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Primary malignant fibrous histiocytoma of the liver MRI findings
Magnetic Resonance Imaging, Vol. 1I,pp.139-143, 1993 Printed in the USA. All rights reserved.
Copyright 0
0730-725X193 $503 + .CKl 1992 Pergamon Press Ltd.
0 Case Report PRIMARY
JONATHAN Departments
G.
MALIGNANT FIBROUS HISTIOCYTOMA OF THE LIVER MRI FINDINGS
REED,*
PHILIP
GOODMAN,?
AND ROGER
D. SOLOWAY$
*Department of Radiology at San Jacinto Methodist Hospital, Baytown, TX 77521, USA, of TRadiology and $Internal Medicine, University of Texas Medical Branch, Galveston, TX 77550, USA
Primary malignant fibrous histiocytoma (MFH) is an unusual tumor which involves the deep fascia or skeletal muscles of the extremities or retroperitoneum. It rarely arises in the liver and, to our knowledge, the MRI appearance of primary MFH of the liver has never been reported. We present a patient with primary MFH of the liver and discuss the findings on MRI, CT, and angiography. Keywords:
Malignant
fibrous histiocytoma;
Pleomorphic
sarcoma; Liver MRI studies.
tions and mural nodules. Associated inflammatory change/infiltration was present in the right pericolic gutter with thickening of the lateral conal fascia. There was presumptive evidence of invasion of the right kidney because the expected distinct tissue plane between the mass and the kidney was absent. Gerota’s fascia was thickened and spiculated on several images. No appreciable contrast enhancement of the mass was detected (Fig. lA,B). No other masses or evidence of lymphadenopathy were present in the abdomen, pelvis and retroperitoneum. It therefore represented a primary liver tumor. An arteriogram and hepatic venogram showed a hypovascular mass displacing hepatic arteries and veins. MRI images obtained with a 0.6 T Teslacon scanner revealed a large lobulated encapsulated mass of heterogeneous signal intensity on both Tl and T2 images. The MRI mixed signals reflected hemorrhage necrosis and inflammation that correlates with the change in water content that occurs with the breakdown of normal tissue architecture in necrotic tumors. The actual neoplasm became brighter as T2 was lengthened (Figs. 2A-C). At surgery, tumor-mass extended from the right lobe of the liver into the right adrenal gland and the margin of the left lobe of the liver, but spared the right kidney. No tumor metastasis outside the liver, includ-
INTRODUCTION Primary malignant fibrous histiocytoma (MFH) is an unusual tumor which involves the deep fascia or skeletal muscles of the extremities or retroperitoneum. It rarely arises in the liver and, to our knowledge, the MRI appearance of primary MFH of the liver has never been reported. Of particular interest is the MRI appearance of this tumor compared with that of other liver tumors. Primary liver MFH resembles hypovascular hepatoma with extensive areas of necrosis, and has no other distinguishing features other than those of a malignancy. It is interesting that the tumor capsule was visible on MRI but not CT, and that tumor margins were better visualized with MRI than with CT. CASE REPORT A 52-year-old man was admitted from an outlying hospital. Enterococcus and “myxoma-like” cells were found in drainage material from a percutaneous liver catheter. His temperature continued to spike to 105°F despite appropriate antibiotic coverage. His white blood cell count was 19,000, and hematocrit 25%. A contrast-enhanced CT scan of the abdomen demonstrated a large mass extending from the right lobe of the liver. The mass was inhomogeneous and contained a large fluid density component with multiple septal/31/92; ACCEPTED 6114192. Address correspondence to Jonathan G. Reed, MD, De-
partment
RECEIVED
of Radiology,
4401 Garth Road, 139
San Jacinto Methodist Hospital,
Baytown,
TX 77521.
