To characterize the typical radiologic appearance of ganglioneuromas of the adrenal gland and extra-adrenal retroperitoneum.

The findings of diagnostic imaging studies (CT, n=5; ultrasound, n=1) involving six patients aged 19-58 years with pathologically proven ganglioneuroma were retrospectively analyzed by three radiologist in terms of the lesions' size, shape, margin, location, CT attenuation (unenhanced/contrast-enhanced), necrosis, calcification, relationship with adjacent vessels, and US echogenicity.

The maximum diameter of the six tumors ranged from 10 to 14 (mean, 11.3) cm, and the margin was well-defined in all cases. The homogeneous or slightly heterogeneous attenuation demonstrated at unenhanced CT was less than that of muscle. Dense nodular calcification was present in one case. At contrast-enhanced CT, enhancement was poor (n=5), mild and septum-like, or delayed, heterogeneous and focal (n=3), or involved subtle foci (n=1). In no case was there evidence of necrosis or hemorrhage. Local invasion was absent, but adjacent vascular encasement (n=2) or displacement (n=2) occurred. Ultrasonic examination demonstrated low echogenicity and mild heterogeneity (n=1).

A ganglioneuroma is an uncommon benign neural crest tumor which should be included in the differential diagnosis of a retroperitoneal mass which presents as a well-defined tumor, tend to encase or displace adjacent major blood vessels, and shows low attenuation at unenhanced CT and poor or septum-like focal enhancement at contrast-enhanced CT.