Teaching Case

Two years after radical nephrectomy for a clear cell renal cell carcinoma of the right kidney, routine CT identified an intraluminal mass in the inferior vena cava.

The patient underwent radical nephrectomy for a 7.5cm mass of the right kidney in November 2000. Histological examination of the nephrectomy specimen revealed a moderately differentiated (G2), clear cell renal cell carcinoma (RCC), extending into the renal vein with no renal capsular or perinephric tissue invasion (pT3b). No pathological lymph nodes were found on surgical exploration.

CT examinations of the abdomen at 6 and 12 months after surgery and abdominal ultrasound at 12 months after surgery were uneventful, with no evidence of recurrence. In July 2002 the patient underwent CT of the abdomen as part of the normal follow-up schedule. Routine CT identified an intraluminal mass floating in the inferior vena cava (IVC). On CT of the total body there was no evidence of distant metastases elsewhere. MRI and spiral CT with contrast medium clearly showed the extent of the thrombus. Therefore, using a thoraco-abdominal approach, cavotomy and thrombectomy by segmental clamping with no caval resection were performed. The pathology of the vena caval tumour revealed a moderately differentiated (G2) clear cell RCC neoplastic thrombus (3cm x 2cm x 1.5cm).

Renal cell carcinoma (RCC) may recur anywhere in the body at any time but a solitary recurrence in the IVC is exceedingly rare. A review of the literature showed only three previously published cases of RCC recurring in the IVC only, with no local recurrence or distant metastases [2-4]. In one of these cases the tumour recurred less than 1 year after nephrectomy [2]. In the other two cases the disease recurred in the IVC after 3 and 5 years, respectively [3,4]. Because of the shorter renal vein and more direct venous drainage, tumours of the right kidney involve the vena cava two to three times more often than do tumours of the left kidney. In two of these three cases reported [2,4] the tumour was in the right kidney, as in the present patient. Regarding the histopathological RCC subtype, in two of these case reports the tumour was a clear cell RCC [3,4], as in the present patient, while the histological subtype was not mentioned in the other case [2].

The most feasible explanation of these late and solitary RCC IVC recurrences is that the thrombus originated from unrecognised involvement of the IVC, and indeed three of these four cases report the solitary recurrence as a consequence of a right RCC.

This is particularly true for the 10 month recurrence [2], but RCC can also recur years after the original diagnosis, through its unpredictable tendency to remain dormant for long periods and also metastasise many years after surgery. Frequently, no clinical signs accompany this type of late and isolated recurrence. A strict follow up is therefore mandatory to achieve an early diagnosis. In our patient the CT scan of the abdomen performed 20 months after radical nephrectomy enabled early diagnosis of a small mass floating in the IVC. The abdominal ultrasound was not performed at that stage while the one performed 12 months after surgery was negative. It is difficult to assess the role of abdominal ultrasound based on this single case. There are indications that ultrasnography is highly accurate in establishing the diagnosis and in determining the extent of tumor thrombus in the IVC. However, non-diagnostic ultrasound examination can occur especially in patients with high body mass index or in case of very small recurrence. In case of radiological suspicion of caval thrombus, contrast-enhanced gadolinium MRI is of great importance in order to determine the thrombus extension and the most useful sequences to be acquired are: SE T1-weighted, GRE T1-weighted, and FSE T2-weighted. We present this rare recurrence to emphasise the importance of a strict surveillance of all patients with RCC and especially for those with pT2, pT3a and pT3b RCC, despite the complete surgical resection of all suspected tumours.