Introduction

Inferior vena cava (IVC) anatomical anomalies are rare, but of high importance in renal surgery. A left-sided IVC is the second most common anomaly of the IVC, and occurs in 0.2%-0.5% of the population.^1-4 The left IVC typically joins the left renal vein, which crosses anterior to the aorta, connecting to the right renal vein to form a normal appearance right-sided IVC. This anomaly is typically found incidentally in imaging studies performed for other reasons. A critical and detailed assessment of these anomalies is important to prevent iatrogenic injuries.

Figure 3. Illustration depicting a left-sided inferior vena cava and large renal mass.

Clinical Case

This is a 58-year-old female patient who presented with a 2-week onset of left-sided abdominal discomfort and early satiety. A CT scan demonstrated a left-sided IVC and a 19 cm renal mass extending from the upper pole of the kidney involving the tail of the pancreas and abutting the stomach (Figures 1-3). The patient also had a 2 cm lesion on the superior aspect of the right lobe of the liver concerning for metastasis. CT of the chest and head revealed no evidence of metastasis in the lung and brain. Her case was presented at tumor board, and given that she was in excruciating pain, the consensus was to proceed to the operating room for a radical nephrectomy. Appropriate counseling and consent were obtained, and the patient was made aware that the resection might involve multiple organs in the surrounding area given the size and appearance of the mass on CT.

An exploratory laparotomy was performed, revealing a large renal mass invading the tail of the pancreas, left adrenal gland, posterior aspect of the stomach, and the diaphragm. There was no tumor thrombus in the renal vein and IVC, and we were able to dissect the IVC off the medial aspect of the mass. A left radical nephrectomy, left adrenalectomy, splenectomy, distal pancreatectomy, and resection of the diaphragm were performed, and the mass was peeled off the posterior aspect of the stomach. Given that the stomach appeared dusky, we performed an indocyanine green angiography with the Quest Spectrum fluorescence camera, which showed no blood flow to the stomach. Hence, we decided to perform a total gastrectomy. The lesion in the liver was also enucleated. Final pathology revealed a liposarcoma of the kidney with local invasion into the tail of the pancreas, spleen, stomach, and diaphragm with negative margins. The liver nodule was a solitary liver metastasis. Her postoperative course was long but uncomplicated. She followed up with medical oncology in the clinic and received chemotherapy. Follow-up imaging at 6 months revealed no evidence of disease.

Discussion

Left-sided IVC is an uncommon anatomical variant that is typically incidentally found on imaging study. IVC anomalies occur during embryogenesis, and take place around the fourth to eighth week of gestation.^3,5 This occurs due to regression of the right supracardinal vein with persistence of the left supracardinal vein.³

There are multiple other variations in the IVC anatomy, including a double IVC, azygos continuation of the IVC, circumaortic left renal vein, retroaortic left renal vein, double IVC with retroaortic right renal vein and hemiazygos continuation of the IVC, double IVC with retroaortic left renal vein and azygos continuation of the IVC, circumcaval ureter, and absence of infrarenal IVC with preservation of the suprarenal segment.⁶

IVC anomalies are very important during retroperitoneal surgery to prevent iatrogenic injuries. Many of these variants may be confused as para-aortic lymphadenopathy or dilated gonadal vein. When in doubt, cross-sectional contrast-enhanced imaging with 3D reconstruction can be useful to better characterize the anatomy during preoperative planning. Left-sided IVC is also important when trying to access the IVC via a transjugular approach for procedures such as IVC filter placement, which could result in placement of the filter in the wrong place.⁷

In conclusion, left-sided IVC is a rare anatomical variant that may have significant surgical implications if undiagnosed prior to surgery. Preoperative identification with cross-sectional imaging is critical to prevent iatrogenic surgical complications.

Conflicts of Interest

The Author has no conflicts of interest to disclose.