Downloaded from www.ajronline.org by 120.36.151.163 on 11/05/15 from IP address 120.36.151.163. Copyright ARRS. For personal use only; all rights reserved
1009
Case
MR Imaging Toshifurni Yoshikazu
of Hepatic
Adenoma
Gabata,1 Osamu Matsui,1 Masurni Kornatsu,3 and Makoto Sasaki4
Kadoya,1
Tsutornu
[3, 4]. The MR appearance and MR has been unable
variable, diagnosis adenoma
of hepatic to provide
Takashima,1
On gradient-recalled
Hepatic adenoma is a rare benign tumor composed of benign hepatocytes in sheets and cords without an acinar architecture [1 ]. It is difficult to distinguish from well-differentiated hepatocellular carcinoma (HCC), both pathologically and radiologically [2]. MR imaging has become an important diagnostic technique for detecting and differentiating hepatic
tumors
1 0#{176} flip
angle),
acquisition
tumor,
in reported cases [3-5]. We report a case of hepatic with a characteristic appearance on MR images.
encapsulated
capsule (Fig.
Results
of physical
examination
were
normal.
pain and 10 years
central
area
relative
to
the
surrounding
before and after IV administration
both
angiography
vessels faint
showed
entering
tumor
a moderately
from
stain
during
hypervascular
the periphery the
liver
of contrast
capillary
during phase.
mass
the arterial MR
Hepatic
with
was
per-
formed with a 1 .5-T Signa imaging system (General Electric Medical Systems, Milwaukee, WI). On Ti -weighted (SE) images, spin-echo 500/20 (TR/TE), the hepatic mass was hyperintense relative to the liver except for the central zone of hypointensity with a hypointense rim (Fig. 1 A). On T2-weighted
images
(SE 2500/80),
the mass
was
hypointense compared with normal liver and its central zone showed hyperintensity. The peripheral rim of the mass was double layered with inner hypointensity and outer hyperintensity (Fig. 1B). slightly
by a thin fibrous
a pseudocapsule
system.
Received March 7, 1990; accepted after revision April 24, 1990. 1 Department of Radiology, School of Medicine, Kanazawa University, 1 3-1 Takara-machi, Kanazawa 2 Department of First Pathology, School of Medicine, Kanazawa University, Kanazawa 920, Japan. 3
Department
of Intemal
4
Department
of Surgery, Kanazawa Red Cross Hospital, Kanazawa 920, Japan.
AJR 155:1009-1011,
Medicine,
November
Kanazawa
Red Cross
1990 0361-803x/90/1555-1009
Hospital,
2-251
Minma,
© American
hypoin-
capsule,
in the medial
segment
composed
The pathologic
of
diagnosis
compressed
normal
was hepatic adenoma
iD).
imaging
and a
was
22/i 3/
markedly
Rummeny
et al. [4] reported
four cases
that
were isointense or slightly hyperintense on Ti -weighted images and hyperintense on T2-weighted images on a 0.6-I MR imaging system. They considered adenoma in many cases to be indistinguishable from HCC on MR images. However, they used midfield superconducting systems (0.35 and 0.6 1), and the images of the cases reported by Moss et al. were not clear and could not be obtained with strictly T2weighted pulse sequences. Conversely, Nokes et al. [5] reported a case of a hepatic adenoma that was nearly isointense relative to normal liver on Ti - and T2-weighted images,
tumor
phase
imaging
was
To our knowledge, few reports have been published about MR imaging of hepatic adenomas [3-5]. Moss et al. [3] reported two cases of hepatic adenomas that were hyperintense on long TR/TE pulse sequences on a 0.35-T MR
parenchyma
medium.
state (GRASS,
Discussion
A sonogram
revealed a single, well-circumscribed mass protruding from the medial segment of the liver, which was slightly hyperechoic with inhomogeneity. CT showed a hypodense mass, 1 0 cm in diameter, with an isodense
into steady of the mass
of the liver. It was partially lobulated and had central hemorrhage (Fig. i C). Histologically, the tumor was composed of normal-sized or slightly larger cells resembling normal hepatocytes arranged in sheets and cords. There were no Kupifer cells or bile ducts within the tumor. The tumor scarcely had fatty metamorphosis within it. The fibrous
Report
ago.
zone
Ueda,2
tense, which we considered to be indicative of central hemorrhage. Resection of the tumor revealed a giant (maximal diameter, 1 1 .5 cm)
adenoma is the specific
A 38-year-old woman had a 2-week history of epigastric nausea. She had taken oral contraceptives for 3 months
Yoshimichi
the central
hepatic parenchyma. Case
Report
Kanazawa
920, Japan.
