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Diagnosis Please n
Gail Yarmish, MD Jason DiPoce, MD
History
Case 199
Case 199: Aggressive Angiomyolipoma with Renal Vein Thrombosis and Pulmonary Fat Embolus1 A 70-year-old asymptomatic woman with a history of hypertension visited her primary care physician for a checkup. The findings of a physical examination performed at this time were unremarkable. Laboratory results were remarkable for an increased creatinine level of 1.62 mg/ dL (143.21 mmol/L), which was up from her baseline level of 1.02 mg/dL (90.17 mmol/L). Renal ultrasonography (US) and subsequent computed tomography (CT) of the chest, abdomen, and pelvis were performed.
Imaging Findings Renal US revealed a large echogenic left renal mass (Fig 1). Contrast material–enhanced CT of the abdomen revealed a mixed fat and soft-tissue density mass within the left upper kidney, with fatty tumor thrombus invading the left renal vein (Figs 2, 3). Cysts within the left upper kidney laterally and within the interpolar left kidney were noted incidentally. A cortical defect within the left renal upper pole (Fig 3) and multiple tumor vessels extending into the renal cortex (Figs 2, 3) were also noted. A focus of coarse calcification was noted along the distal aspect of the renal vein thrombus (Fig 3d). There were no other masses or enlarged
lymph nodes. Subsequent CT of the chest revealed emboli composed of macroscopic fat within the right and left lower lobe pulmonary arteries (Fig 4).
Discussion Angiomyolipoma (AML) is the most common benign renal mesenchymal neoplasm arising from the perivascular epithelioid cells and is composed of a variable proportion of dystrophic vessels, smooth muscle, and adipose tissue (1). AML may be either sporadic or seen in association with tuberous sclerosis. The sporadic form accounts for 80%–90% of cases, and it is most common in middle-aged women.
Figure 1
Part one of this case appeared 4 months previously and may contain larger images. Published online 10.1148/radiol.13121187 Content codes: Radiology 2013; 269:615–618 1 From
the Department of Radiology, Staten Island University Hospital, 475 Seaview Ave, Staten Island, NY 10305. Received May 30, 2012; revision requested July 9; revision received July 22; final version accepted August 28. Address correspondence to G.Y. (e-mail: [email protected]). Conflicts of interest are listed at the end of this article. q RSNA, 2013
Figure 1: (a) Transverse and (b) sagittal US images of the left kidney show a large echogenic mass arising from the upper pole of the left kidney.
Radiology: Volume 269: Number 2—November 2013 n radiology.rsna.org
615
DIAGNOSIS PLEASE: Aggressive Angiomyolipoma
Yarmish and DiPoce
Figure 4
Figure 2
Figure 2: (a, b) Contrast-enhanced axial CT images in the corticomedullary phase show a mass with fat attenuation, a renal parenchymal vascular pedicle, and visible tumor vessels extending into the renal parenchyma (arrows). Note the fatty tumor thrombus filling the left renal vein (arrowhead).
Figure 3
Figure 4: Contrast-enhanced (a) axial and (b) coronal CT images of the chest show fatty tumor emboli within the right and left lower lobe pulmonary arteries (arrows).
Figure 3: Contrast-enhanced coronal CT images in the corticomedullary phase show (a) a large left renal mass with fat attenuation and a well-demarcated defect in the renal parenchyma (arrowheads), (c) a parenchymal vascular pedicle (arrow), and (b) fatty tumor thrombus filling the left renal vein. (d) A focus of calcification is noted along the distal left renal vein thrombus.
616
Invasion of the renal vein is a rare but recognized complication of benign AML, and it does not imply malignancy or metastasis (1). In a study of 26 cases of AML with renal vein invasion, the large size of the AML was noted to be a contributing factor, with an average size of 9.5 cm. Central location of the tumor and location on the right side were also noted to be contributing factors. The former is not surprising, as the central location enables tumors to more easily involve the major veins, while frequent occurrence on the right side may relate to the shorter and straighter course of the right renal vein (2). The presence of fatty tumor thrombus within the pulmonary arteries is an even less common feature, with only a few cases reported in the literature (3,4). This case is unique in that the patient was asymptomatic at presentation, with-
radiology.rsna.org n Radiology: Volume 269: Number 2—November 2013
DIAGNOSIS PLEASE: Aggressive Angiomyolipoma
Figure 5
Figure 5: Histopathologic images show (a) a coronal slice through the left renal mass (straight arrow) and (b) the entire left kidney with fatty tumor thrombus extending from the mass into the renal vein. The proximal ureter is included in the gross specimen (curved arrow), and a cyst is noted just lateral to the mass on the coronal image (arrowhead).
