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Dedifferentiated subserosal liposarcoma of the jejunum: sonographic and computed tomographic findings with pathologic correlation
Clinical Imaging 36 (2012) 390 – 393
Dedifferentiated subserosal liposarcoma of the jejunum: sonographic and computed tomographic findings with pathologic correlation Dongjun Jeong a, 1 , Sang Won Kim b,⁎, 1 a
Department of Pathology, Soonchunhyang University Cheonan Hospital, Cheonan, Korea b Department of Radiology, Kyung Hee University Hospital at Gangdong, Seoul, Korea Received 14 June 2011; accepted 19 October 2011
Abstract Dedifferentiated liposarcoma, one of five subtypes of liposarcomas, occurs as a consequence of the progression of well-differentiated liposarcoma to dedifferentiation. Liposarcoma arising from the subserosa of small bowel that can mimic the appearance of mesenteric liposarcoma or teratoma is extremely rare. Here, we report a case of dedifferentiated liposarcoma that developed in the subserosal layer of the jejunum and metastasized to the mesentery. © 2012 Elsevier Inc. All rights reserved. Keywords: Liposarcoma; Small intestine; Ultrasonography; Computed tomography (CT)
1. Introduction Liposarcomas are malignant mesenchymal tumors that tend to develop in the retroperitoneum and the extremities [1,2]. In the peritoneal cavity, liposarcomas can develop in the mesentery and the bowel; however, this is not common. In particular, primary liposarcoma of the small bowel is very rare. There are only a few cases of small bowel liposarcoma reported in the literature [3–5]. A subserosal liposarcoma of the small bowel that can potentially mimic the appearance of a mesenteric lesion is extremely rare. Here, a case of primary liposarcoma of the jejunum is reported, and the sonographic and computed tomographic (CT) findings are correlated with the pathology. 2. Case report A 45-year-old man presented with a large palpable mass in the lower abdomen of 2-month duration. The patient ⁎ Corresponding author. Department of Radiology, Kyung Hee University Hospital at Gangdong, 149 Sangil-Dong, Gangdong-Gu, Seoul, 134-727, Korea. Tel.: +82 2 440 6267; fax: +82 2 440 6932. E-mail address: [email protected] (S.W. Kim). 1 Dongjun Jeong and Sang Won Kim contributed equally to this work. 0899-7071/$ – see front matter © 2012 Elsevier Inc. All rights reserved. doi:10.1016/j.clinimag.2011.10.015
complained of lower abdominal discomfort without tenderness. There was no other significant medical or surgical history. The laboratory data upon admission were within normal range. An abdominal and pelvic sonography using an iU22 unit (Philips Healthcare, Bothell, WA, USA) revealed a 12-cm well-defined mass with mixed internal echogenicity in the lower abdomen; heterogeneous hypoechoic areas were admixed with echogenic portions and septa-like structures (Fig. 1A). The color Doppler showed no definite vascularity in the mass. Subsequently, contrast-enhanced CT of the abdomen and pelvis was performed using an 8-MDCT scanner (LightSpeed Ultra; GE Healthcare, Milwaukee, WI, USA). The CT revealed a large, well-circumscribed, lowattenuated mass with an attenuation of 20–25 HU that measured 12×10 cm in the pelvic cavity (Fig. 1B and C). A few small areas with fat components (−10 to −25 HU) and septa-like structures were observed within the mass. Compared with an unenhanced scan, the majority of components of the mass did not demonstrate contrast enhancement, except for capsule and septa-like structures. The mass abutted the small bowel superiorly. A short segment of the small bowel, in contact with the mass, invaginates slightly toward the mass, forming a small notch
D. Jeong, S.W. Kim / Clinical Imaging 36 (2012) 390–393
