Figure 1a. Renal hematoma in a 59-year-old man with lung cancer. (a) Unenhanced CT scan shows a 4 x 2.5-cm slightly heterogeneously hyperattenuating (50 HU) exophytic renal mass (arrowhead) and mild perinephric fat stranding (arrow). (b) Contrast material–enhanced CT scan shows no enhancement of the mass. A percutaneous biopsy, performed because the lesion did not fulfill the criteria for diagnosis of a benign hyperattenuating cyst, yielded fibrous tissue with evidence of chronic inflammation and no malignant cells.