out any chest pain or shortness of breath. The patient underwent open radical left nephrectomy with histopathologic confirmation of the diagnosis of AML with ex-
Yarmish and DiPoce
tension to the renal vein and a focal area of infarctlike necrosis with calcification within the renal vein (Fig 5). Despite the rarity and aggressiveness of this presentation, several imaging features indicate a diagnosis of AML. AML is highly vascular, with tumor vessels characteristically extending into or through the renal cortex, a feature that is also known as a renal parenchymal vascular pedicle (5–7). In contrast, perirenal liposarcoma typically manifests as a renal hilar vascular pedicle, with tumor vessels extending from the fatty perirenal mass into renal hilar vessels without traversing the parenchyma. Differing vascular supplies are characteristic of these tumors, as angiomyolipomas arise from the renal parenchyma and therefore share its vascular supply, whereas liposarcomas arise from perinephric fat and therefore have blood supply and drainage separate from those of renal parenchyma (7). The presence of a renal parenchymal defect at the origin of the mass also indicates AML in this patient. Tumors such as angiomyolipoma that arise from the kidney typically have a renal parenchymal defect with a rim of normal renal tissue interfacing with the mass. In contrast, liposarcomas are perinephric tumors that arise from the retroperitoneal fat without a renal parenchymal defect. The latter have a smooth interface with the kidney and compress it as they grow (6). Although the presence of intratumoral calcification has been described as a feature that is highly suggestive of malignancy (7,8), it should be noted that several cases of AML with associated calcification have been noted in the literature (9,10). A variety of causes have been attributed to these cases, including peripheral hemorrhage and osseous metaplasia (9). In this patient, there was no calcification in the intrarenal mass; however, there was a small focus of coarse calcification along the renal vein tumor thrombus. The latter was noted to be associated with a focal area of necrosis at histopathologic evaluation. In summary, there is considerable overlap between the imaging appearance of large exophytic angiomyolipoma and perirenal liposarcoma. The two entities are often confused at imaging and, at
Radiology: Volume 269: Number 2—November 2013 n radiology.rsna.org
times, at histopathologic examination. Close attention to discriminating imaging features will enable confident diagnosis and help guide appropriate medical management and surgical approach. Disclosures of Conflicts of Interest: G.Y. No relevant conflicts of interest to disclose. J.D. No relevant conflicts of interest to disclose.
References 1. Martignoni G, Amin MB. World Health Organization classification of tumours. In: Eble JN, Sauter G, Epstein JI, Sesterhenn IA, eds. Pathology and genetics of tumours of the urinary system and male genital organs. Lyon, France: IARC, 2004; 65–67. 2. Islam AH, Ehara T, Kato H, Hayama M, Kashiwabara T, Nishizawa O. Angiomyolipoma of kidney involving the inferior vena cava. Int J Urol 2004;11(10):897–902. 3. Sandstrom CK, Pugsley J, Mitsumori LM. Renal angiomyolipoma with nontraumatic pulmonary fat embolus. AJR Am J Roentgenol 2009;192(6):W275–W276. 4. Tan YS, Yip KH, Tan PH, Cheng WS. A right renal angiomyolipoma with IVC thrombus and pulmonary embolism. Int Urol Nephrol 2010;42(2):305–308. 5. Wang LJ, Wong YC, Chen CJ, See LC. Computerized tomography characteristics that differentiate angiomyolipomas from liposarcomas in the perinephric space. J Urol 2002;167(2 Pt 1):490–493. 6. Israel GM, Bosniak MA, Slywotzky CM, Rosen RJ. CT differentiation of large exophytic renal angiomyolipomas and perirenal liposarcomas. AJR Am J Roentgenol 2002; 179(3):769–773. 7. Ellingson JJ, Coakley FV, Joe BN, Qayyum A, Westphalen AC, Yeh BM. Computed tomographic distinction of perirenal liposarcoma from exophytic angiomyolipoma: a feature analysis study. J Comput Assist Tomogr 2008;32(4):548–552. 8. Hélénon O, Merran S, Paraf F, et al. Unusual fat-containing tumors of the kidney: a diagnostic dilemma. RadioGraphics 1997; 17(1):129–144. 9. Merran S, Vieillefond A, Peyromaure M, Dupuy C. Renal angiomyolipoma with calcification: CT-pathology correlation. Br J Radiol 2004;77(921):782–783. 10. Hammadeh MY. Calcification within angiomyolipoma. RadioGraphics 1998;18(1):4.
