Author(s): Webb EM, Wang ZJ, Westphalen AC, Nakakura EK, Coakley FV,
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Abstract OBJECTIVE: The objective of our study was to evaluate and describe CT features that may differentiate inferior vena cava (IVC) leiomyosarcomas from primary retroperitoneal masses. MATERIALS AND METHODS: A records search revealed 18 CT examinations with a soft-tissue mass contacting the IVC. Three readers evaluated the scans for four signs: an imperceptible IVC at the interface with the mass; a "positive embedded organ" sign (IVC embedded in the periphery of the mass); a "negative embedded organ" sign (IVC compressed at the perimeter of the mass); and tumor in the IVC lumen. CT findings were compared with pathology and operative reports. Performance and significance of CT features and interobserver agreement were calculated. RESULTS: Four of 18 (22\%) retroperitoneal masses were IVC leiomyosarcomas. The IVC was imperceptible at the interface with the mass in three of the four (75\%) IVC leiomyosarcomas (κ = 0.88) and in no alternate diagnosis (p < 0.02). No IVC leiomyosarcoma showed a positive embedded organ sign versus one of 14 masses of alternate origin (p = 1.0, κ = 0.56). The negative embedded organ sign was seen in most primary retroperitoneal masses (11/14 or 79\%, κ = 0.85) but in no case of IVC leiomyosarcoma (p = 0.01). Intraluminal tumor was seen in one of four (25\%) IVC leiomyosarcomas and in two of 14 other retroperitoneal masses (p = 1.0, κ = 1.0). CONCLUSION: An imperceptible IVC at the point of maximal contact with a retroperitoneal mass was the most useful CT feature for predicting the origin of IVC leiomyosarcoma. A negative embedded organ sign was useful for excluding IVC origin. Knowledge of these CT features may assist with preoperative planning.
This article was published in AJR Am J Roentgenol
and referenced in Journal of Cancer Science & Therapy