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983
CT Findings in Benign Fibrous Mesothelioma of the Pleura: Pathologic Correlation in Nine Patients
Kyung
Soo Lee1 Jung-Gi 1rn2 Kyu Ok Choe3 Chang Jin Kim4
B”oun’’
Ho Lee1
I
The CT findings described previously,
in cases
with the pathologic
appearance
in nine proved pathologic
of
benign
but little attention
cases
findings
the
areas
to a correlation of these findings Accordingly, we analyzed the CT scans
pathologic
CT
(available in eight patients), the Pathologic examination showed culanty of the tumor. Areas of hemorrhage (n = 3) seen in the
low-attenuation
rnesotheliorna
has
been
of the tumors.
in which with
fibrous
studies
appearance
of the
pleura
have
been
given
of
were the
available
tumors.
On
and compared enhanced
CT
the scans
lesions showed significant enhancement in all cases. that the enhancement could be explained by the vasmyxoid (n = 7) or cystic (n = 3) degeneration and pathologic specimens correlated with round or tubular
on unenhanced
and enhanced
CT scans.
On unenhanced
CT
scans (n = 3), the tumor density was the same as that of the surrounding musculature. Calcification was seen in one patient. Large lesions showed lobulated borders, but no invasion into the lung parenchyma and chest wall was noted. There was no pleural effusion. Our experience vascularity
the
foci of myxoid
suggests that intense enhancement of the tumors. Areas of low attenuation
of the tumors in the tumors
or cystic
in the lesion.
158:983-986,
AJR
degeneration
and hemorrhage
occurs because on CT were due
of to
May 1992
Benign fibrous mesotheliomas of the pleura, also called solid fibrous tumors of the pleura, are rare tumors of mesodermal origin. They amount to less than S% of all neoplasms involving the pleura [1 2]. The tumors are usually discovered as asymptomatic lesions on routine chest radiographs. Benign fibrous mesotheliomas have a good prognosis compared with the diffuse malignant variety. Benign ,
mesotheliomas
occur
in patients
of all ages. There is no sex predilection
and no
evidence of a rebationship to asbestos exposure. Two reports describing the CT appearances of benign fibrous mesothebiomas have been published [2, 3]. To our best knowledge, however, little emphasis has been given to the CT-pathologic correlation of the tumors. The purpose of this Received August 22, i991 ; accepted sion November 9, 1991 . 1
Department
after revi-
study was to review the CT features the findings on pathobogic examination
in nine proved cases of the tumors.
and compare
them
with
of Radiology, College of Medicine,
Soonchunhyang
University, 23-20, Bongmyung330-100, Korea. Address reprint to K. S. Lee.
Dong, Chunan, requests 2
Department
of Radiology, College
of Medicine,
Seoul National University, Seoul, 110-460, Korea. 3
Department
Yonsei 4
University,
Department
Soonchunhyang Korea. 036i -803X/92/1 0 American
of Radiology, College of Medicine, Seoul,
i20-140,
of Pathology, University,
Korea.
College of Medicine, Chunan, 330-iOO,
585-0983
Roentgen
Ray Society
Materials
and
Eleven
cases
treated
from
patients
in whom
was
proved
Methods of benign
January on
fibrous
1 985
pathologic the
basis
confirmation of pathologic
select the cases were spindle-shaped fibrocytes
minimal and/or
old (average,
Mild chest
four patients large
lesion.
48 years).
had no specific The
size
mesothelioma
to January
of the
1 991
of the pleura were
collected
was available
were selected
examination
in all nine
nuclear pleomorphism fibroblasts. The five
tumors
Hypoglycemia ranged
cases.
four
patients
institutions.
for study. Histologic
from
in five patients;
criteria
in longest
to
of the years
the remaining
was seen in one patient 3 to 20 cm
Nine
The diagnosis
and rare or absent mitoses men and four women were 23-71
pain was the main complaint
complaints. excised
in i 1 consecutive from
who diameter
had a and
984
LEE
ET AL.