Congratulations to the 148 individuals and 10 resident groups that submitted the most likely diagnosis (aggressive an617
DIAGNOSIS PLEASE: Aggressive Angiomyolipoma
giomyolipoma with renal vein thrombosis and pulmonary fat embolus) for Diagnosis Please, Case 199. The names and locations of the individuals and resident groups, as submitted, are as follows:
Individual responses Osamu Abe, MD, PhD, Itabashi-ku, Tokyo, Japan Jorge Ahualli, MD, San Miguel de Tucuman, Tucuman, Argentina Stephane Aillaud, MD, Aix En Provence, Bouches De Rhones, France Canan Altay, MD, Izmir, Turkey Albert J. Alter, MD, PhD, Blanchardville, Wis Dean E. Baird, MD, Potomac, Md Kenneth F. Baliga, MD, Rockford, Ill Panagiotis Baroutas, MD, Athens, Greece Itsaso Barral Juez, MD, Donostia, Gipuzkoa, Spain Sebastian Bravo-Grau, MD, MSc, Santiago, Region Metropolitana, Chile Eric L. Bressler, MD, Minnetonka, Minn Douglas C. Brown, MD, Virginia Beach, Va Asmitha R. Buddam, MD, Jacksonville, Fla Ian A. Burgess, MD, North Sydney, New South Wales, Australia Daniel Castellon, MD, Fuenlabrada, Madrid, Spain Antonio A. Cavalcanti, MD, Sao Paulo, Brazil Michael H. Childress, MD, Silver Spring, Md Perry Choi, MD, Richmond Hill, Ontario, Canada Sergio A. Criales Vera, MD, Mexico Marco A. Cura, MD, Highland Park, Tex Srinivas Dandamudi, MD, Vijayawada, Andhra Pradesh, India Marc G. De Baets, MD, Collina d'Oro, Ticino, Switzerland Peter de Baets, MD, Damme, Belgium Eduardo P. de Oliveira, Sao Jose do Rio Preto, Brazil Renata de Oliveira e Silva Brenner, MD, Sao Paulo, Brazil Jon J. DeWitte, MD, Bishop, Ga Cooper W. Dean, MD, MS, Gainesville, Fla Mustafa K. Demir, MD, Istanbul, Turkey Thaworn Dendumrongsup, MD, Songkhla, Thailand Dionisios Drakopoulos, MD, Palaio Faliro, Athens, Greece Seyed A. Emamian, MD, PhD, Rockville, Md Christian Escalona-Huerta, MD, Mexico City, Mexico Juliet H. Fallah, MD, Clarendon Hills, Ill Susan M. Fanapour, DO, Lombard, Ill Toshihiro Furuta, MD, Minato-ku, Tokyo, Japan Pedro Garcia, MD, PhD, Gijon, Asturias, Spain Bradley S. Gluck, MD, Southampton, NY Mark G. Goldshein, MD, Andover, Mass Wataru Gonoi, MD, PhD, Bunkyo-ku, Tokyo, Japan Maria A. Gosein, MBBS, FRCR, Santa Cruz, Trinidad And Tobago Ankur Goyal, MBBS, MD, New Delhi, Delhi, India Flavius F. Guglielmo, MD, Moorestown, NJ Ferris M. Hall, MD, Brookline, Mass Srinivasan Harish, MBBS, Burlington, Ontario, Canada Osamu Hasegawa, MD, Koriyama, Fukushima, Japan
618
Yarmish and DiPoce
D. C. Heasley, Jr, MD, Dallas, Tex Christoph Hefel, Feldkirch, Austria Yuusuke Hirokawa, MD, Kyoto, Japan Quoc Bao L. Hoang, MD, Terrytown, La Melanie D. Hoover, MD, Little Rock, Ark Alberto C. Iaia, MD, Wilmington, Del Noriatsu Ichiba, MD, Otsu, Shiga, Japan Takashi Ikeuchi, Moriyama, Shiga, Japan Richard N. Irion, MD, Murray, Utah Devika N. Jajoo, MD, Woodbridge, Conn Anitha James, MBBS, Newcastle under Lyme, Staffordshire, England Sharada Jayagopal, MD, East Williston, NY Kenji Kachi, MD, Tsuchiura, Ibaraki, Japan Kouhei Kamiya, MD, Tokyo, Japan Koki Kato, MD, Utsunomiya, Tochigi, Japan David P. Keating, MD, Jericho, Vt Takao Kiguchi, MD, Niigata, Japan Takuji Kiryu, MD, PhD, Gifu, Japan Mitchell A. Klein, MD, Mequon, Wis Varanasi Krishna, MD, FRCR, Singapore John J. Krol, MD, Lexington, Ky Keshav J. Kulkarni, MBBS, FRCR, Derby, Staffordshire, England Kemmei Kuramoto, MD, Tachikawa, Tokyo, Japan Mario A. Laguna, MD, Milwaukee, Wis Chee Hwee Lee, MD, Taipei, Taiwan David A. Lisle, MBBS, Brisbane, Queensland, Australia Oleg Lysyy, MD, Rishon Lezion, Israel Gerasimos Maroulis, MD, Jonkoping, Sweden Satoshi Matsushima, MD, Tokyo, Japan Albert Mendelson, MD, Northbrook, Ill Mehran Midia, MD, Burlington, Ontario, Canada Manabu Minami, MD, PhD, Yokohama, Japan Kenichi Mizuki, MD, Hamamatsu-shi, Shizuokaken, Japan Jose Mondello, MD, Buenos Aires, Argentina Hiroyuki Morisaka, MD, Kofu, Yamanashi, Japan Kyoko Nagai, MD, Yokohama, Japan Kazuyoshi Nakamura, MD, Yokkaichi, Mie, Japan Tammam