391
Fig. 1. A 45-year-old man with a dedifferentiated subserosal liposarcoma that developed in the jejunum. (A) Transabdominal sonogram shows a wellcircumscribed, mixed-echoic soft-tissue mass in the lower abdomen. The mass consists of hypoechoic areas, hyperechoic portions (large arrows), and septalike structures (small arrows). (B) Contrast-enhanced CT coronal reformatted image shows a large soft-tissue mass in the lower abdomen and pelvic cavity (arrows). The short-segmental small bowel (open arrows) invaginates toward the mass, forming surface notch (arrowhead). These findings represent an “embedded organ sign.” Note a low-attenuated fatty component in the mass (small arrow). (C) Contrast-enhanced CT sagittal reformatted image shows a curvilinear enhancing portion in the superior aspect of the mass (arrows), mimicking a capsule (small black arrows). A small portion of fat (small white arrows) and septa-like structures (double arrows) are also present. (D) Contrast-enhanced axial CT scan shows a small nodule that is well enhanced on the mesentery of right abdomen (arrows). (E) Photograph of the cut section shows a well-defined mass with yellowish myxoid areas and grayish white fibrotic areas. Small black arrows indicate dedifferentiated component that was seen as a thick, capsule-like enhancing portion in the mass. A small portion of the mass is attached to the jejunum (large arrows). (F) Photomicrograph [hematoxylin and eosin (H & E) stain, ×40] of the mass shows the tumor mixed with chronic inflammatory cells under the serosa. Arrows indicate the serosal layer. (G) Photomicrograph (H & E stain, ×200) of the mass shows the presence of atypical, hyperchromatic stromal cells and multivacuolated lipoblast (left) and the admixture of atypical spindle cells, large pleomorphic cells with prominent nucleoli, and mixed inflammatory cells (right). This mass consisted of well-differentiated liposarcomatous components (left) and leiomyosarcomatous components (right).
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D. Jeong, S.W. Kim / Clinical Imaging 36 (2012) 390–393
on the superior surface of the mass (Fig. 1B). In addition, a thicker capsule-like enhancing structure was seen in the superior aspect of the mass (Fig. 1B and C). Another 1.8-cm well-enhanced nodule with an attenuation of 130 HU that had been missed during the initial CT interpretation was detected additionally in the right anterior mesentery on retrospective evaluation (Fig. 1D). The diagnosis of a teratoma or liposarcoma of the mesentery was presumed, and surgical removal of the mass was carried out. Grossly, a large bulging mass, 15×10 cm, covered with serosa, was attached to the jejunum (Fig. 1E). Histologically, a large portion of the mass showed adipocyte proliferation (Fig. 1G). Hyperchromatic or bizarre stromal cells and monovacuolated or multivacuolated lipoblasts were also noted. The other portion of the mass was composed of atypical spindle cells, which were positive for smooth muscle actin (SMA), and large pleomorphic cells were noted in the inflammatory background (Fig. 1G). The dedifferentiated component was a leiomyosarcoma; the final diagnosis was a dedifferentiated liposarcoma originating in the subserosal layer of the jejunum. Another small mass found at the mesentery consisted of atypical pleomorphic spindle cells that were reactive to SMA, and inflammatory cells. This small mass was confirmed to be a metastasis from the dedifferentiated component of the liposarcoma. When correlated with the CT findings, a thicker capsule-like structure observed in the superior portion of the mass corresponded to the areas of the dedifferentiated component (Fig. 1B, C, and E).