920, Japan.
Roentgen Ray Society
Address
reprint
requests
to T. Gabata.
1010
GABATA
ET
AL.
AJR:155,
November
1990
Fig.
1.-A, Ti-weighted MR image (SE 500/ tumor is hyperintense relative to liver hypointense zone (arrowheads). Rim is hypointense (arrows). B, T2-weighted MR image (SE 2500/80). Tumor is hypointense relative to liver. Central zone is markedly hyperintense (arrowheads). Peripheral rim of tumor has double layers with inner hypointensity and outer hyperintensity (arrows). C, Resected tumor, sectioned in sagittal plane. Tumor is partially lobulated and encapsulated with thin fibrous capsule (black arrows). Note central hemorrhage (white arrow). GB = gallbladder. D, Microscopic section shows pseudocapsule(P)composed of compressed hepatic portal tract; outside of it, compressed normal hepatic parenchyma is seen. T = tumor, H = hepatic parenchyma.
20). Large
Downloaded from www.ajronline.org by 120.36.151.163 on 11/05/15 from IP address 120.36.151.163. Copyright ARRS. For personal use only; all rights reserved
with central
,,
H
p
#{188}
IF -
“I ..
C
.
-.
.
.,
Li
mimicking focal nodular hyperplasia, which has been reported to show similar intensity relative to normal liver on both pulse sequences [4, 6]. Almost all hepatic tumors, such as hemangioma, metastasis, and cholangiocarcinoma, are seen as hypointense on Ti weighted images and hyperintense on 12-weighted images [3, 4]. It has been reported that 31 % of HCCs are hyperintense on Ti-weighted images, while 97% are hyperintense on 12-weighted images [7]. Hyperintensity of HCC on Ti weighted images was thought to be one of the important characteristics allowing differentiation of HCC from other tumors [7]. Hyperintensity of HCC on Ti -weighted images is generally thought to be related to steatosis of cancer tissue, but we saw many cases of HCC that had increased signal intensity on Ti -weighted images, and scarcely had steatosis histologically (unpublished data). Therefore, any other cause of the increased signal intensity is unknown. Our case of hepatic adenoma, which also scarcely had fatty metamorphosis histologically, was hyperintense on Ti -weighted images, similar to some cases of HCC. However, it was hypointense on T2weighted images, in distinct contrast to HCCs, which are usually hyperintense. So we were able to differentiate our case of adenoma from HCC. Hypointensity on 12-weighted
images is very unusual and has not been reported in any hepatic tumors. Recently we reported that hepatic adenomatous hyperplastic nodules in the cirrhotic liver, which are possibly precancerous lesions of HCC, also show hyperintensity on Ti weighted images and hypointensity on 12-weighted images [8]. Itoh et al. [7] suggested that well-differentiated HCCs tend to show higher intensity on Ti -weighted images. Adenomatous hyperplastic nodules and our case of adenoma, which are all difficult to distinguish from well-differentiated HCC, also show hyperintensity on Ti -weighted images. Therefore, we speculate that benign hepatic tumor composed of cells resembling normal hepatocytes such as focal nodular hyperplasia, adenoma, and adenomatous hyperplastic nodules may be isointense or hypointense on 12-weighted images; these can be differentiated from malignant hepatic tumors, which almost always are hyperintense on 12weighted images. In our case, the adenoma had a hypointense rim on Ti weighted images and a double-layered (inner low intensity and outer high intensity) rim on 12-weighted images. Comparison of the MR images and pathologic findings showed that the inner hypointense rim corresponds to the pseudocapsule and the outer hyperintense rim to the compressed normal
Downloaded from www.ajronline.org by 120.36.151.163 on 11/05/15 from IP address 120.36.151.163. Copyright ARRS. For personal use only; all rights reserved
AJR:155,
November
1990
MR
OF
HEPATIC
hepatic parenchyma. Similar MR findings were reported in HCCs [7]. The central hypointense area of the tumor on GRASS images was related to hemosiderin deposition as a result of hemorrhage. We think that GRASS images are useful in the detection of intratumoral hemorrhage. Our case illustrates that MR can differentiate benign hepatic tumors originating from hepatocytes from malignant tumors on the basis of the intensity pattern, especially on 12weighted images. However, further examinations will be necessary to confirm the usefulness of MR imaging for differentiating hepatic tumors.