AJR:i58,
Downloaded from www.ajronline.org by Vrije Universiteit Brussel on 10/16/15 from IP address 134.184.26.108. Copyright ARRS. For personal use only; all rights reserved
4::
\
Fig. 1.-Benign
fibrous
mesothelioma
in a 53-
is obtuse.
1
from 30 to 1 468 9 in weight. The tumor was in the left hemithorax in six patients and in the right hemithorax in three. Except for one patient who had a mass originating from the diaphragmatic pleura, all patients had tumors arising from the visceral pleura surgically and pathologically. lntrafissural tumor was seen in two patients. A short tumor pedicle was noted in three patients during surgery, but no tumors were seen to change location when conventional chest radiographs, including those obtained with the patient in the decubitus were
reviewed.
No evidence
of rib destruction
or chest
wall
invasion was seen at surgery in any of the patients. In five patients with large tumors, adhesion between the lesion and the pleura or the
was noted,
pericardium
but surgical
resection
was still possible.
Follow-up chest radiographs after surgical excision of the tumor were available in all patients. During the follow-up period of 4 months to 6
years (average, 24 months), no tumors recurred. Most CT scans were obtained with a GE 9800 scanner (General Electric, Milwaukee, WI) or a CT-W 700 scanner (Hitachi Medical Corp., Tokyo). Scanning parameters were 120 kVp, iOO mA, and 3sec scan time for the GE 9800 scanner and 120 kVp, 400 mA, and 3-sec
scan
time
were available
for the CT-W
700 scanner.
Enhanced
scans
only
and both unenhanced and enhanced scans were available in two patients. Unenhanced scans only were done in one patient. In most patients, enhanced scans were obtained with injection of 1 00 ml of 68.3% meglumine ioglicate (Rayvist A 300, Schering,
Seoul,
drip infusion with 10-mm photographed
in six patients
Korea),
50 ml in bolus
before
-.:
Fig. 2.-Benign fibrous mesothelioma in a 64-year-old man. A, Enhanced CT scan shows large and highly enhancing mass lesion occupying right anterior and middle hemithorax. Attenuation value of lesion is same as that of heart. Multiple tubular lowattenuation areas (arrows), denoting areas of myxoid degeneration, are also seen. Small mixedattenuation lesion (arrowheads) posterior to main lesion is incidental hamartoma in posterioriy displaced right middle lobe. B, Cut surface of gross specimen reveals a yellowish white mass lesion with scattered prominent vessels (white arrows). Portions of myxoid degeneration (black arrows) are also found. Incidental hamartoma (arrowheads) in right middle lobe is located and photographed in anterior aspect of main lesion.
year-old woman. Enhanced CT scan shows homogeneous and highly enhancing mass in left anterior pleural space. Angle between mass and chest wall
position,
May 1992
scanning
and
50 ml in
during scanning. At full inspiration, contiguous scans collimation were obtained at 1 0-mm intervals. Scans in narrow window (window width, 400; window level, 25) were used in CT analysis. CT characteristics analyzed retrospectively included the attenuation values and internal architecture of the mass; the angle between the mass and the surrounding pleura or the chest wall; the contour and margin of the mass; the presence of calcification; and associated findings in the pleura, lung parenchyma, and chest wall. The attenuation value of the tumors was compared with that of the surrounding
musculature.
The
correlated specific
with
attenuation
the
gross
values pathologic
areas of the specimens
of the features
were
mass
on CT
of the
then studied
scans
tumors.
were These
microscopically.
Results
CT Findings The
tumors
enhanced
showed
predominantly
scans in all patients
high
attenuation
(Figs. 1-5). The average
on
atten-
uation value of the enhancing tumors, measured in four patients, was 121 H, whereas that of the surrounding musculature was 65 H. On unenhanced scans in three patients, the tumors appeared to have intermediate attenuation (mean, 38 H). The CT appearance of the tumor depended on its size.