3. Discussion Histologically, liposarcomas are classified as welldifferentiated, dedifferentiated, myxoid, pleomorphic, and mixed subtypes according to the World Health Organization classification [6]. Dedifferentiated liposarcoma is a neoplasm in which a well-differentiated liposarcoma is juxtaposed with a high-grade nonlipogenic sarcoma; these tumors have an aggressive clinical course with a high rate of local recurrence and distant metastasis [6,7]. The progression of well-differentiated liposarcomas to dedifferentiation occurs if a portion of the tumor histologically differentiates into a nonlipogenic sarcoma [1,6]. The most common component of a nonlipogenic sarcoma, in dedifferentiated liposarcomas, is undifferentiated pleomorphic sarcomas or fibrosarcomas, followed by less frequent patterns such as rhabdomyosarcomas, leiomyosarcomas, or osteosarcomas [6,7]. In this case, a nonlipogenic sarcomatous component was consistent with a leiomyosarcoma that metastasized to the mesentery. Liposarcomas can exhibit a variety of imaging findings ranging from a pure fatty mass to a nonspecific soft-tissue mass without macroscopic fat according to the subtype [1,2]. Dedifferentiated liposarcomas present with varied appearances; the nonlipomatous areas within a fatty mass
and focal fatty areas within a nonlipomatous mass are patterns commonly observed [6,7]. While a large portion of the tumor in the case presented here was a welldifferentiated liposarcoma with abundant myxoid matrix, a smaller proportion of the mass consisted of a leiomyosarcomatous component, which was a curvilinear enhancing portion in the periphery of the mass. The CT appearance of the primary mass was very different from that of a mesenteric metastasis due to the small size of a leiomyomatous component in the main mass. Generally, because imaging findings of dedifferentiated liposarcomas are nonspecific, regardless of the nonlipomatous component types, when a preoperative tissue diagnosis is needed, each component within the tumor should be biopsied in order to arrive at an accurate diagnosis [1]. Tumors of the small bowel are rare, accounting for 1%– 2% of all gastrointestinal tumors [8]. The subserosa is the rarest location within the intestinal layer for the development of submucosal tumors [9]. Although liposarcomas can develop in any region of the body that contains fat, a large fat-containing mass in the peritoneal cavity would not be predicted to be a subserosal liposarcoma of the bowel. When a large soft-tissue mass with fat components presents as in this case, the most likely diagnosis is a teratoma or a liposarcoma that developed in the mesentery. The CT appearance of teratomas consists of fat, water attenuation, and calcification; these findings overlap with those of liposarcomas. However, the majority of gastrointestinal teratomas occur in infants and children [10]. Some teratomas identified in adults occur as a consequence of autoamputation and reimplantation of ovarian teratomas in women [10]. Therefore, clinical information about the patient's age and gender can help differentiate fat-containing soft-tissue masses. Liposarcomas are rare in the mesentery; however, these tumors are one of the most common malignant tumors found in the retroperitoneum [2]. In one imaging study of 10 abdominal liposarcomas, two well-differentiated liposarcomas developed in the mesentery and mesocolon; they had large fatty components on CT and magnetic resonance imaging, with and without components that approximated the characteristics of muscle on imaging, depending on whether they had sclerosing components or not [2]. However, because liposarcomas have a similar appearance, depending on subtype, regardless of its location, determination of the tumor origin may be the only clue for making an accurate diagnosis of large peritoneal tumors. The “embedded organ sign” has been reported to be useful for the determination of tumor origin, especially for large tumors [11]. In cases of large abdominal masses, if a portion of an organ appears to be embedded in the mass, it is likely that the mass arises from this organ. The contact surface between them becomes ulcerative or notched because organs, especially the bowels, are stretched or invaginated toward the mass. On the contrary, the surface of an organ that is in contact with the mass becomes a crescent
D. Jeong, S.W. Kim / Clinical Imaging 36 (2012) 390–393
shape if this is not the organ of origin [11]. In our case, although this was found on retrospective evaluation, the positive embedded organ sign, which is shown as an invagination of adjacent small bowel loop into the mass surface on coronal image, suggests that this soft-tissue mass arises from the small bowel. In conclusion, a dedifferentiated liposarcoma that developed in the subserosal layer of the jejunum presented as a large, fat-containing soft-tissue mass, with a focal peripheral enhancing portion that was confirmed to be a dedifferentiated component of a liposarcoma; the tumor metastasized to the mesentery. In addition, the positive embedded organ sign, observed on the superior surface of the tumor, was the most important clue for identifying the organ of origin. References [1] Craig WD, Fanburg-Smith JC, Henry LR, Guerrero R, Barton JH. Fatcontaining lesions of the retroperitoneum: radiologic-pathologic correlation. Radiographics 2009;29:261–90. [2] Kim T, Murakami T, Oi H, Tsuda K, Matsushita M, Tomoda K, et al. CT and MR imaging of abdominal liposarcoma. AJR Am J Roentgenol 1996;166:829–33.
