Angiomyolipoma.tuberous sclerosis

Angiomyolipoma.tuberous sclerosis

Clinical History: None given.

Findings: Ultrasound of the right kidney demonstrates a 1.5 cm round hyperechoic structure within the renal parenchyma.

Computed tomography demonstrates a 1.5 cm heterogeneous, but primarily low density right renal lesion with intermixed regions of fat attenuation.

Diagnosis: Angiomyolipoma.

Discussion: An angiomyolipoma is a hamartoma consisting of fat, smooth muscle, and blood vessels, which may on occasion bleed secondary to the vascular elements. Angiomyolipoma are highly associated with tuberous sclerosis (80%). The radiographic features consist of fat attenuation on CT, hyperechoic on ultrasound, and hyperintense on T1 weighted images. The presence of fat in a renal lesion is virtually pathognomonic of angiomyolipoma. Fat within a renal cell CA is extremely rare. It is important to not mistake trapped renal sinus fat within a renal cell CA as angiomyolipoma. Due to the presence of blood vessels, there may be enhancement on post contrast scans. Angiomyolipomas characteristically do not contain calcifications. If calcifications are present, consider another diagnosis.