Introduction: Renal angiomyolipoma (AML) is the most common type of benign mesenchymal tumour of the kidney. It is most often discovered incidentally on imaging, presented as a benign lesion without local invasion. Intravascular invasion to renal vein has been rarely reported in literature.

Case presentation: Here we report a case of renal AML with invasion into the renal vein in a 72 year-old man with hypertension presented with haematuria. Contrast Computed Tomography (CT) revealed a 6cm renal mass lesion with macroscopic fat at upper pole of the right kidney. There was accompanied fatty tumour thrombus invasion into the right renal vein. A positron Emission Tomography- Computed Tomography (PET-CT) scan showed the fatty renal mass was non-FDG avid. Patient had laparoscopic radical nephrectomy with pathology confirmed renal AML with vascular invasion.

Conclusion: Renal AML has the potential to extend into the renal vein, IVC, although it is classified as a benign tumour. Early imaging and therapeutic planning are necessary for the best outcome. Multi-disciplinary collaboration, including radiologist, urologist and the vascular surgeon, is highly recommended for optimal surgical treatment.

Keywords: Kidney; Angiomyolipoma; Renal vein; Thrombosis; Liposarcoma