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[3] De Monti M, Mangoni I, Gobatti D, Ghilardi G, Scorza R. Primary jejunal liposarcoma. Minerva Gastroenterol Dietol 2000;46:119–22. [4] Rivkind AI, Admon D, Yarom R, Schreiber L. Myxoid liposarcoma of the small intestine mimicking acute appendicitis. Eur J Surg 1994;160: 251–2. [5] Mohandas D, Chandra RS, Srinivasan V, Bhaskar AG. Liposarcoma of the ileum with secondaries in the liver. Am J Gastroenterology 1972; 58:172–6. [6] Hong SH, Kim KA, Woo OH, Park CM, Kim CH, Kim MJ, et al. Dedifferentiated liposarcoma of retroperitoneum: spectrum of imaging findings in 15 patients. Clin Imaging 2010;34:203–10. [7] Tateishi U, Hasegawa T, Beppu Y, Satake M, Moriyama N. Primary dedifferentiated liposarcoma of the retroperitoneum. Prognostic significance of computed tomography and magnetic resonance imaging features. J Comput Assist Tomogr 2003;27:799–804. [8] Fang SH, Dong DJ, Chen FH, Jin M, Zhong BS. Small intestinal lipomas: diagnostic value of multi-slice CT enterography. World J Gastroenterol 2010;16:2677–81. [9] Wiech T, Walch A, Werner M. Histopathological classification of nonneoplastic and neoplastic gastrointestinal submucosal lesions. Endoscopy 2005;37:630–4. [10] Ratan SK, Ratan J, Kalra R. Large benign cystic teratoma of the mesosigmoid causing intestinal obstruction: report of a case. Surg Today 2002;32:922–4. [11] Nishino M, Hayakawa K, Minami M, Yamamoto A, Ueda H, Takasu K. Primary retroperitoneal neoplasms: CT and MR imaging findings with anatomic and pathologic diagnostic clues. Radiographics 2003;23:45–57.
Dedifferentiated subserosal liposarcoma of the jejunum: sonographic and computed tomographic findings with pathologic correlation Dongjun Jeong a, 1 , Sang Won Kim b,⁎, 1 a
Department of Pathology, Soonchunhyang University Cheonan Hospital, Cheonan, Korea b Department of Radiology, Kyung Hee University Hospital at Gangdong, Seoul, Korea Received 14 June 2011; accepted 19 October 2011
Abstract Dedifferentiated liposarcoma, one of five subtypes of liposarcomas, occurs as a consequence of the progression of well-differentiated liposarcoma to dedifferentiation. Liposarcoma arising from the subserosa of small bowel that can mimic the appearance of mesenteric liposarcoma or teratoma is extremely rare. Here, we report a case of dedifferentiated liposarcoma that developed in the subserosal layer of the jejunum and metastasized to the mesentery. © 2012 Elsevier Inc. All rights reserved. Keywords: Liposarcoma; Small intestine; Ultrasonography; Computed tomography (CT)
1. Introduction Liposarcomas are malignant mesenchymal tumors that tend to develop in the retroperitoneum and the extremities [1,2]. In the peritoneal cavity, liposarcomas can develop in the mesentery and the bowel; however, this is not common. In particular, primary liposarcoma of the small bowel is very rare. There are only a few cases of small bowel liposarcoma reported in the literature [3–5]. A subserosal liposarcoma of the small bowel that can potentially mimic the appearance of a mesenteric lesion is extremely rare. Here, a case of primary liposarcoma of the jejunum is reported, and the sonographic and computed tomographic (CT) findings are correlated with the pathology. 2. Case report A 45-year-old man presented with a large palpable mass in the lower abdomen of 2-month duration. The patient ⁎ Corresponding author. Department of Radiology, Kyung Hee University Hospital at Gangdong, 149 Sangil-Dong, Gangdong-Gu, Seoul, 134-727, Korea. Tel.: +82 2 440 6267; fax: +82 2 440 6932. E-mail address: [email protected] (S.W. Kim). 1 Dongjun Jeong and Sang Won Kim contributed equally to this work. 0899-7071/$ – see front matter © 2012 Elsevier Inc. All rights reserved. doi:10.1016/j.clinimag.2011.10.015
