Teenager with an abdominal mass

Axial CT without contrast of the abdomen shows the right kidney to be normal in size and to contain multiple small low density lesions that when measured demonstrate negative Hounsfield units. The left kidney, which is massively enlarged, also contains multiple small low density lesions as well as one extremely large low density lesion in its anterior aspect.

The diagnosis was angiomyolipoma of the kidneys in a patient with tuberous sclerosis.