N. Nehme, MD, Mattawan, Mich Hironori Nishibori, MD, Minokamo City, Gifu, Japan Tomokazu Nishiguchi, MD, PhD, Osaka, Japan Mizuki Nishino, MD, Boston, Mass Hiroshi Nobusawa, MD, PhD, Ota, Tokyo, Japan Michael D. Orsi, MD, San Antonio, Tex Scott N. Osborne, MD, Memphis, Tenn Vishal Panchal, San Francisco, Calif David M. Panicek, MD, New York, NY Ioannis E. Papachristos, MD, Agrinio, Greece Narendrakumar P. Patel, MD, Newburgh, NY Suresh K. Patel, MD, Chicago, Ill Aruna R. Patil, MD, FRCR, Bangalore, Karnataka, India Yeliz Pekcevik, Izmir, Turkey Emerson A. Pelarigo, Sao Paulo, Brazil Ilias Primetis, MD, Athens, Greece Daniel C. Rappaport, MD, Toronto, Ontario, Canada Ryan P. Rebello, MD, Dundas, Ontario, Canada Hugo Rodriguez Requena, MD, Madrid, Spain Daniel Romeu Vilar, MD, Bertamirans, A Coruna, Spain Stefan Roosendaal, MD, PhD, Amsterdam, the Netherlands Rocky C. Saenz, DO, Farmington Hills, Mich
Akihiko Sakata, MD, Kyoto, Japan Akram Y. Saleh, MD, Baqaiq, Saudi Arabia Meir H. Scheinfeld, MD, Suffern, NY Stephen D. Scotti, MD, Charlottesville, Va Anthony J. Scuderi, MD, Johnstown, Pa Matthew P. Shapiro, MD, Charlottesville, Va Hideki Shima, MD, Narita, Chiba Prefecture, Japan Taro Shimono, MD, Osaka, Japan Ho L. Sie, MD, Henderson, Nev Chrystia M. Slywotzky, MD, New York, NY David F. Sobel, MD, La Jolla, Calif Luis A. Sosa, MD, Milwaukee, Wis James D. Sprinkle, Jr, MD, Spotsylvania, Va Evan G. Stein, MD, PhD, New York, NY Hongliang Sun, MD, Beijing, China Eliko Tanaka, MD, Yokohama, Japan Shota Tatsumoto, Kyoto, Japan Douglas L. Teich, MD, Brookline, Mass Eugene Tong, MD, Austin, Tex Ulysses S. Torres, MD, Bady Bassitt, SP, Brazil Meric Tuzun, MD, Ankara, Turkey Toshiyuki Unno, MD, Tokyo, Japan Pieter E. Vandaele, MD, Brugge, Belgium Piet K. Vanhoenacker, MD, Moorsel, Belgium Publio C. Viana, MD, Sao Paulo, Brazil Ricardo Videla, Cordoba, CB, Argentina Ainhoa Viteri, MD, Bilbao, Biscay, Spain Christopher P. Vittore, MD, Belvidere, Ill Ivan Vollmer, MD, Barcelona, Spain Haruo Watanabe, MD, Gifu, Japan Noritaka Yamakawa, Kyoto, Japan Koji Yamashita, MD, Fukuoka, Japan Fernando I. Yamauchi, MD, Boston, Mass Koichiro Yasaka, MD, Tokyo, Japan Kurata Yasuhisa, MD, Kobe, Hyogo, Japan Hajime Yokota, MD, Chiba, Japan Rika Yoshida, MD, Utsunomiya, Tochigi, Japan Satoru Yoshida, MD, PhD, Muroran, Hokkaido, Japan Kaneko You, Gifu, Japan Stanko Yovichevich, MD, Sydney, New South Wales, Australia Henry R. Zayas, MD, Stuart, Fla Dahua Zhou, MD, Old Westbury, NY Yi Cheng Zhou, MD, Wuhan, Hub, China Ahmed Zidan, MD, Barcelona, Spain
Resident group responses Guangdong General Hospital Resident Group, Quangzhou, Guangdong, China Hospital Universitario de Fuenlabrada Radiology Residents, Madrid, Spain Instituto do Câncer do Estado de São Paulo Residents, Sao Paulo SP, Brazil Mater Dei Hospital Radiology Residents, Malta Mie University Hospital Radiology Residents, MD, Tsu, Mie, Japan Prince of Songkla University Radiology Residents, Songkla, Thailand Tsukuba University Hospital Radiology Residents, Tsukuba, Ibaraki, Japan Universidad Nacional Autonoma de Mexico CT Scanner Residents, Mexico City, Mexico University of Pennsylvania Radiology Residents, Philadelphia, Pa University of Washington Radiology Residents, Seattle, Wash
radiology.rsna.org n Radiology: Volume 269: Number 2—November 2013
Diagnosis Please n
Gail Yarmish, MD Jason DiPoce, MD
History
Case 199
Case 199: Aggressive Angiomyolipoma with Renal Vein Thrombosis and Pulmonary Fat Embolus1 A 70-year-old asymptomatic woman with a history of hypertension visited her primary care physician for a checkup. The findings of a physical examination performed at this time were unremarkable. Laboratory results were remarkable for an increased creatinine level of 1.62 mg/ dL (143.21 mmol/L), which was up from her baseline level of 1.02 mg/dL (90.17 mmol/L). Renal ultrasonography (US) and subsequent computed tomography (CT) of the chest, abdomen, and pelvis were performed.