complained of lower abdominal discomfort without tenderness. There was no other significant medical or surgical history. The laboratory data upon admission were within normal range. An abdominal and pelvic sonography using an iU22 unit (Philips Healthcare, Bothell, WA, USA) revealed a 12-cm well-defined mass with mixed internal echogenicity in the lower abdomen; heterogeneous hypoechoic areas were admixed with echogenic portions and septa-like structures (Fig. 1A). The color Doppler showed no definite vascularity in the mass. Subsequently, contrast-enhanced CT of the abdomen and pelvis was performed using an 8-MDCT scanner (LightSpeed Ultra; GE Healthcare, Milwaukee, WI, USA). The CT revealed a large, well-circumscribed, lowattenuated mass with an attenuation of 20–25 HU that measured 12×10 cm in the pelvic cavity (Fig. 1B and C). A few small areas with fat components (−10 to −25 HU) and septa-like structures were observed within the mass. Compared with an unenhanced scan, the majority of components of the mass did not demonstrate contrast enhancement, except for capsule and septa-like structures. The mass abutted the small bowel superiorly. A short segment of the small bowel, in contact with the mass, invaginates slightly toward the mass, forming a small notch
D. Jeong, S.W. Kim / Clinical Imaging 36 (2012) 390–393
391
Fig. 1. A 45-year-old man with a dedifferentiated subserosal liposarcoma that developed in the jejunum. (A) Transabdominal sonogram shows a wellcircumscribed, mixed-echoic soft-tissue mass in the lower abdomen. The mass consists of hypoechoic areas, hyperechoic portions (large arrows), and septalike structures (small arrows). (B) Contrast-enhanced CT coronal reformatted image shows a large soft-tissue mass in the lower abdomen and pelvic cavity (arrows). The short-segmental small bowel (open arrows) invaginates toward the mass, forming surface notch (arrowhead). These findings represent an “embedded organ sign.” Note a low-attenuated fatty component in the mass (small arrow). (C) Contrast-enhanced CT sagittal reformatted image shows a curvilinear enhancing portion in the superior aspect of the mass (arrows), mimicking a capsule (small black arrows). A small portion of fat (small white arrows) and septa-like structures (double arrows) are also present. (D) Contrast-enhanced axial CT scan shows a small nodule that is well enhanced on the mesentery of right abdomen (arrows). (E) Photograph of the cut section shows a well-defined mass with yellowish myxoid areas and grayish white fibrotic areas. Small black arrows indicate dedifferentiated component that was seen as a thick, capsule-like enhancing portion in the mass. A small portion of the mass is attached to the jejunum (large arrows). (F) Photomicrograph [hematoxylin and eosin (H & E) stain, ×40] of the mass shows the tumor mixed with chronic inflammatory cells under the serosa. Arrows indicate the serosal layer. (G) Photomicrograph (H & E stain, ×200) of the mass shows the presence of atypical, hyperchromatic stromal cells and multivacuolated lipoblast (left) and the admixture of atypical spindle cells, large pleomorphic cells with prominent nucleoli, and mixed inflammatory cells (right). This mass consisted of well-differentiated liposarcomatous components (left) and leiomyosarcomatous components (right).
