18F-FDG PET/CT of Malignant Angiomyolipoma With Tumor Thrombus.

Renal angiomyolipomas are the most common renal mesenchymal tumors. While classic angiomyolipomas are benign, there are a number of other subtypes. Epithelioid variants are potentially malignant and may be indistinguishable from renal cell carcinoma on imaging. We present a 52-year-old woman who underwent left nephrectomy for an aggressive-appearing malignant renal epithelioid angiomyolipoma. At 6 months postoperatively, restaging FDG PET/CT demonstrated a hypermetabolic left adrenal mass extending to the left adrenal vein, left renal vein, inferior vena cava, and right atrium (SUVmax = 12). Multiple hypermetabolic pulmonary metastases were also noted.