Answer for BIR CoW 23 March 2025
IVC leiomyosarcoma
Findings
Relatively well defined large heterogenously enhancing lobulated soft tissue density mass lesion noted involving the intrahepatic and infrahepatic segments of IVC causing expansion and fusiform dilatation with luminal obstruction Hepatic veins and its confluence appears normal The lesion is seen abutting and infiltrating the segment V of right lobe of liver. Central filling defect noted in infrarenal IVC , bilateral common iliac veins reflecting thrombosis - Suggestive of IVC leiomyosarcoma
Discussion
Leiomyosarcoma of the inferior vena cava is a very rare tumor but is the most common primary IVC neoplasm. It is a mesenchymal tumor arising from the smooth muscle fibers of the media, more frequently in the sixth decade of life in women. These tumors exhibit three main growth patterns: extraluminal (62% of cases), intraluminal (5%), and combined extra- and intraluminal (33%) .The tumor is relatively slow growing and tends to expand along the least-resistant tissue planes rather than invade adjacent organs. Leiomyosarcomas are classified into three groups according to their localization in the inferior vena cava. Upper-segment involvement indicates localization from the hepatic vein to the right atrium (24% of cases), middle-segment involvement spans the hepatic to renal veins (42%), and lower-segment involvement includes the infrarenal area (34%). Upper-segment involvement may manifest as Budd-Chiari syndrome, middle-segment involvement may manifest as nephrotic syndrome, and infrarenal involvement may manifest as lower extremity edema. The tumor may extend into the right side of the heart and, rarely, into the pulmonary artery. CT is useful for identifying, diagnosing, and following up of intravascular leiomyosarcomas. The most typical imaging appearance of these tumors includes vein dilatation and an intermediate-attenuation mass with irregular enhancement and total or near-complete vein obstruction. The tumor is lobulated, well-defined, and heterogeneous and exhibits signs of hemorrhage and necrosis. Calcification is unusual .An intraluminal leiomyosarcoma is difficult to detect at CT without the use of contrast material and can be readily depicted at MR imaging .Signal characteristics depend on the degree of necrosis, which appears low intensity on T1-weighted images and high intensity on T2-weighted images .In contrast to bland thrombus, intraluminal leiomyosarcoma tumor thrombus appears iso- to hyperintense on T2-weighted images, enhances on T1-weighted postcontrast images, and expands the lumen . Given the complex appearances of these tumors, both CT and MR imaging are useful for differentiating a neoplasm from a simple thrombus. The three-dimensional capability of MR imaging permits intra- and extraluminal staging and determination of adjacent organ involvement . Other less common retroperitoneal mesenchymal neoplasms that may involve the IVC: Angiosarcoma:MRI Findings reflect the hemorrhagic nature of angiosarcomas with fluid-fluid levels often a feature Liposarcoma: inhomogeneous attenuation, with evidence of significant amounts of soft-tissue within the fatty mass Leiomyomatosis Undifferentiated pleomorphic Sarcoma: These tumors are typically relatively well-circumscribed, located within or adjacent to muscle, exerting a positive mass effect on surrounding structures due to their (usual) large size at presentation
Findings
Relatively well defined large heterogenously enhancing lobulated soft tissue density mass lesion noted involving the intrahepatic and infrahepatic segments of IVC causing expansion and fusiform dilatation with luminal obstruction Hepatic veins and its confluence appears normal The lesion is seen abutting and infiltrating the segment V of right lobe of liver. Central filling defect noted in infrarenal IVC , bilateral common iliac veins reflecting thrombosis - Suggestive of IVC leiomyosarcoma
Discussion
Leiomyosarcoma of the inferior vena cava is a very rare tumor but is the most common primary IVC neoplasm. It is a mesenchymal tumor arising from the smooth muscle fibers of the media, more frequently in the sixth decade of life in women. These tumors exhibit three main growth patterns: extraluminal (62% of cases), intraluminal (5%), and combined extra- and intraluminal (33%) .The tumor is relatively slow growing and tends to expand along the least-resistant tissue planes rather than invade adjacent organs. Leiomyosarcomas are classified into three groups according to their localization in the inferior vena cava. Upper-segment involvement indicates localization from the hepatic vein to the right atrium (24% of cases), middle-segment involvement spans the hepatic to renal veins (42%), and lower-segment involvement includes the infrarenal area (34%). Upper-segment involvement may manifest as Budd-Chiari syndrome, middle-segment involvement may manifest as nephrotic syndrome, and infrarenal involvement may manifest as lower extremity edema. The tumor may extend into the right side of the heart and, rarely, into the pulmonary artery. CT is useful for identifying, diagnosing, and following up of intravascular leiomyosarcomas. The most typical imaging appearance of these tumors includes vein dilatation and an intermediate-attenuation mass with irregular enhancement and total or near-complete vein obstruction. The tumor is lobulated, well-defined, and heterogeneous and exhibits signs of hemorrhage and necrosis. Calcification is unusual .An intraluminal leiomyosarcoma is difficult to detect at CT without the use of contrast material and can be readily depicted at MR imaging .Signal characteristics depend on the degree of necrosis, which appears low intensity on T1-weighted images and high intensity on T2-weighted images .In contrast to bland thrombus, intraluminal leiomyosarcoma tumor thrombus appears iso- to hyperintense on T2-weighted images, enhances on T1-weighted postcontrast images, and expands the lumen . Given the complex appearances of these tumors, both CT and MR imaging are useful for differentiating a neoplasm from a simple thrombus. The three-dimensional capability of MR imaging permits intra- and extraluminal staging and determination of adjacent organ involvement . Other less common retroperitoneal mesenchymal neoplasms that may involve the IVC: Angiosarcoma:MRI Findings reflect the hemorrhagic nature of angiosarcomas with fluid-fluid levels often a feature Liposarcoma: inhomogeneous attenuation, with evidence of significant amounts of soft-tissue within the fatty mass Leiomyomatosis Undifferentiated pleomorphic Sarcoma: These tumors are typically relatively well-circumscribed, located within or adjacent to muscle, exerting a positive mass effect on surrounding structures due to their (usual) large size at presentation
Note:
We do not discourage differential diagnosis. But all the differentials must satisfy the findings noted in the case.
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Did you Know?
The order in which the names appear in this winner's list is based on the time of submission. The first person to send the correct answer gets his/her name on top of the list!
We do not discourage differential diagnosis. But all the differentials must satisfy the findings noted in the case.
If you feel you have answered rightly but cannot find your name in the above list, please call 09551942599.
Did you Know?
The order in which the names appear in this winner's list is based on the time of submission. The first person to send the correct answer gets his/her name on top of the list!