140
Magnetic Resonance Imaging 0 Volume
(A)
11,
Number 1, 1993
(W
Fig. 1. (A) CT scan shows a large hepatic mass containing extensive necrosis. A tumor capsule is not clearly identified. CT scan shows possible invasion of the right kidney by the hepatic mass (arrow).
ing the subhepatic space, were discovered during the laparotomy. A right hepatic lobectomy was performed. Pathological analysis of the specimen revealed an extensively necrotic tumor separated from com-
Fig. 2(A). NSQ = 6,7 sent tumor, bile during
(B)
pressed normal liver tissue by a focally penetrated fibrous capsule (Fig. 3). The tumor was composed of thin-to-plump spindle cells with slightly myxoid, more compact storiform, and hemangiopericytoma-like ar-
7’r weighted spin echo image (TR 312, TE 16, TI = 0, EN = l/l, SN = 11/12, YFOV = 31.0, XFOV = 82.0, mm, Zofs = 8.22, Tipang = 90, Mag = 1.1114, C = 196, W = 423) shows focal dark and light areas which reprenecrosis, and hemorrhage. The gallbladder demonstrates bright signal due to shortening of r, relaxation time of fasting. ‘s2
Primary malignant fibrous histiocytoma 0
J.G. REED ET AL.
141
eas. These features were consistent with malignant fibrous histiocytoma. Despite chemotherapy, the patient developed extensive brain and lung metastases and died 2 mo after surgery. DISCUSSION
Fig. 2(B). Sagittal images (spin echo TR 300, TE 15, TI = 0, EN = l/l, SN = 9/12, YFOV = 82.0, XFOV = 31.0, NSQ = 8, 7 mm, Zofs = 6.36, Tipang = 90.0, Mag = 1 .O, C = 153, W = 25 1) add significantly to the transaxial views in demonstrating noninvolvement of the right kidney. A tissue plane (large arrow) separates tumor from kidney. Tumor encapsulation is also noted @ma11 arrow).
MFH is the most common sarcoma in the soft tissues.3 It originates from undifferentiated mesenchyma1 cells with differentiation into variable portions of fibroblastic and histiocytic cells.4 Immunoperoxidase studies performed on our patient were interpreted as having no evidence of differentiation toward an epithelial, muscle, nerve, or vascular cell type, thus excluding carcinoma, leiomyosarcoma, neurosarcoma, and angiosarcoma. Markers for vimentin, actin, alpha-l, antichymotrypsin, and alpha-1-antitrypsin indicate that sarcomatous, fibrous, myofibroblastic, and histiocytic differentiation were present. Electron microscopy showed features typical of mesenchymal cells of a pleomorphic sarcoma rather than the rare pseudosarcomatous hepatocellular carcinoma.’ Past CT reports of MFH of the liver described a poorly circumscribed, large avascular mass with central necrosis,6-g which is similar to the CT in our patient. The liver arteriogram appearance was also typical of previously reported descriptions of liver MFH.‘O A few corkscrew tumor vessels were identi-
Fig. 2(C). Transaxial image (TR2000, TE150, TI = 0, EN = 2/2, SN = 6/12, YFOV = 31.0, XFOV = 164, NSQ = 4, 12.0 mm, Zofs = 0.20, Mag = 1.114, Tipang = 90, C = 173, W = 369) showing excellent contrast. The blurriness results from the progressive loss of signal with increasing TE.
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Magnetic Resonance Imaging 0 Volume 11, Number 1, 1993
Fin. 3. Gross specimen.
The brown-tan tumor mass (short arrow) weighing 1,450 g contains areas of fluctuance and hemorrhage (long arrow) and is mostly necrotic.
