A 57-year-old woman with a creatinine of 0.8 mg/dL and a normal urine analysis, was investigated with technetium-99m renogram and multidetector computerized tomography (MDCT) as a renal donor for her daughter. The glomerular filtration rate (GFR) was 100 mL/min with the left kidney 42 mL/min and right kidney 58 mL/min. MDCT revealed a large lipomatous tumour on the renal cortex of the left lower pole with exophytic extension into the perirenal space measuring 7.3 × 5.2 cm (Figure 1). The arterial phase revealed dual arterial supply to the left kidney with the tumour being supplied by a branch from the lower renal artery (Figure 2a). The presence of fat [−67 Hounsfield unit (HU)] with interposed soft tissue (42 HU), ectatic vessels and an aneurysm that measured 9 mm × 8.9 mm with no direct arteriovenous shunting favoured the diagnosis of angiomyolipoma.
Fig. 1.
MDCT scan revealing a large lipomatous tumour on the lower pole of the left renal cortex measuring 7.3 × 5.2 cm. *—accessory renal artery, **—aneurysm and ***—fat.
Fig. 2.
(a) MDC scan showing the angiomyolipoma on MDCT scan with dual arterial supply to the left kidney with the tumour being supplied by a branch from the lower renal artery. (b) Complete obliteration of the abnormal feeding artery and the aneurysmal lumen post-embolization is shown.
Superselective catheterization of the feeding artery was performed and the neovascular vessels were embolized. Post-embolization MDCT revealed complete obliteration of the abnormal feeding artery and the aneurysmal lumen (Figure 2b). A week later, the GFR was 107 mL/min, left kidney 43 mL/min and right kidney 64 mL/min.
Angiomyolipoma is a benign renal neoplasm with variable amounts of fat, vascular and smooth muscle elements. Attenuation of less than −20 HU on computerized tomography is widely accepted to confirm the presence of fat and this finding confirms the diagnosis of angiomyolipoma [1]. A tumour >4 cm with an aneurysm measuring >5 mm has a high risk of rupture [2].
Acknowledgments
Conflict of interest statement. None declared.
References
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