Imaging description

Several venous anatomic variants in the retroperitoneum may mimic adenopathy on CT or MRI [1–7], particularly if the veins are unenhanced or incompletely enhanced. Specifically, a duplicated or left-sided inferior vena cava may simulate para-aortic adenopathy (Figures 51.1 and 51.2). A prominent gonadal vein may mimic retroperitoneal adenopathy (Figure 51.3). A dilated left renal ascending lumbar communicant vein connecting the left renal vein to the lumbar or azygos system may mimic left para-aortic adenopathy (Figure 51.4). Finally, thrombosis of one of these retroperitoneal veins may simulate necrotic adenopathy (Figure 51.5) [8–10].

Importance

Misdiagnosis of retroperitoneal adenopathy may result in unnecessary surgery or treatment, particularly in patients with cancer [1–3].

Typical clinical scenario

Congenital anatomic variations of the inferior vena cava are relatively rare; the reported prevalence of a duplicated inferior vena cava is 0.2 to 3% and that of left-sided inferior vena cava is 0.2 to 0.5% [11, 12]. Dilated gonadal veins are common, and in one study dilated ovarian veins were found in 16 (47%) of 34 asymptomatic women [13]. At conventional left renal venography, alumbar communicant vein was seen in 34 of 100 patients [6].

Differential diagnosis

The primary distinction is between venous anatomic variants and true retroperitoneal adenopathy. Venous variants are identified by their tubular nature and continuity with other vessels.