(Radiology. 2001;220:471-474.)
© RSNA, 2001
Case 37: Juxtacaval Fat Collection—Mimic of Lipoma in the Subdiaphragmatic Inferior Vena Cava1
Nalini L. Raju, MD and
John H. M. Austin, MD
1 From the Columbia University College of Physicians and Surgeons, New York, NY (N.L.R.); and Department of Radiology, Columbia Presbyterian Center, New York Presbyterian Hospital, New York, NY (J.H.M.A.). Received September 1, 1999; revision requested October 14; revision received January 21, 2000; accepted February 1. Address correspondence to N.L.R., 240 Grandview Ave W, Roseville, MN 55113 (e-mail: nlraju@rocketmail.com).
Index terms: Diagnosis Please • Fat, 80.92 • Lipoma and lipomatosis, 982.312 • Venae cavae, abnormalities, 982.92 • Venae cavae, CT, 982.12911, 982.12912
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HISTORY
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A 63-year-old man presented to the emergency room with left-sided chest pain. He reported no other symptoms and no history of trauma. He gave a history of asthma since childhood, denied having any other major medical illnesses, and reported taking no medications. Blood pressure was 170/60 mm Hg. Physical examination results were otherwise normal. Complete blood cell count and serum glucose and electrolyte levels were within normal limits. Chest computed tomography (CT) was performed to rule out aortic dissection (Fig 1).
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Figure 1a. (a-c) Contiguous transverse CT images obtained with a 5-mm section thickness, without intravenously administered contrast medium, at the level of the base of the heart and the superior aspect of the liver. (d) Transverse CT image shows attenuation values for two regions also shown in b: -117 HU for region 1 and 34 HU for region 2. Arrow (I) indicates inferior vena cava (IVC). * = region of fat attenuation.
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Figure 1b. (a-c) Contiguous transverse CT images obtained with a 5-mm section thickness, without intravenously administered contrast medium, at the level of the base of the heart and the superior aspect of the liver. (d) Transverse CT image shows attenuation values for two regions also shown in b: -117 HU for region 1 and 34 HU for region 2. Arrow (I) indicates inferior vena cava (IVC). * = region of fat attenuation.
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Figure 1c. (a-c) Contiguous transverse CT images obtained with a 5-mm section thickness, without intravenously administered contrast medium, at the level of the base of the heart and the superior aspect of the liver. (d) Transverse CT image shows attenuation values for two regions also shown in b: -117 HU for region 1 and 34 HU for region 2. Arrow (I) indicates inferior vena cava (IVC). * = region of fat attenuation.
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Figure 1d. (a-c) Contiguous transverse CT images obtained with a 5-mm section thickness, without intravenously administered contrast medium, at the level of the base of the heart and the superior aspect of the liver. (d) Transverse CT image shows attenuation values for two regions also shown in b: -117 HU for region 1 and 34 HU for region 2. Arrow (I) indicates inferior vena cava (IVC). * = region of fat attenuation.
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IMAGING FINDINGS
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Nonenhanced CT images at the level of the subdiaphragmatic IVC (Fig 1) demonstrated a round well-defined region of fat attenuation (-117 HU), presumably in the lumen of the IVC. However, images obtained after the intravenous injection of contrast material (Fig 2) revealed a normal IVC lumen; no filling defect was seen. At coronal reconstruction (Fig 3), adipose tissue was evident medial to the IVC.
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Figure 2. Transverse CT scan obtained with a 5-mm section thickness after intravenous injection of contrast medium shows normal attenuation of the lumen of the IVC, at a similar level as that shown in Figure 1b.
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Figure 3. Coronal reconstruction of CT images obtained with intravenous contrast medium in the plane of a normal-appearing subdiaphragmatic IVC (I) shows a band of adipose tissue (*) at the medial aspect of the IVC.
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DISCUSSION
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Extraluminal adipose tissue that mimics a fatty intraluminal IVC mass is the most common cause of what appears to be an intraluminal mass of fat attenuation in the subdiaphragmatic IVC (1–4). In the present case, a fatty intracaval neoplasm was excluded by using images obtained after intravenous injection of contrast medium that showed an entirely normal lumen of the IVC. Juxtacaval adipose tissue mimicking an intracaval fatty mass has been described as occurring as commonly as in 0.5% of adults undergoing abdominal CT (1).
