The embedded organ sign

Excerpt

Identifying the organ of origin of a retroperitoneal mass is often difficult for the reporting radiologist, as it can involve several structures around it. One may look for the “embedded organ sign” which is a key to diagnosis. If the retroperitoneal mass is arising from an organ, a part of the organ appears to be embedded in the tumor (Fig. 1a, b). On the contrary, if the retroperitoneal mass is merely compressing the organ and not arising from it, it usually deforms the organ into a crescent shape [1, 2]. Embedded organ sign can be readily appreciated on computed tomography and magnetic resonance images. Retroperitoneal mass lesions can often be large and it is important to identify whether the mass is primarily from the supporting tissues of the retroperitoneum or from a retroperitoneal organ [1, 2]. Apart from the embedded organ sign, there are other signs, which are described in literature to assist in the identification of the organ of origin of a retroperitoneal mass, such as “phantom organ sign,” “beak sign,” and “prominent feeding artery sign” [1]. The management and prognosis of a retroperitoneal mass largely depends on the organ of origin, and the embedded organ sign is useful in identifying the same.

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