ADULT RENAL HAMARTOMAS

Renal angiomyolipomas, the most familiar of the renal hamartomas, are well known to radiologists, despite being uncommon and of limited clin ical importance, because angiomyolipomas represent one of the few lesi ons for which a specific diagnosis can be achieved on the basis of rad iologic findings in the majority of cases, Because of the diversity in the relative amounts of various cellular components and because of th e occasional association with acute hemorrhage, the radiologic feature s of angiomyolipomas can be somewhat varied. At sonography, angiomyoli pomas appear echogenic with acoustic shadowing, At computed tomography (CT), these lesions typically appear as well-marginated, small (<5 cm in size), cortical masses of predominantly fat attenuation with heter ogeneous soft-tissue attenuation interspersed throughout, Some angiomy olipomas are larger and poorly marginated because of hemorrhage, Typic al angiomyolipomas are largely composed of fat; those uncommon tumors without demonstrable fat cannot be radiologically distinguished from r enal cell carcinoma. Renal leiomyoma, a lesion that pathologically ove rlaps with angiomyolipoma to some degree, has a quite different imagin g appearance tie, homogeneous, without detectable fat) that cannot be distinguished from malignant renal lesions.