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Lipoma of the falciform ligament: US, CT, and MRI appearances
CLINICAL
IMAGING
1993;17:27-29
27
LIPOMA OF THE FALCIFORM LIGAMENT: US, CT, AND MRI APPEARANCES YOUSUKE KAKITSUBATA, MD, RUMIKO NAKAMURA, TORU SHIBA, MD, HIROSHI SUGIMURA, MD, YUKIKO SUZUKI, MD, SACHIKO KAKITSUBATA, MD, KATSUSHI WATANABE, MD, TAKASHI KAWANA, MD, AND TAKASHI IWAMURA, MD
A case of Iipoma of the falciform ligament was demonstrated using computed tomography (CT), ultrasonography (US), and magnetic resonance imaging (MRI). US demonstrated a heterogeneous solid mass anteriorly in the upper portion of the abdomen. CT and MRI revealed a solitary, fatty mass with a small amount of soft tissue in it. KEY WORDS:
Lipoma; Falciform ligament; Ultrasonography; tomography; Magnetic resonance imaging
Computed
Lipomas are common neoplasms of the abdomen. However, lipomas that arise from the falciform ligament appear to be very rare (1-Z). This is a report of a case with characteristic findings on computed tomography (CT) and magnetic resonance imaging (MRI). To our knowledge, this is the first description of the MR appearance of a lipoma of the falciform ligament. CASE REPORT A 56-year-old man was admitted to Miyazaki Medical College Hospital for a polypectomy of the colon. His physical examination and laboratory findings on ad-
From the Department of Radiology (Y .K., R.N., T.S., H.S., Y S., S.K., K.W.), and the First Department of Surgery (T.K., T.I.), Miyazaki Medical College, Miyazaki, Japan. Address reprint requests to: Yousuke Kakitsubata, MD, Department of Radiology, Miyazaki Medical College, 5200 Kiyotake, Miyazaki, 889-16, Japan. Received March 11, 1992. Q 1993 by Elsevier Science Publishing Co., Inc.
655 Avenue of the Americas, 0899.7071/93/$6.00
New York, NY 10010
MD,
mission were normal. Barium enema studies showed a small polypoid lesion in his sigmoid colon. Ultrasonography (US) during a tumor work-up incidentally demonstrated a heterogeneous solid mass anteriorly in the upper portion of the abdomen, which measured 7 x 3 x 9 cm3 (Figure 1). The lesion was relatively hypoechoic, had smooth borders, and it displaced the stomach. The tumor’s shape changed readily on compression. Precontrast CT revealed a solitary mass of fat density (-95 HU) (Figure 2). There was a small amount of soft tissue in the tumor. This mass of fat density was not enhanced by injected contrast material. Its mass effect on the adjacent structures, particularly the stomach, was noted. MRI disclosed the lesion to be heterogeneous and hyperintense on all spin-echo pulse sequences used (Tl-
FIGURE
1. A transverse sonogram of the upper portion of the abdomen shows a well-demarcated, heterogeneous, hypoechoic mass.
28
KAKITSUBATA
ET AL.
CLINICAL IMAGING VOL. 17, NO. 1
of the abdomen. The tumor was well encapsulated and tumor vessels arising from the falciform ligament near the abdominal wall were detected. There were no inflammatory changes or adhesions in the adjacent organs. The diagnosis of a suspected lipoma was confirmed histologically. The patient recovered uneventfully.
FIGURE 2. Precontrast CT image through the tumor reveals a solitary mass of fat density (-95 HU) between the liver and stomach. There is a small component of soft tissue in the tumor.
T&weighted, and proton densityweighted, weighted) (Figure 3). An angiogram showed a hypovascular mass without tumor stains. Angiographitally, the origin of the tumor was considered to be the greater omentum. Surgical exploration disclosed a yellowish, lobulated, 8 x 8 x 4 cm3 mass in the anterior portion
FIGURE 3. (A) Axial, Tl-weighted (1.5-T, TR = 0.6 set, TE = 13 msec) MRI shows a hyperintense mass anterior to the pancreatic body. (B) Axial, T2-weighted (TR = 2.0 set, TE = 80 msec) MRI shows a relatively hyperintense mass with signal characteristics similar to those of overlying subcutaneous fat. (C) Sagittal, Tl-weighted MRI shows a hyperintense mass beneath the left lobe of the liver.