Imaging Findings Renal US revealed a large echogenic left renal mass (Fig 1). Contrast material–enhanced CT of the abdomen revealed a mixed fat and soft-tissue density mass within the left upper kidney, with fatty tumor thrombus invading the left renal vein (Figs 2, 3). Cysts within the left upper kidney laterally and within the interpolar left kidney were noted incidentally. A cortical defect within the left renal upper pole (Fig 3) and multiple tumor vessels extending into the renal cortex (Figs 2, 3) were also noted. A focus of coarse calcification was noted along the distal aspect of the renal vein thrombus (Fig 3d). There were no other masses or enlarged
lymph nodes. Subsequent CT of the chest revealed emboli composed of macroscopic fat within the right and left lower lobe pulmonary arteries (Fig 4).
Discussion Angiomyolipoma (AML) is the most common benign renal mesenchymal neoplasm arising from the perivascular epithelioid cells and is composed of a variable proportion of dystrophic vessels, smooth muscle, and adipose tissue (1). AML may be either sporadic or seen in association with tuberous sclerosis. The sporadic form accounts for 80%–90% of cases, and it is most common in middle-aged women.
Figure 1
Part one of this case appeared 4 months previously and may contain larger images. Published online 10.1148/radiol.13121187 Content codes: Radiology 2013; 269:615–618 1 From
the Department of Radiology, Staten Island University Hospital, 475 Seaview Ave, Staten Island, NY 10305. Received May 30, 2012; revision requested July 9; revision received July 22; final version accepted August 28. Address correspondence to G.Y. (e-mail: [email protected]). Conflicts of interest are listed at the end of this article. q RSNA, 2013
Figure 1: (a) Transverse and (b) sagittal US images of the left kidney show a large echogenic mass arising from the upper pole of the left kidney.
Radiology: Volume 269: Number 2—November 2013 n radiology.rsna.org
615
DIAGNOSIS PLEASE: Aggressive Angiomyolipoma
Yarmish and DiPoce
Figure 4
Figure 2
Figure 2: (a, b) Contrast-enhanced axial CT images in the corticomedullary phase show a mass with fat attenuation, a renal parenchymal vascular pedicle, and visible tumor vessels extending into the renal parenchyma (arrows). Note the fatty tumor thrombus filling the left renal vein (arrowhead).
Figure 3
Figure 4: Contrast-enhanced (a) axial and (b) coronal CT images of the chest show fatty tumor emboli within the right and left lower lobe pulmonary arteries (arrows).
Figure 3: Contrast-enhanced coronal CT images in the corticomedullary phase show (a) a large left renal mass with fat attenuation and a well-demarcated defect in the renal parenchyma (arrowheads), (c) a parenchymal vascular pedicle (arrow), and (b) fatty tumor thrombus filling the left renal vein. (d) A focus of calcification is noted along the distal left renal vein thrombus.
616
Invasion of the renal vein is a rare but recognized complication of benign AML, and it does not imply malignancy or metastasis (1). In a study of 26 cases of AML with renal vein invasion, the large size of the AML was noted to be a contributing factor, with an average size of 9.5 cm. Central location of the tumor and location on the right side were also noted to be contributing factors. The former is not surprising, as the central location enables tumors to more easily involve the major veins, while frequent occurrence on the right side may relate to the shorter and straighter course of the right renal vein (2). The presence of fatty tumor thrombus within the pulmonary arteries is an even less common feature, with only a few cases reported in the literature (3,4). This case is unique in that the patient was asymptomatic at presentation, with-
radiology.rsna.org n Radiology: Volume 269: Number 2—November 2013
DIAGNOSIS PLEASE: Aggressive Angiomyolipoma
Figure 5
Figure 5: Histopathologic images show (a) a coronal slice through the left renal mass (straight arrow) and (b) the entire left kidney with fatty tumor thrombus extending from the mass into the renal vein. The proximal ureter is included in the gross specimen (curved arrow), and a cyst is noted just lateral to the mass on the coronal image (arrowhead).