fied near the diaphragmatic surface. No tumor stain was present. The MRI appearance of liver MFH can be conjectured from the MRI appearance of other liver tumors and from the MRI appearance of MFH in other organs. Some CT criteria can be directly applied to MRI. Demarcated borders are usually a sign of benignancy, whereas irregular borders usually indicate malignancy. Infiltration and invasion of surrounding organs also indicate malignancy. With CT, benign soft-tissue masses have a uniform density, whereas malignant lesions often contain areas of decreased density due to hemorrhage and necrosis.” On MRI, uniformity of signal on T2-weighted images is a reliable indication of benignancy in the liver, but lack of uniformity does not reliably indicate malignancy.” A review of the MRI appearance of MFH in extrahepatic locations showed that 88% of such tumors had intermediate signal intensity (equal to surrounding muscles) on T,weighted images and 92% had high signal intensity (equal to or higher than subcutaneous fat) on T2weighted images. All tumors were heterogenous on T,-weighted images, with irregular areas of extremely high and low signals representing areas of hemorrhage
and necrosis.” The MRI appearance of MFH of the liver in our patient is similar to the MRI description of MFH in extrahepatic locations. Necrotic cancers nearly always show evidence of hemorrhage. It is not possible to distinguish fluid within a necrotic tumor that is caused by liquefaction of tissue due to autolysis, from fluid caused by bacterial putrification, or from fluid caused by edema. As liquefaction necrosis becomes more confluent, the core demonstrates a lengthening of Tl and T2 relaxation times.13 MR is more sensitive than CT to changes in water content. Necrotic tumors behave like other fluidcontaining structures since T, and T2 relaxation times correlate closely with water content and the breakdown of normal tissue architecture. The brighter T2 signals originate from areas with greater water content and methemoglobin. The darker signals are from areas with less water content and hemosiderin. The term mosaic pattern used to describe the hepatocellular carcinoma “tumor within tumor” appearance on the cut surface of a pathological specimen could be applied here because of the complex pattern on MRl.14 In our patient, tumor encapsulation is evident on the MRI scan and is not apparent on the CT scan. The
Primary malignant fibrous histiocytoma 0 J.G.
pseudocapsule is most apparent on TI images. Many slow-growing types of hepatoma are frequently surrounded by a fibrous capsule. Ebara claims that MRI is twice as sensitive as CT at demonstrating a “ring sign” (fibrous capsule), highly diagnostic of hepatocellular carcinoma, and that no other hepatic mass lesions have this structure.‘5 Evidence that our case represents a primary liver tumor rather than metastasis is that repeated CT scans, MRI and surgery failed to reveal any retroperitoneal mass. Also, retroperitoneal MFH typically displaces but does not invade abdominal organs,16 and liver metastases from extrahepatic intraperitoneal MFH do not occur until a late stage. ” By the time liver metastasis occur from an extrahepatic primary source, the primary becomes very large and therefore the primary location would be easy to discover. Fever and leukocytosis are unusual manifestations of extrahepatic MFH. l1 Of the six cases of primary MFH of the liver reported in the literature,6-9v18 the presence of elevated white blood cell count or fever, or both was mentioned in three cases. In a fourth case, although the author did not mention it, there is reason to suspect that fever and/or elevated white blood cell count were present because an intense inflammatory response was described several times in the discussion of the histology. I8 In two other cases,9 whether or not fever and elevated white blood cell count were present was not discussed. It might be true that liver MFH is more likely to present with fever and elevated white blood cell count than in MFH elsewhere in the body because liver MFH is a deep, bulky, extensively necrotic lesion that is generally not discovered until it is advanced.’ It has been postulated that bulky liver tumors are associated with liver superinfection because the liver constantly filters bacteria from the gut and the liver tumor functions as an obstruction to that filtering mechanism. REFERENCES Hricak, H.; Filly, R.A.; Margeilis, A.R.; et al. Work in progress nuclear magnetic resonance imaging of the gallbladder. Radiology 147:481-484; 1983. Demas, B.E.; Hricak, H.; Moseley, M. Gallbladder bile: An experimental study in dogs using MR imaging and proton spectroscopy. Radiology 157:453-455; 1985. Enzinger, F.M.; Weiss, S.W. Soft Tissue Tumors. St. Louis: CV Mosby Co.; 1983:~~. 66-198.
REED ET AL.
