Classic example of carcinoid tumor, with relatively poor visualization of the primary tumor, which is evidenced by asymmetric nodular thickening of the terminal ileum best seen on the contrast-enhanced CT, with adjacent desmoplastic reaction/spiculation projecting into the mesentery.

What makes this case particularly striking is how subtle the finding is on the non-contrast renal stone CT. It is very easy to overlook on the axial images, but can be seen and should get one's attention when reviewing the coronal reformatted images. This case provides a great example of how multiple projections should be reviewed in every case, in order to increase opportunities to identify subtle but very important abnormalities such as this.