out any chest pain or shortness of breath. The patient underwent open radical left nephrectomy with histopathologic confirmation of the diagnosis of AML with ex-
Yarmish and DiPoce
tension to the renal vein and a focal area of infarctlike necrosis with calcification within the renal vein (Fig 5). Despite the rarity and aggressiveness of this presentation, several imaging features indicate a diagnosis of AML. AML is highly vascular, with tumor vessels characteristically extending into or through the renal cortex, a feature that is also known as a renal parenchymal vascular pedicle (5–7). In contrast, perirenal liposarcoma typically manifests as a renal hilar vascular pedicle, with tumor vessels extending from the fatty perirenal mass into renal hilar vessels without traversing the parenchyma. Differing vascular supplies are characteristic of these tumors, as angiomyolipomas arise from the renal parenchyma and therefore share its vascular supply, whereas liposarcomas arise from perinephric fat and therefore have blood supply and drainage separate from those of renal parenchyma (7). The presence of a renal parenchymal defect at the origin of the mass also indicates AML in this patient. Tumors such as angiomyolipoma that arise from the kidney typically have a renal parenchymal defect with a rim of normal renal tissue interfacing with the mass. In contrast, liposarcomas are perinephric tumors that arise from the retroperitoneal fat without a renal parenchymal defect. The latter have a smooth interface with the kidney and compress it as they grow (6). Although the presence of intratumoral calcification has been described as a feature that is highly suggestive of malignancy (7,8), it should be noted that several cases of AML with associated calcification have been noted in the literature (9,10). A variety of causes have been attributed to these cases, including peripheral hemorrhage and osseous metaplasia (9). In this patient, there was no calcification in the intrarenal mass; however, there was a small focus of coarse calcification along the renal vein tumor thrombus. The latter was noted to be associated with a focal area of necrosis at histopathologic evaluation. In summary, there is considerable overlap between the imaging appearance of large exophytic angiomyolipoma and perirenal liposarcoma. The two entities are often confused at imaging and, at
Radiology: Volume 269: Number 2—November 2013 n radiology.rsna.org
times, at histopathologic examination. Close attention to discriminating imaging features will enable confident diagnosis and help guide appropriate medical management and surgical approach. Disclosures of Conflicts of Interest: G.Y. No relevant conflicts of interest to disclose. J.D. No relevant conflicts of interest to disclose.
References 1. Martignoni G, Amin MB. World Health Organization classification of tumours. In: Eble JN, Sauter G, Epstein JI, Sesterhenn IA, eds. Pathology and genetics of tumours of the urinary system and male genital organs. Lyon, France: IARC, 2004; 65–67. 2. Islam AH, Ehara T, Kato H, Hayama M, Kashiwabara T, Nishizawa O. Angiomyolipoma of kidney involving the inferior vena cava. Int J Urol 2004;11(10):897–902. 3. Sandstrom CK, Pugsley J, Mitsumori LM. Renal angiomyolipoma with nontraumatic pulmonary fat embolus. AJR Am J Roentgenol 2009;192(6):W275–W276. 4. Tan YS, Yip KH, Tan PH, Cheng WS. A right renal angiomyolipoma with IVC thrombus and pulmonary embolism. Int Urol Nephrol 2010;42(2):305–308. 5. Wang LJ, Wong YC, Chen CJ, See LC. Computerized tomography characteristics that differentiate angiomyolipomas from liposarcomas in the perinephric space. J Urol 2002;167(2 Pt 1):490–493. 6. Israel GM, Bosniak MA, Slywotzky CM, Rosen RJ. CT differentiation of large exophytic renal angiomyolipomas and perirenal liposarcomas. AJR Am J Roentgenol 2002; 179(3):769–773. 7. Ellingson JJ, Coakley FV, Joe BN, Qayyum A, Westphalen AC, Yeh BM. Computed tomographic distinction of perirenal liposarcoma from exophytic angiomyolipoma: a feature analysis study. J Comput Assist Tomogr 2008;32(4):548–552. 8. Hélénon O, Merran S, Paraf F, et al. Unusual fat-containing tumors of the kidney: a diagnostic dilemma. RadioGraphics 1997; 17(1):129–144. 9. Merran S, Vieillefond A, Peyromaure M, Dupuy C. Renal angiomyolipoma with calcification: CT-pathology correlation. Br J Radiol 2004;77(921):782–783. 10. Hammadeh MY. Calcification within angiomyolipoma. RadioGraphics 1998;18(1):4.