143
4. Weiss, S.W.; Enzinger, EM. Malignant fibrous histiocytoma. An analysis of 200 cases. Cancer 41:2250-2266; 1978. Pathology of the Cell 5. Ghadially, EN. Ultrastructural and Matrix, 3rd ed., vol. 2. London: Butterworths; 1988: pp. 1112-1125. 6. Honda, H.; Nakemura, Y.; Kajiwara, T.; et al. Malignant fibrous histiocytoma of the liver. Comp. Med. Zmaging Graph. 12(2):131-134; 1988. 7. Alberti-Flor, J.J.; O’Hara, M.F.; Weaver, F.; Evans, J.; McClure, R.; Dunn, G.D. Malignant fibrous histiocytoma of the liver. Gastroenterology 89:890-893; 1985. 8. Conran, R.M.; Stocker, J.T. Malignant fibrous histiocytoma of the liver-a case report. Am. J. Gastroenterol. 80(10):813-815; 1985. A.; Laur9. Bruneton, J.N.; Drouillard, J.; Rogopoulos, ent, F.; Normand, F.; Balu-Maestro, L.; Monticelli, J. Extraretroperitoneal abdominal malignant fibrous histiocytoma. Gastrointestinal Radiology 13:299-305; 1988. features of 10. Burgener, EA.; Landman, S. Angiographic malignant fibrous histiocytoma. Radiology 121:581-538; 1976. J.P.; Turner, D.A.; Charters, S.G.; 11. Petasnick, Zacharias, C.E. Soft tissue masses of the locomotor system: comparison of MRImaging with C.T. Radiology 160:125-133; 1986. 12. Mahajan, H.; Kim, E.E.; Wallace, S.; Abello, R.; Benjamin, R.; Evans, H.L. Magnetic resonance imaging of malignant fibrous histiocytoma. Magn. Reson. Imaging 7:283-288; 1989. diseases. In: D.D. 13. Sze, G. Infections and inflammatory Stark, W.G. Bradley (Eds). Magnetic Resonance Imaging. St. Louis: CV Mosby Co.; 1988:~~. 318-319. K.; Furui, S.; Minami, M.; 14. Itai, Y.; Ohtomo, Yoshikawa, K.; Yashiro, N. MRImaging of hepatocellular carcinoma. J. Comput. Assist. Tomogr. 10(6):963968; 1986. 15. Ebara, M.; Ohto, M.; Watanabe, Y.; et al. Diagnosis of small hepatocellular carcinoma: Correlation of M.R. imaging and tumor histologic studies. Radiology 159:371377; 1986. 16. Ros, P.R.; Viamonte, M.; Rywlin, A.M. Review, malignant fibrous histiocytoma: mesenchymal tumor of ubiquitous origin. AJR 142:753-759; 1984. D.; Waxman, J.S.; Janelli, 17. Waxman, M.; Falgenburg, D.E. Malignant fibrous histiocytoma of the colon associated with diverticulitis. Dis. Colon Rectum 26:339343; 1983. 18. Fukayama, M.; Kaike, M. Malignant fibrous histiocytoma arising in the liver. Arch Pathol. Lab Med. 110: 203-206; 1986.
Copyright 0
0730-725X193 $503 + .CKl 1992 Pergamon Press Ltd.
0 Case Report PRIMARY
JONATHAN Departments
G.
MALIGNANT FIBROUS HISTIOCYTOMA OF THE LIVER MRI FINDINGS
REED,*
PHILIP
GOODMAN,?
AND ROGER
D. SOLOWAY$
*Department of Radiology at San Jacinto Methodist Hospital, Baytown, TX 77521, USA, of TRadiology and $Internal Medicine, University of Texas Medical Branch, Galveston, TX 77550, USA
Primary malignant fibrous histiocytoma (MFH) is an unusual tumor which involves the deep fascia or skeletal muscles of the extremities or retroperitoneum. It rarely arises in the liver and, to our knowledge, the MRI appearance of primary MFH of the liver has never been reported. We present a patient with primary MFH of the liver and discuss the findings on MRI, CT, and angiography. Keywords:
Malignant
fibrous histiocytoma;
Pleomorphic
sarcoma; Liver MRI studies.