Small tumors
in two patients
(
983
CT Findings in Benign Fibrous Mesothelioma of the Pleura: Pathologic Correlation in Nine Patients
Kyung
Soo Lee1 Jung-Gi 1rn2 Kyu Ok Choe3 Chang Jin Kim4
B”oun’’
Ho Lee1
I
The CT findings described previously,
in cases
with the pathologic
appearance
in nine proved pathologic
of
benign
but little attention
cases
findings
the
areas
to a correlation of these findings Accordingly, we analyzed the CT scans
pathologic
CT
(available in eight patients), the Pathologic examination showed culanty of the tumor. Areas of hemorrhage (n = 3) seen in the
low-attenuation
rnesotheliorna
has
been
of the tumors.
in which with
fibrous
studies
appearance
of the
pleura
have
been
given
of
were the
available
tumors.
On
and compared enhanced
CT
the scans
lesions showed significant enhancement in all cases. that the enhancement could be explained by the vasmyxoid (n = 7) or cystic (n = 3) degeneration and pathologic specimens correlated with round or tubular
on unenhanced
and enhanced
CT scans.
On unenhanced
CT
scans (n = 3), the tumor density was the same as that of the surrounding musculature. Calcification was seen in one patient. Large lesions showed lobulated borders, but no invasion into the lung parenchyma and chest wall was noted. There was no pleural effusion. Our experience vascularity
the
foci of myxoid
suggests that intense enhancement of the tumors. Areas of low attenuation
of the tumors in the tumors
or cystic
in the lesion.
158:983-986,
AJR
degeneration
and hemorrhage
occurs because on CT were due
of to
May 1992
Benign fibrous mesotheliomas of the pleura, also called solid fibrous tumors of the pleura, are rare tumors of mesodermal origin. They amount to less than S% of all neoplasms involving the pleura [1 2]. The tumors are usually discovered as asymptomatic lesions on routine chest radiographs. Benign fibrous mesotheliomas have a good prognosis compared with the diffuse malignant variety. Benign ,
mesotheliomas
occur
in patients
of all ages. There is no sex predilection
and no
evidence of a rebationship to asbestos exposure. Two reports describing the CT appearances of benign fibrous mesothebiomas have been published [2, 3]. To our best knowledge, however, little emphasis has been given to the CT-pathologic correlation of the tumors. The purpose of this Received August 22, i991 ; accepted sion November 9, 1991 . 1
Department
after revi-
study was to review the CT features the findings on pathobogic examination
in nine proved cases of the tumors.
and compare
them
with
of Radiology, College of Medicine,
Soonchunhyang
University, 23-20, Bongmyung330-100, Korea. Address reprint to K. S. Lee.
Dong, Chunan, requests 2
Department
of Radiology, College
of Medicine,
Seoul National University, Seoul, 110-460, Korea. 3
Department
Yonsei 4
University,
Department
Soonchunhyang Korea. 036i -803X/92/1 0 American
of Radiology, College of Medicine, Seoul,
i20-140,
of Pathology, University,
Korea.
College of Medicine, Chunan, 330-iOO,
585-0983
Roentgen
Ray Society
Materials
and
Eleven
cases
treated
from
patients
in whom
was
proved
Methods of benign
January on
fibrous
1 985
pathologic the
basis
confirmation of pathologic
select the cases were spindle-shaped fibrocytes
minimal and/or
old (average,
Mild chest
four patients large
lesion.
48 years).
had no specific The
size
mesothelioma
to January
of the
1 991
of the pleura were
collected
was available
were selected
examination
in all nine
nuclear pleomorphism fibroblasts. The five
tumors
Hypoglycemia ranged
cases.
four
patients
institutions.
for study. Histologic
from
in five patients;
criteria
in longest
to
of the years
the remaining
was seen in one patient 3 to 20 cm
Nine
The diagnosis
and rare or absent mitoses men and four women were 23-71
pain was the main complaint
complaints. excised
in i 1 consecutive from
who diameter
had a and
984
LEE
ET AL.
