[Giant renal angiomyolipoma. Presentation of a case]

A case of large sized angiomyolipoma with atypical clinical presentation is reported. The retroperitoneal mass, showed by ultrasonography, was mainly made by fat tissue, as showed by CT and MRI, and it was associated with focal, probably metastatic, liver lesions. The diagnostic hypothesis of retroperitoneal liposarcoma with liver metastases was made. In the same time a colon neoplasm was found and US-guided biopsies of both the liver lesions and the retroperitoneal mass were carried out. The former were found to be metastases from colon cancer while the latter was a renal angiomyolipoma. The reported case underlines that renal angiomyolipoma if large sized and with atypical clinical presentation may be difficult to differentiate from retroperitoneal, even malignant masses. The hystological evaluation by means of needle biopsy or surgical resection becomes therefore mandatory.