tions and mural nodules. Associated inflammatory change/infiltration was present in the right pericolic gutter with thickening of the lateral conal fascia. There was presumptive evidence of invasion of the right kidney because the expected distinct tissue plane between the mass and the kidney was absent. Gerota’s fascia was thickened and spiculated on several images. No appreciable contrast enhancement of the mass was detected (Fig. lA,B). No other masses or evidence of lymphadenopathy were present in the abdomen, pelvis and retroperitoneum. It therefore represented a primary liver tumor. An arteriogram and hepatic venogram showed a hypovascular mass displacing hepatic arteries and veins. MRI images obtained with a 0.6 T Teslacon scanner revealed a large lobulated encapsulated mass of heterogeneous signal intensity on both Tl and T2 images. The MRI mixed signals reflected hemorrhage necrosis and inflammation that correlates with the change in water content that occurs with the breakdown of normal tissue architecture in necrotic tumors. The actual neoplasm became brighter as T2 was lengthened (Figs. 2A-C). At surgery, tumor-mass extended from the right lobe of the liver into the right adrenal gland and the margin of the left lobe of the liver, but spared the right kidney. No tumor metastasis outside the liver, includ-
INTRODUCTION Primary malignant fibrous histiocytoma (MFH) is an unusual tumor which involves the deep fascia or skeletal muscles of the extremities or retroperitoneum. It rarely arises in the liver and, to our knowledge, the MRI appearance of primary MFH of the liver has never been reported. Of particular interest is the MRI appearance of this tumor compared with that of other liver tumors. Primary liver MFH resembles hypovascular hepatoma with extensive areas of necrosis, and has no other distinguishing features other than those of a malignancy. It is interesting that the tumor capsule was visible on MRI but not CT, and that tumor margins were better visualized with MRI than with CT. CASE REPORT A 52-year-old man was admitted from an outlying hospital. Enterococcus and “myxoma-like” cells were found in drainage material from a percutaneous liver catheter. His temperature continued to spike to 105°F despite appropriate antibiotic coverage. His white blood cell count was 19,000, and hematocrit 25%. A contrast-enhanced CT scan of the abdomen demonstrated a large mass extending from the right lobe of the liver. The mass was inhomogeneous and contained a large fluid density component with multiple septal/31/92; ACCEPTED 6114192. Address correspondence to Jonathan G. Reed, MD, De-
partment
RECEIVED
of Radiology,
4401 Garth Road, 139
San Jacinto Methodist Hospital,
Baytown,
TX 77521.
140
Magnetic Resonance Imaging 0 Volume
(A)
11,
Number 1, 1993
(W
Fig. 1. (A) CT scan shows a large hepatic mass containing extensive necrosis. A tumor capsule is not clearly identified. CT scan shows possible invasion of the right kidney by the hepatic mass (arrow).
ing the subhepatic space, were discovered during the laparotomy. A right hepatic lobectomy was performed. Pathological analysis of the specimen revealed an extensively necrotic tumor separated from com-
Fig. 2(A). NSQ = 6,7 sent tumor, bile during
(B)
pressed normal liver tissue by a focally penetrated fibrous capsule (Fig. 3). The tumor was composed of thin-to-plump spindle cells with slightly myxoid, more compact storiform, and hemangiopericytoma-like ar-
7’r weighted spin echo image (TR 312, TE 16, TI = 0, EN = l/l, SN = 11/12, YFOV = 31.0, XFOV = 82.0, mm, Zofs = 8.22, Tipang = 90, Mag = 1.1114, C = 196, W = 423) shows focal dark and light areas which reprenecrosis, and hemorrhage. The gallbladder demonstrates bright signal due to shortening of r, relaxation time of fasting. ‘s2
Primary malignant fibrous histiocytoma 0
J.G. REED ET AL.
141
eas. These features were consistent with malignant fibrous histiocytoma. Despite chemotherapy, the patient developed extensive brain and lung metastases and died 2 mo after surgery. DISCUSSION
Fig. 2(B). Sagittal images (spin echo TR 300, TE 15, TI = 0, EN = l/l, SN = 9/12, YFOV = 82.0, XFOV = 31.0, NSQ = 8, 7 mm, Zofs = 6.36, Tipang = 90.0, Mag = 1 .O, C = 153, W = 25 1) add significantly to the transaxial views in demonstrating noninvolvement of the right kidney. A tissue plane (large arrow) separates tumor from kidney. Tumor encapsulation is also noted @ma11 arrow).
MFH is the most common sarcoma in the soft tissues.3 It originates from undifferentiated mesenchyma1 cells with differentiation into variable portions of fibroblastic and histiocytic cells.4 Immunoperoxidase studies performed on our patient were interpreted as having no evidence of differentiation toward an epithelial, muscle, nerve, or vascular cell type, thus excluding carcinoma, leiomyosarcoma, neurosarcoma, and angiosarcoma. Markers for vimentin, actin, alpha-l, antichymotrypsin, and alpha-1-antitrypsin indicate that sarcomatous, fibrous, myofibroblastic, and histiocytic differentiation were present. Electron microscopy showed features typical of mesenchymal cells of a pleomorphic sarcoma rather than the rare pseudosarcomatous hepatocellular carcinoma.’ Past CT reports of MFH of the liver described a poorly circumscribed, large avascular mass with central necrosis,6-g which is similar to the CT in our patient. The liver arteriogram appearance was also typical of previously reported descriptions of liver MFH.‘O A few corkscrew tumor vessels were identi-
Fig. 2(C). Transaxial image (TR2000, TE150, TI = 0, EN = 2/2, SN = 6/12, YFOV = 31.0, XFOV = 164, NSQ = 4, 12.0 mm, Zofs = 0.20, Mag = 1.114, Tipang = 90, C = 173, W = 369) showing excellent contrast. The blurriness results from the progressive loss of signal with increasing TE.