AJR:i58,
Downloaded from www.ajronline.org by Vrije Universiteit Brussel on 10/16/15 from IP address 134.184.26.108. Copyright ARRS. For personal use only; all rights reserved
4::
\
Fig. 1.-Benign
fibrous
mesothelioma
in a 53-
is obtuse.
1
from 30 to 1 468 9 in weight. The tumor was in the left hemithorax in six patients and in the right hemithorax in three. Except for one patient who had a mass originating from the diaphragmatic pleura, all patients had tumors arising from the visceral pleura surgically and pathologically. lntrafissural tumor was seen in two patients. A short tumor pedicle was noted in three patients during surgery, but no tumors were seen to change location when conventional chest radiographs, including those obtained with the patient in the decubitus were
reviewed.
No evidence
of rib destruction
or chest
wall
invasion was seen at surgery in any of the patients. In five patients with large tumors, adhesion between the lesion and the pleura or the
was noted,
pericardium
but surgical
resection
was still possible.
Follow-up chest radiographs after surgical excision of the tumor were available in all patients. During the follow-up period of 4 months to 6
years (average, 24 months), no tumors recurred. Most CT scans were obtained with a GE 9800 scanner (General Electric, Milwaukee, WI) or a CT-W 700 scanner (Hitachi Medical Corp., Tokyo). Scanning parameters were 120 kVp, iOO mA, and 3sec scan time for the GE 9800 scanner and 120 kVp, 400 mA, and 3-sec
scan
time
were available
for the CT-W
700 scanner.
Enhanced
scans
only
and both unenhanced and enhanced scans were available in two patients. Unenhanced scans only were done in one patient. In most patients, enhanced scans were obtained with injection of 1 00 ml of 68.3% meglumine ioglicate (Rayvist A 300, Schering,
Seoul,
drip infusion with 10-mm photographed
in six patients
Korea),
50 ml in bolus
before
-.:
Fig. 2.-Benign fibrous mesothelioma in a 64-year-old man. A, Enhanced CT scan shows large and highly enhancing mass lesion occupying right anterior and middle hemithorax. Attenuation value of lesion is same as that of heart. Multiple tubular lowattenuation areas (arrows), denoting areas of myxoid degeneration, are also seen. Small mixedattenuation lesion (arrowheads) posterior to main lesion is incidental hamartoma in posterioriy displaced right middle lobe. B, Cut surface of gross specimen reveals a yellowish white mass lesion with scattered prominent vessels (white arrows). Portions of myxoid degeneration (black arrows) are also found. Incidental hamartoma (arrowheads) in right middle lobe is located and photographed in anterior aspect of main lesion.
year-old woman. Enhanced CT scan shows homogeneous and highly enhancing mass in left anterior pleural space. Angle between mass and chest wall
position,
May 1992
scanning
and
50 ml in
during scanning. At full inspiration, contiguous scans collimation were obtained at 1 0-mm intervals. Scans in narrow window (window width, 400; window level, 25) were used in CT analysis. CT characteristics analyzed retrospectively included the attenuation values and internal architecture of the mass; the angle between the mass and the surrounding pleura or the chest wall; the contour and margin of the mass; the presence of calcification; and associated findings in the pleura, lung parenchyma, and chest wall. The attenuation value of the tumors was compared with that of the surrounding
musculature.
The
correlated specific
with
attenuation
the
gross
values pathologic
areas of the specimens
of the features
were
mass
on CT
of the
then studied
scans
tumors.
were These
microscopically.
Results
CT Findings The
tumors
enhanced
showed
predominantly
scans in all patients
high
attenuation
(Figs. 1-5). The average
on
atten-
uation value of the enhancing tumors, measured in four patients, was 121 H, whereas that of the surrounding musculature was 65 H. On unenhanced scans in three patients, the tumors appeared to have intermediate attenuation (mean, 38 H). The CT appearance of the tumor depended on its size.
Small tumors
in two patients
(