ADENOMA
i
oi i
2. Kerlin P, Davis GL, McGill 06, Weiland LH, Adson MA, Sheerly PF. Hepatic adenoma
and focal nodular
hyperplasia:
clinical,
pathologic,
and radiologic
features. Gastroentero/ogy i983;84: 994-1002 3. Moss AA, Goldberg HI, Stark DD, et al. Hepatic tumors: magnetic resonance and CT appearance. Radiology 1984;1 50:141-147 4. Rummeny E, Weissleder R, Stark DO, et al. Primary liver tumor: diagnosis by MR imaging. AiR 1989;152:63-72 5. Nokes SR, Baker ME, Spritzer CE, Meyers W, Herfkens RJ. Hepatic adenoma: MR appearance mimicking focal nodular hyperplasia. J Comput Assist
Tomogr
1988;12:885-887
6. Mattison GR, Glazer GM, Quint LE, Francis IR, Bree RL, Ensminger MR imaging of hepatic focal nodular hyperplasia: characterization distinction
from
primary
malignant
hepatic
tumors.
AJR
WD.
and 1987;148:
711-715 7. Itoh K, Nishimura
K, Togashi K, et al. Hepatocellular carcinoma: MR i987;164:21-25 8. Matsui 0, Kadoya M, Kameyama T, et al. Adenomatous hyperplastic imaging.
REFERENCES 1 . Goodman Neop/asm
ZO. Benign tumor of the liver. Tokyo:
of the liver. In: Okuda K, Ishak Springer, 1987: 105-1 25
KG, eds.
Radiology
nodules in the cirrhotic liver: differentiation from hepatocellular with MR imaging. Radiology 1989;173: 123-1 26
carcinoma
1009
Case
MR Imaging Toshifurni Yoshikazu
of Hepatic
Adenoma
Gabata,1 Osamu Matsui,1 Masurni Kornatsu,3 and Makoto Sasaki4
Kadoya,1
Tsutornu
[3, 4]. The MR appearance and MR has been unable
variable, diagnosis adenoma
of hepatic to provide
Takashima,1
On gradient-recalled
Hepatic adenoma is a rare benign tumor composed of benign hepatocytes in sheets and cords without an acinar architecture [1 ]. It is difficult to distinguish from well-differentiated hepatocellular carcinoma (HCC), both pathologically and radiologically [2]. MR imaging has become an important diagnostic technique for detecting and differentiating hepatic
tumors
1 0#{176} flip
angle),
acquisition
tumor,
in reported cases [3-5]. We report a case of hepatic with a characteristic appearance on MR images.
encapsulated
capsule (Fig.
Results
of physical
examination
were
normal.
pain and 10 years
central
area
relative
to
the
surrounding
before and after IV administration
both
angiography
vessels faint
showed
entering
tumor
a moderately
from
stain
during
hypervascular
the periphery the
liver
of contrast
capillary
during phase.
mass
the arterial MR
Hepatic
with
was
per-
formed with a 1 .5-T Signa imaging system (General Electric Medical Systems, Milwaukee, WI). On Ti -weighted (SE) images, spin-echo 500/20 (TR/TE), the hepatic mass was hyperintense relative to the liver except for the central zone of hypointensity with a hypointense rim (Fig. 1 A). On T2-weighted
images
(SE 2500/80),
the mass
was
hypointense compared with normal liver and its central zone showed hyperintensity. The peripheral rim of the mass was double layered with inner hypointensity and outer hyperintensity (Fig. 1B). slightly
by a thin fibrous
a pseudocapsule
system.