A characteristic location and appearance of this normal variant has been described (1–4). When present, this localized fat collection is typically observed medially in the lumen of the IVC at or superior to the confluence of the hepatic veins and the IVC. This fat collection is also contiguous with fat around the subdiaphragmatic esophagus. Morphologically, the variant appears in transverse sections as oval or round, is usually oriented obliquely, and is usually no more than 23 mm in diameter (1–4). However, an ultrasonographic (US) example 32 mm in diameter has been described (5). CT attenuation values are in the usual range as those for adipose tissue (1–4).
Miyake et al (1) suggested that the variable appearance of an extracaval fat collection at serial CT results from differences in respiratory depth or pressure (ie, varying degrees of the Valsalva maneuver during suspended respiration). We believe this explains the mechanism by which the filling defect (ie, fat collection) initially observed (Fig 1) was not apparent after administration of contrast medium (Figs 2, 3). It is highly unlikely that the contrast medium per se resulted in the observed phenomenon. Rather, variation in the patient’s inspiratory effort probably resulted in a more accurate image of the IVC. Inspiratory depth was slightly greater in the images obtained after injection of contrast medium than in the images obtained before injection of contrast medium.
However, the possibility that the fatty attenuation may truly be an intracaval lipoma has been raised by Perry et al (2), who reviewed CT and US findings in seven patients with focal fat collections adjacent to the intrahepatic portion of the IVC. Although the authors concluded that each of these collections was probably extraluminal, they pointed out that in several cases, the masses appeared to be within the IVC according to standard radiologic criteria—that is, (a) a contrast material–enhanced ring defining the outer edge of the collection and (b) an acute angle formed by the edge of the collection and the wall of the IVC (2). Since neither surgical exploration nor postmortem studies were performed to define further the location and composition of these lesions, the authors did not establish a definitive anatomic diagnosis. Rather, they thought these cases represented one or both of two phenomena: an extracaval normal variant or an intracaval lipoma.
Han et al (3) used helical CT and two-dimensional reformatted images to study the mechanism by which these extracaval lesions appear intracaval. They proposed that this appearance results from the association of juxtacaval fat with angulation and narrowing of the medial aspect of the immediately subdiaphragmatic IVC (3). In their series, each of the six patients had hepatic disease. Han et al (3) proposed that a shrunken right hepatic lobe may tilt the subdiaphragmatic IVC to the right and create a space at this level that becomes filled by juxtacaval adipose tissue medial to the IVC. However, this association with hepatic disease has not been a consistent finding. Whereas Miyake et al (1) reported hepatic disease in five of 11 patients, Perry et al (2) reported none. In the patient described herein, there was no evidence of hepatic disease, and the subdiaphragmatic IVC was not angled (Fig 3).
The major differential neoplasm of fat attenuation in the IVC is intracaval spread of renal angiomyolipoma (6,7). US depiction of renal angiomyolipoma extending into the IVC in a 16-year-old girl has been described (6). CT depiction of tumor thrombus in the IVC has been reported in association with intracaval extension of a renal angiomyolipoma in a 22-year-old woman with tuberous sclerosis (7). The attenuation value of this tumor thrombus at CT was -48 HU. Enhancement (20 HU) after intravenous injection of contrast medium in that patient can be explained by means of a vascular component. To our knowledge, no proved case of intracaval lipoma, liposarcoma, or other fatty tumors has been reported.
Secondary subdiaphragmatic intracaval neoplasms of soft-tissue, but not fatty, attenuation include renal cell carcinoma, adrenal carcinoma, leiomyoma, and secondary leiomyosarcoma (8,9). Thrombosis in the IVC may or may not be associated with intracaval neoplasm (7,8,10). Moreover, when intravenous contrast material is infused rapidly through an arm vein, laminar flow of increased attenuation from the renal veins may mimic the appearance of a thrombus in the IVC (11).
A nonneoplastic differential consideration is a traumatic tear of the IVC. To our knowledge, one surgically confirmed case of intracaval fat attenuation resulting from herniation of perifalciform fat through a traumatic tear in the intrahepatic IVC has been reported (12). A fat-fluid level has also been described in the IVC as a manifestation of massive fat embolism in a patient who sustained multiple fractures (13). Knowledge of juxtacaval fat collection is important to prevent misdiagnosis and unnecessary diagnostic procedures.