JANUARY-MARCH
1993
DISCUSSION Lipoma is one of the most common mesenchymal tumors, with a broad distribution throughout the body. However, lipoma of the falciform ligament is extremely rare, and few cases have been reported (l-2). In our case, the tumor was present anteriorly in the abdomen below the lateral segment of the liver, and originating from the falciform ligament on the anterior abdominal wall. No invasion of adjacent structures was identified. On US, lipoma is usually a homogeneous, hyperechoic, well-demarcated mass. However, it sometimes is a heterogeneous, isoechoic mass. In our case, US revealed a relatively hypoechoic, heterogeneous mass in the anterior portion of the abdomen. The present case was initially interpreted by US as being a leiomyoma or leiomyosarcoma of the greater omentum. Lipoma is easily diagnosed by CT, which shows a well-encapsulated, homogeneous mass of fat density. Lipoma can be diagnosed when densitometric analysis yields negative CT numbers and no tumor contrast enhancement (3, 4). However, it may be difficult to differentiate lipoma from liposarcoma when there is an extensive soft-tissue component in the tumor. Enhancement in such a situation would have raised the possibility of malignancy (5). In our case, CT showed a relatively homogeneous mass of fat density, without invasive changes. MRI findings of patients with lipomas of the falciform ligament have not been reported. Lipomas pres-
LIPOMA
OF THE FALCIFORM
LIGAMENT
29
ent as homogeneous, well-demarcated masses with the same signal intensities as subcutaneous adipose tissue on both Tl-weighted, and TZ-weighted spinecho images (6). However, differentiating between a lipoma and an old hematoma may be difficult based on intensities. Although it is necessary to use chemical shift imaging with MRI, US and CT are available for such discrimination. In conclusion, lipoma of the falciform ligament is a rare tumor of the abdomen that can be easily diagnosed by CT. MRI can also show the characteristic findings of lipomas and provides an excellent means of evaluating the extent of these tumors. REFERENCES Watanabe K, Mihara K, Hoshi H, SakihamaM. 1. HondaH, of the hepatic falciform ligament. J Comput Assist 1983;7:170. 2. Bruneton
Santini graphic
Lipoma Tomogr
JN, Kerboul P, Drouillard J, Menu Y, Normand F, N. Hepatic tumors: ultrasound and computed tomofindings. Gastrointest Radio1 1987;12:299-303.
tu3. Dooms GC, Hricak H, Sollito RA, Higgins CB. Lipomatous mors and tumors with fatty component: MR imaging potential and comparison of MR and CT results. Radiology 1985;157: 479-483. 4. Hubener KH, Hippeli 1980;133:176-179.
R. Das Leberlipom.
5. Friedman AC, Hartman M. Computed tomography 1981;139:415-429.
DS, Sherman of abdominal
6. Bloom RA, Gomori JM, Fields poma: CT and MRI appearance. 1991;15:37-39.
Fortschr
Roentgenstr
J, Lautin EM, Goldman fatty masses. Radiology
SI, Katz E. Abdominal wall liComput Med Imaging Graph
IMAGING
1993;17:27-29
27
LIPOMA OF THE FALCIFORM LIGAMENT: US, CT, AND MRI APPEARANCES YOUSUKE KAKITSUBATA, MD, RUMIKO NAKAMURA, TORU SHIBA, MD, HIROSHI SUGIMURA, MD, YUKIKO SUZUKI, MD, SACHIKO KAKITSUBATA, MD, KATSUSHI WATANABE, MD, TAKASHI KAWANA, MD, AND TAKASHI IWAMURA, MD
A case of Iipoma of the falciform ligament was demonstrated using computed tomography (CT), ultrasonography (US), and magnetic resonance imaging (MRI). US demonstrated a heterogeneous solid mass anteriorly in the upper portion of the abdomen. CT and MRI revealed a solitary, fatty mass with a small amount of soft tissue in it. KEY WORDS:
Lipoma; Falciform ligament; Ultrasonography; tomography; Magnetic resonance imaging
Computed
Lipomas are common neoplasms of the abdomen. However, lipomas that arise from the falciform ligament appear to be very rare (1-Z). This is a report of a case with characteristic findings on computed tomography (CT) and magnetic resonance imaging (MRI). To our knowledge, this is the first description of the MR appearance of a lipoma of the falciform ligament. CASE REPORT A 56-year-old man was admitted to Miyazaki Medical College Hospital for a polypectomy of the colon. His physical examination and laboratory findings on ad-
From the Department of Radiology (Y .K., R.N., T.S., H.S., Y S., S.K., K.W.), and the First Department of Surgery (T.K., T.I.), Miyazaki Medical College, Miyazaki, Japan. Address reprint requests to: Yousuke Kakitsubata, MD, Department of Radiology, Miyazaki Medical College, 5200 Kiyotake, Miyazaki, 889-16, Japan. Received March 11, 1992. Q 1993 by Elsevier Science Publishing Co., Inc.