Congratulations to the 148 individuals and 10 resident groups that submitted the most likely diagnosis (aggressive an617
DIAGNOSIS PLEASE: Aggressive Angiomyolipoma
giomyolipoma with renal vein thrombosis and pulmonary fat embolus) for Diagnosis Please, Case 199. The names and locations of the individuals and resident groups, as submitted, are as follows:
Individual responses Osamu Abe, MD, PhD, Itabashi-ku, Tokyo, Japan Jorge Ahualli, MD, San Miguel de Tucuman, Tucuman, Argentina Stephane Aillaud, MD, Aix En Provence, Bouches De Rhones, France Canan Altay, MD, Izmir, Turkey Albert J. Alter, MD, PhD, Blanchardville, Wis Dean E. Baird, MD, Potomac, Md Kenneth F. Baliga, MD, Rockford, Ill Panagiotis Baroutas, MD, Athens, Greece Itsaso Barral Juez, MD, Donostia, Gipuzkoa, Spain Sebastian Bravo-Grau, MD, MSc, Santiago, Region Metropolitana, Chile Eric L. Bressler, MD, Minnetonka, Minn Douglas C. Brown, MD, Virginia Beach, Va Asmitha R. Buddam, MD, Jacksonville, Fla Ian A. Burgess, MD, North Sydney, New South Wales, Australia Daniel Castellon, MD, Fuenlabrada, Madrid, Spain Antonio A. Cavalcanti, MD, Sao Paulo, Brazil Michael H. Childress, MD, Silver Spring, Md Perry Choi, MD, Richmond Hill, Ontario, Canada Sergio A. Criales Vera, MD, Mexico Marco A. Cura, MD, Highland Park, Tex Srinivas Dandamudi, MD, Vijayawada, Andhra Pradesh, India Marc G. De Baets, MD, Collina d'Oro, Ticino, Switzerland Peter de Baets, MD, Damme, Belgium Eduardo P. de Oliveira, Sao Jose do Rio Preto, Brazil Renata de Oliveira e Silva Brenner, MD, Sao Paulo, Brazil Jon J. DeWitte, MD, Bishop, Ga Cooper W. Dean, MD, MS, Gainesville, Fla Mustafa K. Demir, MD, Istanbul, Turkey Thaworn Dendumrongsup, MD, Songkhla, Thailand Dionisios Drakopoulos, MD, Palaio Faliro, Athens, Greece Seyed A. Emamian, MD, PhD, Rockville, Md Christian Escalona-Huerta, MD, Mexico City, Mexico Juliet H. Fallah, MD, Clarendon Hills, Ill Susan M. Fanapour, DO, Lombard, Ill Toshihiro Furuta, MD, Minato-ku, Tokyo, Japan Pedro Garcia, MD, PhD, Gijon, Asturias, Spain Bradley S. Gluck, MD, Southampton, NY Mark G. Goldshein, MD, Andover, Mass Wataru Gonoi, MD, PhD, Bunkyo-ku, Tokyo, Japan Maria A. Gosein, MBBS, FRCR, Santa Cruz, Trinidad And Tobago Ankur Goyal, MBBS, MD, New Delhi, Delhi, India Flavius F. Guglielmo, MD, Moorestown, NJ Ferris M. Hall, MD, Brookline, Mass Srinivasan Harish, MBBS, Burlington, Ontario, Canada Osamu Hasegawa, MD, Koriyama, Fukushima, Japan
618
Yarmish and DiPoce
D. C. Heasley, Jr, MD, Dallas, Tex Christoph Hefel, Feldkirch, Austria Yuusuke Hirokawa, MD, Kyoto, Japan Quoc Bao L. Hoang, MD, Terrytown, La Melanie D. Hoover, MD, Little Rock, Ark Alberto C. Iaia, MD, Wilmington, Del Noriatsu Ichiba, MD, Otsu, Shiga, Japan Takashi Ikeuchi, Moriyama, Shiga, Japan Richard N. Irion, MD, Murray, Utah Devika N. Jajoo, MD, Woodbridge, Conn Anitha James, MBBS, Newcastle under Lyme, Staffordshire, England Sharada Jayagopal, MD, East Williston, NY Kenji Kachi, MD, Tsuchiura, Ibaraki, Japan Kouhei Kamiya, MD, Tokyo, Japan Koki Kato, MD, Utsunomiya, Tochigi, Japan David P. Keating, MD, Jericho, Vt Takao Kiguchi, MD, Niigata, Japan Takuji Kiryu, MD, PhD, Gifu, Japan Mitchell A. Klein, MD, Mequon, Wis Varanasi Krishna, MD, FRCR, Singapore John J. Krol, MD, Lexington, Ky Keshav J. Kulkarni, MBBS, FRCR, Derby, Staffordshire, England Kemmei Kuramoto, MD, Tachikawa, Tokyo, Japan Mario A. Laguna, MD, Milwaukee, Wis Chee Hwee Lee, MD, Taipei, Taiwan David A. Lisle, MBBS, Brisbane, Queensland, Australia Oleg Lysyy, MD, Rishon Lezion, Israel Gerasimos Maroulis, MD, Jonkoping, Sweden Satoshi Matsushima, MD, Tokyo, Japan Albert Mendelson, MD, Northbrook, Ill