腔靜脈後輸尿管之案例分享

董世祥¹、  羅華安¹、王彥傑^1、2、王世鋒¹

¹國泰綜合醫院外科部 泌尿科

Retrocaval ureter, a rare congenital anomaly -- case report

 Shih-Shiang Tung¹、 Wah-On Lo¹、Yen-Chieh Wang^1,2、Shih-Feng Wang^1,2

¹Division of Urology, Department of Surgery, Cathay General Hospital, Taipei City, Taiwan

School of Medicine, College of Medicine, Fu-Jen Catholic Unuiversity, New Taipei City, Tainwan

Retrocaval ureter, also known as circumcaval ureter, is a congenital anomaly results from the development of inferior vena cava. Making correct diagnosis can be challenging for a urologist, and delayed diagnosis can lead to deteriorated renal function.

A 29-year-old male with ventricular septal defect and receiving surgical closure in his childhood came to our outpatient department since a right renal cyst was found by the health exam. However, kidney echo showed severe right hydronephrosis and hydroureter. As the patient’s statement, he denied flank pain, abdominal pain or other clinical symptoms and there was no significant finding on physical examination. Blood tests including renal function revealed normal results. Intravenous pyelography showed right mid-ureter kinking obstruction resulted in marked right hydronephrosis and hydroureter. Urological CT scan showed a luminal stenosis and obstructive lesion at the middle ureter, complicated by right severe hydroureter and hydronephrosis.

Right ureteroscopy was performed but neither the guidewire nor the ureteroscope can pass the lesion. Right ureteral catheter was inserted up to 21cm from right ureteral orifice and the patient received retrograde pyelography, which showed severe dilatation of right renal calyces, renal pelvis and upper ureter. Fishhook shape ureter was found and retrocaval ureter or other obstructive etiology was impressed.

The patient received robotic-assisted surgery and the ureter was found crossed behind inferior vena cava. The stricture part was removed and end-to-end ureteroureterostomy was made with 3-0 absorbable suture after a double J stent was indwelled. The post-operative course was uneventful and the double J stent was removed 3 months later. Renal ultrasound and intravenous pyelography 2 months after DBJ removal showed only mild hydronephrosis.

Retrocaval ureter, also referred to as pre-ureteral vena cava, is a rare congenital anomaly results from vascular malformation during embryonal period. There are two types of retrocaval ureter classified by the location where the vena cava cross the ureter. This case report is type 1, in which vena cava cross the ureter at a lower site and leads to a fishhook sign on IVP or pyelography. The disease is usually asymptomatic. Surgical reconstruction of all retrocaval ureter is necessary because ipsilateral renal function can be deteriorated if diagnosis and management were delayed. Fortunately, our patient was diagnosed in early age and the surgical outcome is satisfied.