusion scan

when there is only one area of parenchymal den­

sity on the plain radiograph2) . Rounded atelectasis

as a benign from of peripheral lung collapse may

be differentiated by the characteristic pleural de­

formity with acute angle , curvilinear entrapment

of vessels and bronchi and some other CT signs7) .

Subpleural tuberculoma tends to be sharply cir­

cumscribed and there may be small satellite lesions

in the vicinity of a somewhat large granuloma with

frequent parenchymal infiltration and calcifica­

tion2) .

279 -

A

C

E

-大韓放射線훌훌學會誌 : 第 24 卷 第 2 號 1988-

280 -

A, B. Plain chest radiographs show elongated mass shadow at posteromedial segment of

right lower lobe C ,D. CT scan demonstrates scalloped-margi ­

nated soft tissue density with inner low density after contrast enhan­cement(INSET with arrows). See multiple air-containing spaces surrounding the den­sity(Open arrows)

E. P hotomicrograph of the resected lung re veals patchy air-space fi bros is(arrows) with interstitial infiltration of the chronic inflammatory cells . Alveolar walls are hypercellular and thi ckened(H-E , x 100)

B

[

-Seoung Oh Yang , et al.: CT Characteristics of Peripheral Organizing Pneumonia-

In summary , CT features of rather smoothly

corrugate margin , peripheral contrast enhan­

cement with inner low density , surrounding air­

densities and absent lymphadenopathy in the case

of peripheral mass-forming opacity favor the diag­

nosis of organizing pneumonia although not speci­

fic . Appropriate cIinical setting and temporal

change are also helpful in the diagnosis .

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5. Müller NL , Guerry'Force ML , Stap les CA et al

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