Mehran Midia, MD, Burlington, Ontario, Canada Manabu Minami, MD, PhD, Yokohama, Japan Kenichi Mizuki, MD, Hamamatsu-shi, Shizuokaken, Japan Jose Mondello, MD, Buenos Aires, Argentina Hiroyuki Morisaka, MD, Kofu, Yamanashi, Japan Kyoko Nagai, MD, Yokohama, Japan Kazuyoshi Nakamura, MD, Yokkaichi, Mie, Japan Tammam N. Nehme, MD, Mattawan, Mich Hironori Nishibori, MD, Minokamo City, Gifu, Japan Tomokazu Nishiguchi, MD, PhD, Osaka, Japan Mizuki Nishino, MD, Boston, Mass Hiroshi Nobusawa, MD, PhD, Ota, Tokyo, Japan Michael D. Orsi, MD, San Antonio, Tex Scott N. Osborne, MD, Memphis, Tenn Vishal Panchal, San Francisco, Calif David M. Panicek, MD, New York, NY Ioannis E. Papachristos, MD, Agrinio, Greece Narendrakumar P. Patel, MD, Newburgh, NY Suresh K. Patel, MD, Chicago, Ill Aruna R. Patil, MD, FRCR, Bangalore, Karnataka, India Yeliz Pekcevik, Izmir, Turkey Emerson A. Pelarigo, Sao Paulo, Brazil Ilias Primetis, MD, Athens, Greece Daniel C. Rappaport, MD, Toronto, Ontario, Canada Ryan P. Rebello, MD, Dundas, Ontario, Canada Hugo Rodriguez Requena, MD, Madrid, Spain Daniel Romeu Vilar, MD, Bertamirans, A Coruna, Spain Stefan Roosendaal, MD, PhD, Amsterdam, the Netherlands Rocky C. Saenz, DO, Farmington Hills, Mich
Akihiko Sakata, MD, Kyoto, Japan Akram Y. Saleh, MD, Baqaiq, Saudi Arabia Meir H. Scheinfeld, MD, Suffern, NY Stephen D. Scotti, MD, Charlottesville, Va Anthony J. Scuderi, MD, Johnstown, Pa Matthew P. Shapiro, MD, Charlottesville, Va Hideki Shima, MD, Narita, Chiba Prefecture, Japan Taro Shimono, MD, Osaka, Japan Ho L. Sie, MD, Henderson, Nev Chrystia M. Slywotzky, MD, New York, NY David F. Sobel, MD, La Jolla, Calif Luis A. Sosa, MD, Milwaukee, Wis James D. Sprinkle, Jr, MD, Spotsylvania, Va Evan G. Stein, MD, PhD, New York, NY Hongliang Sun, MD, Beijing, China Eliko Tanaka, MD, Yokohama, Japan Shota Tatsumoto, Kyoto, Japan Douglas L. Teich, MD, Brookline, Mass Eugene Tong, MD, Austin, Tex Ulysses S. Torres, MD, Bady Bassitt, SP, Brazil Meric Tuzun, MD, Ankara, Turkey Toshiyuki Unno, MD, Tokyo, Japan Pieter E. Vandaele, MD, Brugge, Belgium Piet K. Vanhoenacker, MD, Moorsel, Belgium Publio C. Viana, MD, Sao Paulo, Brazil Ricardo Videla, Cordoba, CB, Argentina Ainhoa Viteri, MD, Bilbao, Biscay, Spain Christopher P. Vittore, MD, Belvidere, Ill Ivan Vollmer, MD, Barcelona, Spain Haruo Watanabe, MD, Gifu, Japan Noritaka Yamakawa, Kyoto, Japan Koji Yamashita, MD, Fukuoka, Japan Fernando I. Yamauchi, MD, Boston, Mass Koichiro Yasaka, MD, Tokyo, Japan Kurata Yasuhisa, MD, Kobe, Hyogo, Japan Hajime Yokota, MD, Chiba, Japan Rika Yoshida, MD, Utsunomiya, Tochigi, Japan Satoru Yoshida, MD, PhD, Muroran, Hokkaido, Japan Kaneko You, Gifu, Japan Stanko Yovichevich, MD, Sydney, New South Wales, Australia Henry R. Zayas, MD, Stuart, Fla Dahua Zhou, MD, Old Westbury, NY Yi Cheng Zhou, MD, Wuhan, Hub, China Ahmed Zidan, MD, Barcelona, Spain
Resident group responses Guangdong General Hospital Resident Group, Quangzhou, Guangdong, China Hospital Universitario de Fuenlabrada Radiology Residents, Madrid, Spain Instituto do Câncer do Estado de São Paulo Residents, Sao Paulo SP, Brazil Mater Dei Hospital Radiology Residents, Malta Mie University Hospital Radiology Residents, MD, Tsu, Mie, Japan Prince of Songkla University Radiology Residents, Songkla, Thailand Tsukuba University Hospital Radiology Residents, Tsukuba, Ibaraki, Japan Universidad Nacional Autonoma de Mexico CT Scanner Residents, Mexico City, Mexico University of Pennsylvania Radiology Residents, Philadelphia, Pa University of Washington Radiology Residents, Seattle, Wash
radiology.rsna.org n Radiology: Volume 269: Number 2—November 2013
