Nonobstructive right circumcaval ureter associated with double inferior vena cava

Area of Science:

• Radiology
• Medical Imaging
• Anatomical Variations

Background:

• A circumcaval ureter is a rare congenital anomaly where the ureter courses behind the inferior vena cava.
• Double inferior vena cava (IVC) is another uncommon vascular anomaly.
• The simultaneous occurrence of both anomalies is exceptionally rare, particularly in adults.

Observation:

• This case report details the imaging characteristics of a nonobstructive right circumcaval ureter associated with a double IVC in an adult patient.
• Computed tomography (CT) revealed the retrocaval segment of the ureter as a "thin, long line" on noncontrast-enhanced abdominal scans.
• Intravenous pyelography (IVP) demonstrated a unique appearance of the circumcaval ureter.

Findings:

• The "thin, long line" sign on CT may be a valuable indicator for the incidental diagnosis of circumcaval ureter, even without contrast.
• The specific IVP findings in this case led to the proposal of a new classification system for circumcaval ureter.
• Combined imaging features of circumcaval ureter and double IVC were analyzed.

Implications:

• This case expands the understanding of rare genitourinary and vascular anomalies.
• The proposed CT sign could improve the detection rate of circumcaval ureter during routine abdominal imaging.
• A new classification based on IVP findings may refine the reporting and understanding of circumcaval ureter variations.