Figure 7a. Angiomyolipoma with minimal fat in a 53-year-old man. (a) Unenhanced CT scan obtained during a CT-guided fine-needle biopsy shows a 2.5-cm-diameter hyperattenuating (45 HU) renal mass (arrows). (b) Smear from the aspirate (original magnification, x 400; hemacolor stain) shows densely packed spindle cells without significant atypia, a finding that represents a myoid component. No fat or vessels are seen in this field. The morphologic impression of angiomyolipoma was confirmed at immunocytochemical analysis.