Received March 7, 1990; accepted after revision April 24, 1990. 1 Department of Radiology, School of Medicine, Kanazawa University, 1 3-1 Takara-machi, Kanazawa 2 Department of First Pathology, School of Medicine, Kanazawa University, Kanazawa 920, Japan. 3
Department
of Intemal
4
Department
of Surgery, Kanazawa Red Cross Hospital, Kanazawa 920, Japan.
AJR 155:1009-1011,
Medicine,
November
Kanazawa
Red Cross
1990 0361-803x/90/1555-1009
Hospital,
2-251
Minma,
© American
hypoin-
capsule,
in the medial
segment
composed
The pathologic
of
diagnosis
compressed
normal
was hepatic adenoma
iD).
imaging
and a
was
22/i 3/
markedly
Rummeny
et al. [4] reported
four cases
that
were isointense or slightly hyperintense on Ti -weighted images and hyperintense on T2-weighted images on a 0.6-I MR imaging system. They considered adenoma in many cases to be indistinguishable from HCC on MR images. However, they used midfield superconducting systems (0.35 and 0.6 1), and the images of the cases reported by Moss et al. were not clear and could not be obtained with strictly T2weighted pulse sequences. Conversely, Nokes et al. [5] reported a case of a hepatic adenoma that was nearly isointense relative to normal liver on Ti - and T2-weighted images,
tumor
phase
imaging
was
To our knowledge, few reports have been published about MR imaging of hepatic adenomas [3-5]. Moss et al. [3] reported two cases of hepatic adenomas that were hyperintense on long TR/TE pulse sequences on a 0.35-T MR
parenchyma
medium.
state (GRASS,
Discussion
A sonogram
revealed a single, well-circumscribed mass protruding from the medial segment of the liver, which was slightly hyperechoic with inhomogeneity. CT showed a hypodense mass, 1 0 cm in diameter, with an isodense
into steady of the mass
of the liver. It was partially lobulated and had central hemorrhage (Fig. i C). Histologically, the tumor was composed of normal-sized or slightly larger cells resembling normal hepatocytes arranged in sheets and cords. There were no Kupifer cells or bile ducts within the tumor. The tumor scarcely had fatty metamorphosis within it. The fibrous
Report
ago.
zone
Ueda,2
tense, which we considered to be indicative of central hemorrhage. Resection of the tumor revealed a giant (maximal diameter, 1 1 .5 cm)
adenoma is the specific
A 38-year-old woman had a 2-week history of epigastric nausea. She had taken oral contraceptives for 3 months
Yoshimichi
the central
hepatic parenchyma. Case
Report
Kanazawa
920, Japan.
920, Japan.
Roentgen Ray Society
Address
reprint
requests
to T. Gabata.
1010
GABATA
ET
AL.
AJR:155,
November
1990
Fig.
1.-A, Ti-weighted MR image (SE 500/ tumor is hyperintense relative to liver hypointense zone (arrowheads). Rim is hypointense (arrows). B, T2-weighted MR image (SE 2500/80). Tumor is hypointense relative to liver. Central zone is markedly hyperintense (arrowheads). Peripheral rim of tumor has double layers with inner hypointensity and outer hyperintensity (arrows). C, Resected tumor, sectioned in sagittal plane. Tumor is partially lobulated and encapsulated with thin fibrous capsule (black arrows). Note central hemorrhage (white arrow). GB = gallbladder. D, Microscopic section shows pseudocapsule(P)composed of compressed hepatic portal tract; outside of it, compressed normal hepatic parenchyma is seen. T = tumor, H = hepatic parenchyma.
20). Large
Downloaded from www.ajronline.org by 120.36.151.163 on 11/05/15 from IP address 120.36.151.163. Copyright ARRS. For personal use only; all rights reserved
with central
,,
H
p
#{188}
IF -
“I ..
C
.
-.
.