Our congratulations to the 103 individuals who submitted the most likely diagnosis (juxtacaval fat collection – mimic of lipoma in the subdiaphragmatic inferior vena cava) for Diagnosis Please, Case 37. The names and locations of the individuals, as submitted, are as follows:
- Nabil Ammouri, MD, Zahle, Lebanon
- Roger Antonelli, MD, Dayton, Ohio
- Etsuo Aoki, Shimada, Shizuoka, Japan
- Lionel Arrivé, Paris, France
- Yasutaka Baba, Kagoshima, Japan
- Dean Baird, MD, Arlington, Va
- Edward L. Baker, MD, San Francisco, Calif
- Ken Baliga, Rockford, Ill
- Sylvie Beot, MD, Vandoeuvre les Nancy, France
- Giuseppe Brancatelli, MD, Palermo, Italy
- Eric Brecher, MD, Philadelphia, Pa
- Eric L. Bressler, MD, Minnetonka, Minn
- Doug Brown, MD, Durham, NC
- Michael P. Buetow, MD, Okemos, Mich
- Dr. Tirso Cascajares Murillo, Mexico
- Nelson M. G. Caserta, MD, Campinas, SP, Brazil
- Alexander Chako, Virginia Beach, Va
- Chris Chernesky, MD, Springfield, Mo
- Neal R. Conti, MD, Newcastle, Wash
- M. G. de Baets, MD, Lugano, Switzerland
- Manoel de Souza Rocha, MD, São Paulo, SP, Brazil
- William T. Deeter III, MD, Greenville, SC
- Kemal Demir, MD, Ataköy, Istanbul, Turkey
- Giovanna Demurtas, MD, Cagliari, Italy
- Dra. Estela Di Nella, Mar del Plata, Argentina
- Keith D. Epperson, MD, Milwaukee, Wis
- Rainer Erlemann, MD, Duisburg, Germany
- Dr. Luis Fajre, Tucumán, Argentina
- Gabriel C. Fernandez Perez, Vigo, Spain
- Francis Flaherty, MD, Ridgefield, Conn
- Milton R. Fuentealba, MD, General Roca, Rio Negro, Argentina
- Akira Fujikawa, Tokyo, Japan
- Mitsuhiro Furusawa, MD, Fukuoka, Japan
- Michael J. Garcia, MD, Prospect Heights, Ill
- Lori Goffner, MD, Mineola, NY
- Richard S. Goldenson, MD, Brockton, Mass
- Manish Goyal, Saskatoon, Saskatchewan, Canada
- Neil B. Green, MD, Fredericksburg, Va
- Flavius Guglielmo, MD, Basking Ridge, NJ
- Yukihiro Hama, MD, Tokorozawa, Japan
- Rufus W. Head, MD, North Bridgton, Me
- Jer-Shyung Huang, MD, Kaohsiung, Taiwan
- Kenji Kachi, MD, Tokyo, Japan
- Hirotsugu Kado, Fukui, Japan
- Shinichi Kan, Sagamihara, Kanagawa, Japan
- Masako Kataoka, Sakyo, Kyoto, Japan
- Douglas S. Katz, MD, Mineola, NY
- Mitchell A.Klein, MD, Milwaukee, Wis
- Steven A. Klein, MD, Worcester, Mass
- Arlene Klink, MD, Irvine, Calif
- Glenn Krinsky, New York, NY
- Dr. K. Gopi Krishna, Manipal, Karnataka, India
- Dr. Theresa Kuritza, Chicago, Ill
- Stephanos Lachanis, MD, Athens, Greece
- Mario Laguna, West Allis, Wis
- Eduardo Lassalle, MD, Quilmes, Argentina
- Jean Charles Leclerc, MD, Vandoeuvre les Nancy, France
- Myron M. Levitt, East Brunswick, NJ
- Charles Liu, MD, San Diego, Calif
- Yoji Maetani, MD, Sakyo, Kyoto, Japan
- Tatsuya Ya Magen, Fukui, Japan
- Karl E. Magsamen, MD, Chicago, Ill
- Antonio Carlos Maia, Jr, Morumbi, São Paulo, SP, Brazil
- Stephen Manghisi, MD, Closter, NJ
- N. B. S. Mani, MD, Chandigarh, India
- Gildo Matta, MD, Cagliari, Italy
- Michael McDermott, MD, Fredericksburg, Va
- Dr. Luis Mendez Uriburu, Tucumán, Argentina
- Manabu Minami, MD, Tokyo, Japan
- Hidetoshi Miyake, MD, Oita, Japan
- Dr. Eduardo Mondello, Buenos Aires, Argentina
- Carlos F. Munoz-Nunez, Villajoyosa, Spain
- Miguel Eduardo Nazar, MD, Capital Federal, Argentina
- Kuni Ohtomo, MD, Tokyo, Japan
- Dr. Jean-Michel Olicki, Montreuil, France
- David M. Panicek, MD, New York, NY
- Narendrakumar P. Patel, MD, Newburgh, NY
- Suresh K. Patel, Chicago, Ill
- Rachel R. Phillips, MRCP, FRCR, New York, NY
- Alexi J. Phinney, MD, Seattle, Wash
- Rubem Pochaczevsky, MD, Bronx, NY
- Shawn P. Quillin, MD, Charlotte, NC
