CAVA ON LEFT
HIROSHI ITOH, M.D. TOSHIAKI YOSHIOKA,
JUN UEDA, M.D.
KAZUO HARA, M.D.
From the Departments of Urology and Radiology, Sumitomo Hospital, Osaka, Japan
ABSTRACT -A case of unilateral inferior vena cava (WC) on the left side with left renal cell carcinoma and two polar veins is presented. Preoperative computerized tomogram (CT) and angiogram showed IVC on the left side and tumor thrombus in the left renal vein; that information was helpful during radical nephrectomy.
A fifty-two-year-old man was admitted to our clinic with a complaint of fatigue. He had a mass in the left hypochondrium. Laboratory data were within normal limits, except for microscopic hematuria. Intravenous pyelography (IVP) showed a space-occupying lesion in the lower part of the left kidney pressing the collecting system upward. Abdominal CT demonstrated a left renal tumor occupying the lower pole and an IVC on the left side of the aorta (Fig. 1A). Coronal reconstruction of the abdominal CT (Fig. IB) demonstrated that the left IVC crossed the aorta after draining the left renal vein and joined the suprarenal part of a normal right IVC draining the right renal vein. Selective left renal arteriogram showed hypervascular renal tumor in the lower half of the left kidney. Inferior vena cavogram (Fig. 1C) confirmed the findings of the CT, and selective left renal venogram revealed a defect due to the tumor thrombus in the left renal vein. A radical left nephrectomy was performed transperitoneally. The radiographic findings were confirmed, but in addition there were two polar veins from the lower part of the left kidney, draining into the IVC directly (Fig. 1D). The
operation was completed successfully, and convalescence was uneventful. Comment Congenital anomalies of the vena cava are not frequent, and previous reports were mainly based on cadaver dissection. 1 However with the advance of angiography more reports of these morphogenetic variations have appeared in the literature. 2-4 The inferior vena cava is formed through rather complicated embryogenesis that involves development, regression, anastomosis, and replacement of three pairs of venous channels: posterior cardinal, subcardinal, and supracardinal. It is composed of four segments: hepatic segment derived from the right vitelline vein, prerenal segment from the right subcardinal vein, renal segment from the right subsupracardinal anastomosis, and postrenal segment from the right supracardinal vein. In the classification of congenital anomalies of the IVC,5 postrenal segment is divided into four types: Type A corresponds to the retrocaval ureter or circumcaval ureter; Type B corresponds to the normal IVC; Type C corresponds
.FIGURE 1. (A) Abdominal CT demonstrates left renal tumor and W C on left side of aorta. (Bj Coronal reconstruction of abdominal CT clearly depicts left IVC crossing aorta after draining left renal vein. (C) Inferior vena caoogram shows that abdominal IVC transposed to left side crosses the vertebrae to upper right. (D) Intraoperatlce photograph. W C is situated on left side of aorta. Renal vein and one of two polar veins draining into IVC directly and independentEy are held by tapes.
to IVC on the left side; and Type BC corresponds to double IVC. IVC on the left side is explained as a persistence of the left supracardinal vein, and the incidence found in autopsy is 0.2 per cent.6 However radiographic reports of IVC on the left side are few, and furthermore, a case of WC on the left accompanied with left renal tumor has not been reported as yet. Associated anomaly in this case is two polar veins entering the left kidney from IVC directly and independently. Although supernumerary veins do occur, they are found much less frequently than multiple renal arteries. Reis and Esenther” described that independent polar veins occurred in 1.2 per cent of the cadavers and were always from the right kidney, whereas independent polar veins from the left kidney were never found.
5-2-2. Nakanoshima Kita-ku Osaka 5,30, Japan (DR. NAMIKI)
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