Indeterminate renal lesion.

simple cysts (Bozniak 1), cysts with few thin septations and nonenhancing hyperdense lesion (Bozniak 2) are essentially ALL benign (>99.9%). Increasing complexity with thick septation, mural nodularity, may require followup or excision (solid enhancing).

Ultrasound may be all that is needed if simple cyst, but often CT or MR good for confirmation. If no contrast can be given (renal insufficiency) then MRI better