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The differential imaging features of fat-containing tumors in the peritoneal cavity and retroperitoneum: the radiologic-pathologic correlation.

Shin NY, Kim MJ, Chung JJ, Chung YE, Choi JY, Park YN - Korean J Radiol (2010)

Bottom Line: At the same time, lesions that do not require immediate treatment are being incidentally found at an increasing rate with these same imaging techniques.Thus, the questions about the treatment methods have become increasingly important.Classifying lesions in terms of the necessity of performing surgical treatment can provide important information to clinicians, and this is the one of a radiologist's key responsibilities.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, Severance Hospital, Yonsei University School of Medicine, Seoul, Korea.

ABSTRACT
There are a variety of fat-containing lesions that can arise in the intraperitoneal cavity and retroperitoneal space. Some of these fat-containing lesions, such as liposarcoma and retroperitoneal teratoma, have to be resected, although resection can be deferred for others, such as adrenal adenoma, myelolipoma, angiomyolipoma, ovarian teratoma, and lipoma, until the lesions become large or symptomatic. The third group tumors (i.e., mesenteric panniculitis and pseudolipoma of Glisson's capsule) require medical treatment or no treatment at all. Identifying factors such as whether the fat is macroscopic or microscopic within the lesion, the origin of the lesions, and the presence of combined calcification is important for narrowing the differential diagnosis. The development and wide-spread use of modern imaging modalities make identification of these factors easier so narrowing the differential diagnosis is possible. At the same time, lesions that do not require immediate treatment are being incidentally found at an increasing rate with these same imaging techniques. Thus, the questions about the treatment methods have become increasingly important. Classifying lesions in terms of the necessity of performing surgical treatment can provide important information to clinicians, and this is the one of a radiologist's key responsibilities.

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33-year-old woman with periadrenal mature teratoma.A. Transverse contrast-enhanced CT scan shows well encapsulated cystic mass with fat (arrow) and calcification (open arrow). Isodense, feathery appearance (arrowhead) representing hair is noted.B. Macroscopic fat component (arrow) in cystic mass shows high signal intensity on T1-weighted gradient-echo MR image.C. Sagittal T1-weighted gradient MR image shows displaced spleen (arrow) and left kidney (open arrow).D. Photograph of gross pathologic specimen shows yellowish butter-like keratinous material with hair follicles (arrow) and calcified material (open arrow).
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Figure 6: 33-year-old woman with periadrenal mature teratoma.A. Transverse contrast-enhanced CT scan shows well encapsulated cystic mass with fat (arrow) and calcification (open arrow). Isodense, feathery appearance (arrowhead) representing hair is noted.B. Macroscopic fat component (arrow) in cystic mass shows high signal intensity on T1-weighted gradient-echo MR image.C. Sagittal T1-weighted gradient MR image shows displaced spleen (arrow) and left kidney (open arrow).D. Photograph of gross pathologic specimen shows yellowish butter-like keratinous material with hair follicles (arrow) and calcified material (open arrow).

Mentions: Dedifferentiated liposarcoma is most commonly located in the retroperitoneum, and this is defined as a neoplasm with a well-differentiated liposarcoma juxtaposed to pleomorphic sarcoma. On the CT and MR images, dedifferentiated liposarcoma is seen as well-defined non-lipomatous masses juxtaposed with fatty tumor (10). On the T1-weighted MR images, the signals are hypointense relative to the muscle signals, whereas on the T2-weighted MR images, the tumors show heterogeneous hyperintense signals relative to the muscle intensities (Fig. 5). The heterogeneity on T2-weighted images may be a clue for differentiation between the inflammatory subtype of well-differentiated liposarcoma and dedifferentiated liposarcoma (7). The tumor extent should be defined with caution as the fat components of the tumor could easily be mistaken for adjacent normal fat structures, and missed tumor components could be left after surgical resection (Fig. 6). According to Tateishi et al. (10), the presence of calcification or ossification and the first recurrence after a mean of 13 months, as identified by CT and MRI studies, are significant adverse prognostic factors for primary dedifferentiated liposarcoma of the retroperitoneum.


