On the annotated coronal image, one can clearly see the appendix (blue) arising from the base of the caecum (green), with the rounded lesion (red) representing the suspected tumour. The retroperitoneal abscess is highlighted in yellow.
On the annotated axial images, one can also appreciate the zone of ulceration (purple) in the suspected appendiceal tip tumour (red) communicating with the retroperitoneal abscess (yellow).