Computed tomography angiography alone cannot be used to accurately diagnose a disseminated renal tumor that closely resembles a renal artery aneurysm

A 74-year-old woman underwent robot-assisted left partial nephrectomy for left renal cell carcinoma (RCC) at another hospital 5 years ago. However, the tumor recurred, and transarterial embolization (TAE) and radiofrequency ablation were planned. At finding of recurrence tumor, computed tomography angiography (CTA) also showed a left renal artery aneurysm (RAA). However, it was actually a disseminated tumor of RCC fed by the capsular artery, which was diagnosed by catheter-based angiography. Combined segmental artery resection was safely performed under robotic assistance. The pathological diagnosis was a recurrence of RCC. No continuity with the renal artery wall was observed, and vascular invasion was not evident. CTA is very useful in diagnosing RAA. However, CTA alone may lead to misdiagnosis. This paper reveals the pitfalls when diagnosing RAA with CTA. For accurate diagnosis, a combination of CTA and catheter-based angiography should be used.