The differential imaging features of fat-containing tumors in the peritoneal cavity and retroperitoneum: the radiologic-pathologic correlation.

Shin NY, Kim MJ, Chung JJ, Chung YE, Choi JY, Park YN - Korean J Radiol (2010)

33-year-old woman with periadrenal mature teratoma.A. Transverse contrast-enhanced CT scan shows well encapsulated cystic mass with fat (arrow) and calcification (open arrow). Isodense, feathery appearance (arrowhead) representing hair is noted.B. Macroscopic fat component (arrow) in cystic mass shows high signal intensity on T1-weighted gradient-echo MR image.C. Sagittal T1-weighted gradient MR image shows displaced spleen (arrow) and left kidney (open arrow).D. Photograph of gross pathologic specimen shows yellowish butter-like keratinous material with hair follicles (arrow) and calcified material (open arrow).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2864861&req=5

Figure 6: 33-year-old woman with periadrenal mature teratoma.A. Transverse contrast-enhanced CT scan shows well encapsulated cystic mass with fat (arrow) and calcification (open arrow). Isodense, feathery appearance (arrowhead) representing hair is noted.B. Macroscopic fat component (arrow) in cystic mass shows high signal intensity on T1-weighted gradient-echo MR image.C. Sagittal T1-weighted gradient MR image shows displaced spleen (arrow) and left kidney (open arrow).D. Photograph of gross pathologic specimen shows yellowish butter-like keratinous material with hair follicles (arrow) and calcified material (open arrow).
Mentions: Dedifferentiated liposarcoma is most commonly located in the retroperitoneum, and this is defined as a neoplasm with a well-differentiated liposarcoma juxtaposed to pleomorphic sarcoma. On the CT and MR images, dedifferentiated liposarcoma is seen as well-defined non-lipomatous masses juxtaposed with fatty tumor (10). On the T1-weighted MR images, the signals are hypointense relative to the muscle signals, whereas on the T2-weighted MR images, the tumors show heterogeneous hyperintense signals relative to the muscle intensities (Fig. 5). The heterogeneity on T2-weighted images may be a clue for differentiation between the inflammatory subtype of well-differentiated liposarcoma and dedifferentiated liposarcoma (7). The tumor extent should be defined with caution as the fat components of the tumor could easily be mistaken for adjacent normal fat structures, and missed tumor components could be left after surgical resection (Fig. 6). According to Tateishi et al. (10), the presence of calcification or ossification and the first recurrence after a mean of 13 months, as identified by CT and MRI studies, are significant adverse prognostic factors for primary dedifferentiated liposarcoma of the retroperitoneum.

Bottom Line: At the same time, lesions that do not require immediate treatment are being incidentally found at an increasing rate with these same imaging techniques.Thus, the questions about the treatment methods have become increasingly important.Classifying lesions in terms of the necessity of performing surgical treatment can provide important information to clinicians, and this is the one of a radiologist's key responsibilities.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology, Severance Hospital, Yonsei University School of Medicine, Seoul, Korea.

ABSTRACT
There are a variety of fat-containing lesions that can arise in the intraperitoneal cavity and retroperitoneal space. Some of these fat-containing lesions, such as liposarcoma and retroperitoneal teratoma, have to be resected, although resection can be deferred for others, such as adrenal adenoma, myelolipoma, angiomyolipoma, ovarian teratoma, and lipoma, until the lesions become large or symptomatic. The third group tumors (i.e., mesenteric panniculitis and pseudolipoma of Glisson's capsule) require medical treatment or no treatment at all. Identifying factors such as whether the fat is macroscopic or microscopic within the lesion, the origin of the lesions, and the presence of combined calcification is important for narrowing the differential diagnosis. The development and wide-spread use of modern imaging modalities make identification of these factors easier so narrowing the differential diagnosis is possible. At the same time, lesions that do not require immediate treatment are being incidentally found at an increasing rate with these same imaging techniques. Thus, the questions about the treatment methods have become increasingly important. Classifying lesions in terms of the necessity of performing surgical treatment can provide important information to clinicians, and this is the one of a radiologist's key responsibilities.

Show MeSH
Related in: MedlinePlus