- David Sacks, MD, West Reading, Pa
- Gabriela Savin, MD, Provincia de Buenos Aires, Argentina
- Stephen D. Scotti, MD, Edina, Minn
- Raymond Selouan, MD, Beirut, Lebanon
- Matt Shapiro, MD, Lowell, Mass
- Yoshihisa Shimanuki, MD, Sendai, Japan
- Taro Shimono, MD, Osaka, Japan
- Paolo Siotto, MD, Cagliari, Italy
- Michael S. Skulski, Carmel, Ind
- Paul Stark, MD, La Jolla, Calif
- David H. Stephens, Rochester, Minn
- Michael Strotzer, MD, Regensburg, Germany
- Carlos Triana, Bogotá, Colombia
- Gustavo A. Triana, Santa Fe de Bogota, Colombia
- Philippe Troufleau, Vandoeuvre les Nancy, France
- Masataka Uetani, MD, Nagasaki, Japan
- Christopher Vittore, MD, Rockford, Ill
- Scott White, Rockford, Ill
- Joe Yut, Olathe, Kan
- Jeffrey H. Zapolsky, MD, Oshkosh, Wis
- Marc Zins, MD, Paris, France
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FOOTNOTES
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Part 1 of this case appeared 4 months previously and may contain larger images.
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REFERENCES
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Perry JN, Williams MP, Dubbins PA, Farrow R. Lipomata of the inferior vena cava: a normal variant?. Clin Radiol 1994; 49:341-342.[CrossRef][Medline]
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Han BK, Im JG, Jung JW, Chung MJ, Yeon KM. Pericaval fat collection that mimics thrombosis of the inferior vena cava: demonstration with use of multi-directional reformation CT. Radiology 1997; 203:105-108.[Abstract/Free Full Text]
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Hines J, Katz DS, Goffner L, Rubin GD. Fat collection related to the intrahepatic inferior vena cava on CT. AJR Am J Roentgenol 1999; 172:409-411.[Abstract/Free Full Text]
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Tobias ME, Berkowitz I. Fat-containing collection adjacent to intrahepatic inferior vena cava: sonographic detection and characterization (letter). AJR Am J Roentgenol 1992; 159:1346.
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Kutcher R, Rosenblass R, Mitsudo S, Goldman M, Kogan S. Renal angiomyolipoma with sonographic demonstration of extension into the inferior vena cava. Radiology 1982; 143:755-756.[Free Full Text]
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Camúñez F, Lafuente J, Robledo R, et al. CT demonstration of extension of renal angiomyolipoma into the inferior vena cava in a patient with tuberous sclerosis. Urol Radiol 1987; 9:152-154.[Medline]
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Marks WM, Korobkin M, Callen PW, Kaiser JA. CT diagnosis of tumor thrombosis of the renal vein and inferior vena cava. AJR Am J Roentgenol 1978; 131:843-846.[Abstract]
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Shida T, Yoshimura M, Chihara H, Nakamura K. Intravenous leiomyomatosis of the pelvis with reextension into the heart. Ann Thorac Surg 1986; 42:104-106.[Abstract]
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Mori H, Maeda H, Fukuda T, et al. Acute thrombosis of the inferior vena cava and hepatic veins in patients with Budd-Chiari syndrome: CT demonstration. AJR Am J Roentgenol 1989; 153:987-991.[Abstract/Free Full Text]
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Vogelzang RL, Gore RM, Neiman HL, Smith SJ, Deschler TW, Vrla RF. Inferior vena cava CT pseudothrombus produced by rapid arm-vein contrast infusion. AJR Am J Roentgenol 1985; 144:843-846.[Abstract/Free Full Text]
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TOP
HISTORY
IMAGING FINDINGS
