Aim: To investigate whether a grading system of renal AMLs based on digital subtraction angiography (DSA) and computerized tomography (CT), could help to select patients for embolization.
Materials and methods: Thirty patients with 35 renal angiomyolipomas (size range 4-20 cm, mean 9.9 cm) underwent both digital subtraction angiography (DSA) and computed tomography (CT). Based on the DSA appearance the tumours were graded into three grades: grade I, minimal vascularity; grade II, moderate vascularity; grade III, marked vascularity.
Results: There were seven grade I (mean 9.3 cm, range 4.5-20 cm), 18 grade II (mean 8.9 cm, range 5-18 cm) and 10 grade III tumours (mean 12.1 cm, range 4-20 cm). Five grade I tumours did not cause symptoms (71%) and two caused flank pain and haematuria, respectively (14.3% each). Nine of the grade II tumours were asymptomatic (50%), seven caused bleeding (39%) and two caused flank pain (11%). Four grade III tumours were asymptomatic (40%), five caused bleeding (50%) and one pain (10%).
Conclusions: According to our criteria, large angiomyolipomas with minimal vascularity are less likely to bleed, and do not need prophylactic treatment. This needs to be confirmed in larger studies.