Surgical Science, 2011, 2, 360-362
doi:10.4236/ss.2011.26078 Published Online August 2011 (
Copyright © 2011 SciRes. SS
A Pulmonary Infarction Mimicking Metastatic
Lung Tumor
Koji Teramoto, You Kawaguchi, Tetsuo Hori, Yasuhiko Ohshio, Masayuki Hashimoto,
Shoji Kitamura, Jun Hanaoka, Noriaki Tezuka
Department of Surgery, Shi ga Universi t y of Medic al Sci ence, Otsu, Japan
Received May 9, 2011; revised July 1, 2011; accepted July 22, 2011
Pulmonary infarction may present as a solitary pulmonary nodule resembling a malignant pulmonary tumor.
A 71-year-old woman who had undergone the surgery for abdominal malignant fibrous histiocytoma (MFH)
with inflammatory nature presented with a small nodule in the right lung in computed tomographic images.
Two months later, the nodule became enlarged and had an accompanying infiltrative shadow. We suspected
a metastatic tumor from MFH and performed video-assisted thoracic surgery. However, subsequent patho-
logical diagnosis of the nodule was pulmonary infarction due to thromboembolism. When a peripheral nod-
ule is detected, pulmonary infarction should be considered as a possible diagnosis.
Keywords: Pulmonary Infarction, Lung Cancer, VATS
1. Introduction
Pulmonary infarction may present as a solitary pulmo-
nary nodule, presenting radiologically as peripheral
wedge-shaped parenchymal opacities [1-3]. However, in
some cases, it may present as a nodule resembling a pri-
mary or metastatic lung tumor [4]. In previous reports on
a pulmonary infarction, there are few reports describing
its radiological findings altered with time. Here, we re-
port a case of pulmonary nodule mimicking a metastatic
tumor that was subsequently diagnosed as pulmonary
infarction following video-assisted thoracic surgery
(VATS). The altered radiological findings of the pulmo-
nary nodule in our case made us suggest a metastatic
2. Case Report
A 71-year-old woman who had undergone surgery for
abdominal malignant fibrous histiocytoma (MFH) pre-
sented with a pulmonary nodule in the right lower lobe,
S8, on chest computed tomography (CT) during follow-
ing-up. The nodule was 8 × 7 mm in size with regular
margin (Figure 1(a)). Two months later, the nodule had
enlarged to 20 × 10 mm in size and was accompanied by
a surrounding infiltrative shadow (Figure 1(b)). Consid-
ering her past history of MFH, which had a potent in-
(a) (b)
Figure 1. (a) Chest CT showing a small nodule in right lung,
S8; (b) two months later, it had enlarged to be accompanied
by a surrounding infiltrative shadow .
flammatory background, the nodule was suspected to be
a metastatic tumor from MFH. She was subsequently
referred to our department for diagnosis confirmation
and removal of the nodule. Suspecting the nodule to be a
metastatic tumor as well, we conducted VATS to excise
it. During surgery, the visceral epipleura of the nodule
was found to be thickened and grey in co lor. There were
no findings related to the local inflammation of the nod-
ule, that is, accumulation of reactive pleural effusion,
adhesion of the nodule to the chest wall, and angiogene-
sis around the nodule. W e could resect the nodule easily.
Upon removal, the nod ule was found to be of elastic ha rd
consistency and 20 × 20 × 15 mm in size. The cut sur-
face of the nodule was dark red in color (Figure 2(a))
and it was pathologically diagnosed as a pulmonary in-
farction caused by thromboembolism (Figure 2(b)). Ma-
lignant cells were not detected in the resected specimen.
3. Discussion
Pulmonary infarctions typically result from pulmonary
thromboembolism. Other than this, non-thromboembolic
causes of pulmonary infarctions include pulmonary in-
fections, diffuse alveolar damage, pulmonary torsion,
lung cancer, amyloidosis, bronchial artery embolization
therapy, and intravenous catheter embolization [5]. In
this case, pulmonary infarctions resulted from pulmonary
thromboembolism but causes of thrombus were not fully
revealed. The patient had lower risk to occur the throm-
bus, that is, she had neither varix of the lower limb nor
atrial fibrillation. And sh e took an or al anti-co ag lant drug
Figure 2. (a) The resected specimen of the pulmonary nod-
ule; (b) HE-staining of the nodule demonstrating necrotic
tissue at the subpleural region.
which was for prevention from cerebral infarction. A
speculation about the cause of thrombus is that past sur-
gery for MFH might set off occurrence of deep vein
Radiologically, pulmonary infarction appears as
hump-shaped opacities located in the subpleural space
[1-3]. Pulmonary infarctions are generally polyhedral,
conform to a secondary pulmonary lobule, and have a
bronchovascular connection directed toward the hilum
[1]. However, they may assume various other shapes,
partly due to associated hemorrhage and edema. In this
case, a solitary small nodule was initially detected on
chest CT. Two months later, the nodule had become
enlarged and had an accompanying infiltrative shadow.
Taking into consideration that the patient’s MFH had
inflammatory in nature, we suspected that the nodule
might to be a metastatic tumor fro m MFH. As a result of
the confusing change in findings on chest CT over a pe-
riod of two months, we did not conceive of pulmonary
infarction as a differential diagnosis. We assumed that
the small nodule initially detected had induced inflam-
mation or congestion in the area resulting in the infiltra-
tive shadow detected.
In a review of the previous cases, George and col-
leagues reported 43 instances of pulmonary infarction [4],
and six of which had features suggestive of lung cancer.
Three of six cases were enhanced positively on con-
trast-enhanced CT, two cases were hyper-metabolic on
positron emission tomography (PET). More information
may be given by not contrast-enhanced but multi-sliced
CT for preoperative diagnosis of pulmonary infarction.
PET seems to contribute little to diagnosis because of
accompanied inflammation of pulmonary infarction. Ta-
kahashi and colleagues reported that pulmonary infarc-
tion should be considered as a differential diagnosis
when peripheral pulmonary nodules or masses are lo-
cated in the same lobes as the primary cancer [6]. There-
fore, we maintain that biopsy by minimally invasive
VATS is the most reliable method to diagnose pulmo-
nary infarction.
4. Conclusions
Based on this report, we suggest that in the case of pul-
monary nodules located peripherally in subpleural re-
gions, pulmonary infarction should be considered as a
differential diagnosis in patients with a past history of
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