142
Magnetic Resonance Imaging 0 Volume 11, Number 1, 1993
Fin. 3. Gross specimen.
The brown-tan tumor mass (short arrow) weighing 1,450 g contains areas of fluctuance and hemorrhage (long arrow) and is mostly necrotic.
fied near the diaphragmatic surface. No tumor stain was present. The MRI appearance of liver MFH can be conjectured from the MRI appearance of other liver tumors and from the MRI appearance of MFH in other organs. Some CT criteria can be directly applied to MRI. Demarcated borders are usually a sign of benignancy, whereas irregular borders usually indicate malignancy. Infiltration and invasion of surrounding organs also indicate malignancy. With CT, benign soft-tissue masses have a uniform density, whereas malignant lesions often contain areas of decreased density due to hemorrhage and necrosis.” On MRI, uniformity of signal on T2-weighted images is a reliable indication of benignancy in the liver, but lack of uniformity does not reliably indicate malignancy.” A review of the MRI appearance of MFH in extrahepatic locations showed that 88% of such tumors had intermediate signal intensity (equal to surrounding muscles) on T,weighted images and 92% had high signal intensity (equal to or higher than subcutaneous fat) on T2weighted images. All tumors were heterogenous on T,-weighted images, with irregular areas of extremely high and low signals representing areas of hemorrhage
and necrosis.” The MRI appearance of MFH of the liver in our patient is similar to the MRI description of MFH in extrahepatic locations. Necrotic cancers nearly always show evidence of hemorrhage. It is not possible to distinguish fluid within a necrotic tumor that is caused by liquefaction of tissue due to autolysis, from fluid caused by bacterial putrification, or from fluid caused by edema. As liquefaction necrosis becomes more confluent, the core demonstrates a lengthening of Tl and T2 relaxation times.13 MR is more sensitive than CT to changes in water content. Necrotic tumors behave like other fluidcontaining structures since T, and T2 relaxation times correlate closely with water content and the breakdown of normal tissue architecture. The brighter T2 signals originate from areas with greater water content and methemoglobin. The darker signals are from areas with less water content and hemosiderin. The term mosaic pattern used to describe the hepatocellular carcinoma “tumor within tumor” appearance on the cut surface of a pathological specimen could be applied here because of the complex pattern on MRl.14 In our patient, tumor encapsulation is evident on the MRI scan and is not apparent on the CT scan. The
Primary malignant fibrous histiocytoma 0 J.G.
pseudocapsule is most apparent on TI images. Many slow-growing types of hepatoma are frequently surrounded by a fibrous capsule. Ebara claims that MRI is twice as sensitive as CT at demonstrating a “ring sign” (fibrous capsule), highly diagnostic of hepatocellular carcinoma, and that no other hepatic mass lesions have this structure.‘5 Evidence that our case represents a primary liver tumor rather than metastasis is that repeated CT scans, MRI and surgery failed to reveal any retroperitoneal mass. Also, retroperitoneal MFH typically displaces but does not invade abdominal organs,16 and liver metastases from extrahepatic intraperitoneal MFH do not occur until a late stage. ” By the time liver metastasis occur from an extrahepatic primary source, the primary becomes very large and therefore the primary location would be easy to discover. Fever and leukocytosis are unusual manifestations of extrahepatic MFH. l1 Of the six cases of primary MFH of the liver reported in the literature,6-9v18 the presence of elevated white blood cell count or fever, or both was mentioned in three cases. In a fourth case, although the author did not mention it, there is reason to suspect that fever and/or elevated white blood cell count were present because an intense inflammatory response was described several times in the discussion of the histology. I8 In two other cases,9 whether or not fever and elevated white blood cell count were present was not discussed. It might be true that liver MFH is more likely to present with fever and elevated white blood cell count than in MFH elsewhere in the body because liver MFH is a deep, bulky, extensively necrotic lesion that is generally not discovered until it is advanced.’ It has been postulated that bulky liver tumors are associated with liver superinfection because the liver constantly filters bacteria from the gut and the liver tumor functions as an obstruction to that filtering mechanism. REFERENCES Hricak, H.; Filly, R.A.; Margeilis, A.R.; et al. Work in progress nuclear magnetic resonance imaging of the gallbladder. Radiology 147:481-484; 1983. Demas, B.E.; Hricak, H.; Moseley, M. Gallbladder bile: An experimental study in dogs using MR imaging and proton spectroscopy. Radiology 157:453-455; 1985. Enzinger, F.M.; Weiss, S.W. Soft Tissue Tumors. St. Louis: CV Mosby Co.; 1983:~~. 66-198.