655 Avenue of the Americas, 0899.7071/93/$6.00
New York, NY 10010
MD,
mission were normal. Barium enema studies showed a small polypoid lesion in his sigmoid colon. Ultrasonography (US) during a tumor work-up incidentally demonstrated a heterogeneous solid mass anteriorly in the upper portion of the abdomen, which measured 7 x 3 x 9 cm3 (Figure 1). The lesion was relatively hypoechoic, had smooth borders, and it displaced the stomach. The tumor’s shape changed readily on compression. Precontrast CT revealed a solitary mass of fat density (-95 HU) (Figure 2). There was a small amount of soft tissue in the tumor. This mass of fat density was not enhanced by injected contrast material. Its mass effect on the adjacent structures, particularly the stomach, was noted. MRI disclosed the lesion to be heterogeneous and hyperintense on all spin-echo pulse sequences used (Tl-
FIGURE
1. A transverse sonogram of the upper portion of the abdomen shows a well-demarcated, heterogeneous, hypoechoic mass.
28
KAKITSUBATA
ET AL.
CLINICAL IMAGING VOL. 17, NO. 1
of the abdomen. The tumor was well encapsulated and tumor vessels arising from the falciform ligament near the abdominal wall were detected. There were no inflammatory changes or adhesions in the adjacent organs. The diagnosis of a suspected lipoma was confirmed histologically. The patient recovered uneventfully.
FIGURE 2. Precontrast CT image through the tumor reveals a solitary mass of fat density (-95 HU) between the liver and stomach. There is a small component of soft tissue in the tumor.
T&weighted, and proton densityweighted, weighted) (Figure 3). An angiogram showed a hypovascular mass without tumor stains. Angiographitally, the origin of the tumor was considered to be the greater omentum. Surgical exploration disclosed a yellowish, lobulated, 8 x 8 x 4 cm3 mass in the anterior portion
FIGURE 3. (A) Axial, Tl-weighted (1.5-T, TR = 0.6 set, TE = 13 msec) MRI shows a hyperintense mass anterior to the pancreatic body. (B) Axial, T2-weighted (TR = 2.0 set, TE = 80 msec) MRI shows a relatively hyperintense mass with signal characteristics similar to those of overlying subcutaneous fat. (C) Sagittal, Tl-weighted MRI shows a hyperintense mass beneath the left lobe of the liver.
JANUARY-MARCH
1993
DISCUSSION Lipoma is one of the most common mesenchymal tumors, with a broad distribution throughout the body. However, lipoma of the falciform ligament is extremely rare, and few cases have been reported (l-2). In our case, the tumor was present anteriorly in the abdomen below the lateral segment of the liver, and originating from the falciform ligament on the anterior abdominal wall. No invasion of adjacent structures was identified. On US, lipoma is usually a homogeneous, hyperechoic, well-demarcated mass. However, it sometimes is a heterogeneous, isoechoic mass. In our case, US revealed a relatively hypoechoic, heterogeneous mass in the anterior portion of the abdomen. The present case was initially interpreted by US as being a leiomyoma or leiomyosarcoma of the greater omentum. Lipoma is easily diagnosed by CT, which shows a well-encapsulated, homogeneous mass of fat density. Lipoma can be diagnosed when densitometric analysis yields negative CT numbers and no tumor contrast enhancement (3, 4). However, it may be difficult to differentiate lipoma from liposarcoma when there is an extensive soft-tissue component in the tumor. Enhancement in such a situation would have raised the possibility of malignancy (5). In our case, CT showed a relatively homogeneous mass of fat density, without invasive changes. MRI findings of patients with lipomas of the falciform ligament have not been reported. Lipomas pres-
LIPOMA
OF THE FALCIFORM
LIGAMENT
29
ent as homogeneous, well-demarcated masses with the same signal intensities as subcutaneous adipose tissue on both Tl-weighted, and TZ-weighted spinecho images (6). However, differentiating between a lipoma and an old hematoma may be difficult based on intensities. Although it is necessary to use chemical shift imaging with MRI, US and CT are available for such discrimination. In conclusion, lipoma of the falciform ligament is a rare tumor of the abdomen that can be easily diagnosed by CT. MRI can also show the characteristic findings of lipomas and provides an excellent means of evaluating the extent of these tumors. REFERENCES Watanabe K, Mihara K, Hoshi H, SakihamaM. 1. HondaH, of the hepatic falciform ligament. J Comput Assist 1983;7:170. 2. Bruneton
Santini graphic
Lipoma Tomogr
JN, Kerboul P, Drouillard J, Menu Y, Normand F, N. Hepatic tumors: ultrasound and computed tomofindings. Gastrointest Radio1 1987;12:299-303.
tu3. Dooms GC, Hricak H, Sollito RA, Higgins CB. Lipomatous mors and tumors with fatty component: MR imaging potential and comparison of MR and CT results. Radiology 1985;157: 479-483. 4. Hubener KH, Hippeli 1980;133:176-179.
R. Das Leberlipom.
5. Friedman AC, Hartman M. Computed tomography 1981;139:415-429.
DS, Sherman of abdominal
6. Bloom RA, Gomori JM, Fields poma: CT and MRI appearance. 1991;15:37-39.
Fortschr
Roentgenstr
J, Lautin EM, Goldman fatty masses. Radiology
SI, Katz E. Abdominal wall liComput Med Imaging Graph