392
D. Jeong, S.W. Kim / Clinical Imaging 36 (2012) 390–393
on the superior surface of the mass (Fig. 1B). In addition, a thicker capsule-like enhancing structure was seen in the superior aspect of the mass (Fig. 1B and C). Another 1.8-cm well-enhanced nodule with an attenuation of 130 HU that had been missed during the initial CT interpretation was detected additionally in the right anterior mesentery on retrospective evaluation (Fig. 1D). The diagnosis of a teratoma or liposarcoma of the mesentery was presumed, and surgical removal of the mass was carried out. Grossly, a large bulging mass, 15×10 cm, covered with serosa, was attached to the jejunum (Fig. 1E). Histologically, a large portion of the mass showed adipocyte proliferation (Fig. 1G). Hyperchromatic or bizarre stromal cells and monovacuolated or multivacuolated lipoblasts were also noted. The other portion of the mass was composed of atypical spindle cells, which were positive for smooth muscle actin (SMA), and large pleomorphic cells were noted in the inflammatory background (Fig. 1G). The dedifferentiated component was a leiomyosarcoma; the final diagnosis was a dedifferentiated liposarcoma originating in the subserosal layer of the jejunum. Another small mass found at the mesentery consisted of atypical pleomorphic spindle cells that were reactive to SMA, and inflammatory cells. This small mass was confirmed to be a metastasis from the dedifferentiated component of the liposarcoma. When correlated with the CT findings, a thicker capsule-like structure observed in the superior portion of the mass corresponded to the areas of the dedifferentiated component (Fig. 1B, C, and E).
3. Discussion Histologically, liposarcomas are classified as welldifferentiated, dedifferentiated, myxoid, pleomorphic, and mixed subtypes according to the World Health Organization classification [6]. Dedifferentiated liposarcoma is a neoplasm in which a well-differentiated liposarcoma is juxtaposed with a high-grade nonlipogenic sarcoma; these tumors have an aggressive clinical course with a high rate of local recurrence and distant metastasis [6,7]. The progression of well-differentiated liposarcomas to dedifferentiation occurs if a portion of the tumor histologically differentiates into a nonlipogenic sarcoma [1,6]. The most common component of a nonlipogenic sarcoma, in dedifferentiated liposarcomas, is undifferentiated pleomorphic sarcomas or fibrosarcomas, followed by less frequent patterns such as rhabdomyosarcomas, leiomyosarcomas, or osteosarcomas [6,7]. In this case, a nonlipogenic sarcomatous component was consistent with a leiomyosarcoma that metastasized to the mesentery. Liposarcomas can exhibit a variety of imaging findings ranging from a pure fatty mass to a nonspecific soft-tissue mass without macroscopic fat according to the subtype [1,2]. Dedifferentiated liposarcomas present with varied appearances; the nonlipomatous areas within a fatty mass
and focal fatty areas within a nonlipomatous mass are patterns commonly observed [6,7]. While a large portion of the tumor in the case presented here was a welldifferentiated liposarcoma with abundant myxoid matrix, a smaller proportion of the mass consisted of a leiomyosarcomatous component, which was a curvilinear enhancing portion in the periphery of the mass. The CT appearance of the primary mass was very different from that of a mesenteric metastasis due to the small size of a leiomyomatous component in the main mass. Generally, because imaging findings of dedifferentiated liposarcomas are nonspecific, regardless of the nonlipomatous component types, when a preoperative tissue diagnosis is needed, each component within the tumor should be biopsied in order to arrive at an accurate diagnosis [1]. Tumors of the small bowel are rare, accounting for 1%– 2% of all gastrointestinal tumors [8]. The subserosa is the rarest location within the intestinal layer for the development of submucosal tumors [9]. Although liposarcomas can develop in any region of the body that contains fat, a large fat-containing mass in the peritoneal cavity would not be predicted to be a subserosal liposarcoma of the bowel. When a large soft-tissue mass with fat components presents as in this case, the most likely diagnosis is a teratoma or a liposarcoma that developed in the mesentery. The CT appearance of teratomas consists of fat, water