Imaging description

When a limb or bifurcation of the adrenal gland lies in the horizontal plane, this orientation can result in the artifactual appearance of a mass in the adrenal gland on axial images. This artifact can be appreciated by correlation with coronal or sagittal reformatted images (Figures 37.1–37.3).

Importance

An adrenal pseudotumor due to horizontal lie may mimic a true tumor of the adrenal gland, provoking unnecessary additional investigations and patient anxiety.

Typical clinical scenario

This pseudotumor occurs primarily as an incidental finding on axial CT images that are of sufficient thickness (5 mm or so) to result in partial voluming of the horizontally oriented portion of the adrenal gland, creating an apparent mass. Thinner CT sections are less likely to result in this artifact.

Differential diagnosis

The artifactual nature of such a pseudotumor can be appreciated by correlation with coronal or sagittal reformatted images. In addition such pseudotumors are typically seen only on one axial image, while a true globular mass might be expected to have roughly similar dimensions in all directions, and to therefore be seen on more than one axial slice.