REED ET AL.
143
4. Weiss, S.W.; Enzinger, EM. Malignant fibrous histiocytoma. An analysis of 200 cases. Cancer 41:2250-2266; 1978. Pathology of the Cell 5. Ghadially, EN. Ultrastructural and Matrix, 3rd ed., vol. 2. London: Butterworths; 1988: pp. 1112-1125. 6. Honda, H.; Nakemura, Y.; Kajiwara, T.; et al. Malignant fibrous histiocytoma of the liver. Comp. Med. Zmaging Graph. 12(2):131-134; 1988. 7. Alberti-Flor, J.J.; O’Hara, M.F.; Weaver, F.; Evans, J.; McClure, R.; Dunn, G.D. Malignant fibrous histiocytoma of the liver. Gastroenterology 89:890-893; 1985. 8. Conran, R.M.; Stocker, J.T. Malignant fibrous histiocytoma of the liver-a case report. Am. J. Gastroenterol. 80(10):813-815; 1985. A.; Laur9. Bruneton, J.N.; Drouillard, J.; Rogopoulos, ent, F.; Normand, F.; Balu-Maestro, L.; Monticelli, J. Extraretroperitoneal abdominal malignant fibrous histiocytoma. Gastrointestinal Radiology 13:299-305; 1988. features of 10. Burgener, EA.; Landman, S. Angiographic malignant fibrous histiocytoma. Radiology 121:581-538; 1976. J.P.; Turner, D.A.; Charters, S.G.; 11. Petasnick, Zacharias, C.E. Soft tissue masses of the locomotor system: comparison of MRImaging with C.T. Radiology 160:125-133; 1986. 12. Mahajan, H.; Kim, E.E.; Wallace, S.; Abello, R.; Benjamin, R.; Evans, H.L. Magnetic resonance imaging of malignant fibrous histiocytoma. Magn. Reson. Imaging 7:283-288; 1989. diseases. In: D.D. 13. Sze, G. Infections and inflammatory Stark, W.G. Bradley (Eds). Magnetic Resonance Imaging. St. Louis: CV Mosby Co.; 1988:~~. 318-319. K.; Furui, S.; Minami, M.; 14. Itai, Y.; Ohtomo, Yoshikawa, K.; Yashiro, N. MRImaging of hepatocellular carcinoma. J. Comput. Assist. Tomogr. 10(6):963968; 1986. 15. Ebara, M.; Ohto, M.; Watanabe, Y.; et al. Diagnosis of small hepatocellular carcinoma: Correlation of M.R. imaging and tumor histologic studies. Radiology 159:371377; 1986. 16. Ros, P.R.; Viamonte, M.; Rywlin, A.M. Review, malignant fibrous histiocytoma: mesenchymal tumor of ubiquitous origin. AJR 142:753-759; 1984. D.; Waxman, J.S.; Janelli, 17. Waxman, M.; Falgenburg, D.E. Malignant fibrous histiocytoma of the colon associated with diverticulitis. Dis. Colon Rectum 26:339343; 1983. 18. Fukayama, M.; Kaike, M. Malignant fibrous histiocytoma arising in the liver. Arch Pathol. Lab Med. 110: 203-206; 1986.