attenuation, and calcification; these findings overlap with those of liposarcomas. However, the majority of gastrointestinal teratomas occur in infants and children [10]. Some teratomas identified in adults occur as a consequence of autoamputation and reimplantation of ovarian teratomas in women [10]. Therefore, clinical information about the patient's age and gender can help differentiate fat-containing soft-tissue masses. Liposarcomas are rare in the mesentery; however, these tumors are one of the most common malignant tumors found in the retroperitoneum [2]. In one imaging study of 10 abdominal liposarcomas, two well-differentiated liposarcomas developed in the mesentery and mesocolon; they had large fatty components on CT and magnetic resonance imaging, with and without components that approximated the characteristics of muscle on imaging, depending on whether they had sclerosing components or not [2]. However, because liposarcomas have a similar appearance, depending on subtype, regardless of its location, determination of the tumor origin may be the only clue for making an accurate diagnosis of large peritoneal tumors. The “embedded organ sign” has been reported to be useful for the determination of tumor origin, especially for large tumors [11]. In cases of large abdominal masses, if a portion of an organ appears to be embedded in the mass, it is likely that the mass arises from this organ. The contact surface between them becomes ulcerative or notched because organs, especially the bowels, are stretched or invaginated toward the mass. On the contrary, the surface of an organ that is in contact with the mass becomes a crescent
D. Jeong, S.W. Kim / Clinical Imaging 36 (2012) 390–393
shape if this is not the organ of origin [11]. In our case, although this was found on retrospective evaluation, the positive embedded organ sign, which is shown as an invagination of adjacent small bowel loop into the mass surface on coronal image, suggests that this soft-tissue mass arises from the small bowel. In conclusion, a dedifferentiated liposarcoma that developed in the subserosal layer of the jejunum presented as a large, fat-containing soft-tissue mass, with a focal peripheral enhancing portion that was confirmed to be a dedifferentiated component of a liposarcoma; the tumor metastasized to the mesentery. In addition, the positive embedded organ sign, observed on the superior surface of the tumor, was the most important clue for identifying the organ of origin. References [1] Craig WD, Fanburg-Smith JC, Henry LR, Guerrero R, Barton JH. Fatcontaining lesions of the retroperitoneum: radiologic-pathologic correlation. Radiographics 2009;29:261–90. [2] Kim T, Murakami T, Oi H, Tsuda K, Matsushita M, Tomoda K, et al. CT and MR imaging of abdominal liposarcoma. AJR Am J Roentgenol 1996;166:829–33.
393
[3] De Monti M, Mangoni I, Gobatti D, Ghilardi G, Scorza R. Primary jejunal liposarcoma. Minerva Gastroenterol Dietol 2000;46:119–22. [4] Rivkind AI, Admon D, Yarom R, Schreiber L. Myxoid liposarcoma of the small intestine mimicking acute appendicitis. Eur J Surg 1994;160: 251–2. [5] Mohandas D, Chandra RS, Srinivasan V, Bhaskar AG. Liposarcoma of the ileum with secondaries in the liver. Am J Gastroenterology 1972; 58:172–6. [6] Hong SH, Kim KA, Woo OH, Park CM, Kim CH, Kim MJ, et al. Dedifferentiated liposarcoma of retroperitoneum: spectrum of imaging findings in 15 patients. Clin Imaging 2010;34:203–10. [7] Tateishi U, Hasegawa T, Beppu Y, Satake M, Moriyama N. Primary dedifferentiated liposarcoma of the retroperitoneum. Prognostic significance of computed tomography and magnetic resonance imaging features. J Comput Assist Tomogr 2003;27:799–804. [8] Fang SH, Dong DJ, Chen FH, Jin M, Zhong BS. Small intestinal lipomas: diagnostic value of multi-slice CT enterography. World J Gastroenterol 2010;16:2677–81. [9] Wiech T, Walch A, Werner M. Histopathological classification of nonneoplastic and neoplastic gastrointestinal submucosal lesions. Endoscopy 2005;37:630–4. [10] Ratan SK, Ratan J, Kalra R. Large benign cystic teratoma of the mesosigmoid causing intestinal obstruction: report of a case. Surg Today 2002;32:922–4. [11] Nishino M, Hayakawa K, Minami M, Yamamoto A, Ueda H, Takasu K. Primary retroperitoneal neoplasms: CT and MR imaging findings with anatomic and pathologic diagnostic clues. Radiographics 2003;23:45–57.