.,
Li
mimicking focal nodular hyperplasia, which has been reported to show similar intensity relative to normal liver on both pulse sequences [4, 6]. Almost all hepatic tumors, such as hemangioma, metastasis, and cholangiocarcinoma, are seen as hypointense on Ti weighted images and hyperintense on 12-weighted images [3, 4]. It has been reported that 31 % of HCCs are hyperintense on Ti-weighted images, while 97% are hyperintense on 12-weighted images [7]. Hyperintensity of HCC on Ti weighted images was thought to be one of the important characteristics allowing differentiation of HCC from other tumors [7]. Hyperintensity of HCC on Ti -weighted images is generally thought to be related to steatosis of cancer tissue, but we saw many cases of HCC that had increased signal intensity on Ti -weighted images, and scarcely had steatosis histologically (unpublished data). Therefore, any other cause of the increased signal intensity is unknown. Our case of hepatic adenoma, which also scarcely had fatty metamorphosis histologically, was hyperintense on Ti -weighted images, similar to some cases of HCC. However, it was hypointense on T2weighted images, in distinct contrast to HCCs, which are usually hyperintense. So we were able to differentiate our case of adenoma from HCC. Hypointensity on 12-weighted
images is very unusual and has not been reported in any hepatic tumors. Recently we reported that hepatic adenomatous hyperplastic nodules in the cirrhotic liver, which are possibly precancerous lesions of HCC, also show hyperintensity on Ti weighted images and hypointensity on 12-weighted images [8]. Itoh et al. [7] suggested that well-differentiated HCCs tend to show higher intensity on Ti -weighted images. Adenomatous hyperplastic nodules and our case of adenoma, which are all difficult to distinguish from well-differentiated HCC, also show hyperintensity on Ti -weighted images. Therefore, we speculate that benign hepatic tumor composed of cells resembling normal hepatocytes such as focal nodular hyperplasia, adenoma, and adenomatous hyperplastic nodules may be isointense or hypointense on 12-weighted images; these can be differentiated from malignant hepatic tumors, which almost always are hyperintense on 12weighted images. In our case, the adenoma had a hypointense rim on Ti weighted images and a double-layered (inner low intensity and outer high intensity) rim on 12-weighted images. Comparison of the MR images and pathologic findings showed that the inner hypointense rim corresponds to the pseudocapsule and the outer hyperintense rim to the compressed normal
Downloaded from www.ajronline.org by 120.36.151.163 on 11/05/15 from IP address 120.36.151.163. Copyright ARRS. For personal use only; all rights reserved
AJR:155,
November
1990
MR
OF
HEPATIC
hepatic parenchyma. Similar MR findings were reported in HCCs [7]. The central hypointense area of the tumor on GRASS images was related to hemosiderin deposition as a result of hemorrhage. We think that GRASS images are useful in the detection of intratumoral hemorrhage. Our case illustrates that MR can differentiate benign hepatic tumors originating from hepatocytes from malignant tumors on the basis of the intensity pattern, especially on 12weighted images. However, further examinations will be necessary to confirm the usefulness of MR imaging for differentiating hepatic tumors.
ADENOMA
i
oi i
2. Kerlin P, Davis GL, McGill 06, Weiland LH, Adson MA, Sheerly PF. Hepatic adenoma
and focal nodular
hyperplasia:
clinical,
pathologic,
and radiologic
features. Gastroentero/ogy i983;84: 994-1002 3. Moss AA, Goldberg HI, Stark DD, et al. Hepatic tumors: magnetic resonance and CT appearance. Radiology 1984;1 50:141-147 4. Rummeny E, Weissleder R, Stark DO, et al. Primary liver tumor: diagnosis by MR imaging. AiR 1989;152:63-72 5. Nokes SR, Baker ME, Spritzer CE, Meyers W, Herfkens RJ. Hepatic adenoma: MR appearance mimicking focal nodular hyperplasia. J Comput Assist
Tomogr
1988;12:885-887
6. Mattison GR, Glazer GM, Quint LE, Francis IR, Bree RL, Ensminger MR imaging of hepatic focal nodular hyperplasia: characterization distinction
from
primary
malignant
hepatic
tumors.
AJR
WD.
and 1987;148:
711-715 7. Itoh K, Nishimura
K, Togashi K, et al. Hepatocellular carcinoma: MR i987;164:21-25 8. Matsui 0, Kadoya M, Kameyama T, et al. Adenomatous hyperplastic imaging.
REFERENCES 1 . Goodman Neop/asm
ZO. Benign tumor of the liver. Tokyo:
of the liver. In: Okuda K, Ishak Springer, 1987: 105-1 25
KG, eds.
Radiology
nodules in the cirrhotic liver: differentiation from hepatocellular with MR imaging. Radiology 1989;173: 123-1 26
carcinoma
