Appendix cancer for radiologists.
The report that names the mucocele changes the patient’s path.
Imaging is often where appendiceal cancer is first suggested, and the wording of the report decides whether it is acted on. The cystic right-lower-quadrant lesion, low-attenuation mucin, and scalloping of the liver and spleen are the tells that keep it from being read as benign.
The cystic right-lower-quadrant lesion
A well-defined cystic appendiceal mass, sometimes with curvilinear mural calcification and low-attenuation contents, is a mucocele until proven otherwise, and a mucocele can be neoplastic. Name it and recommend surgical referral rather than describing it as a benign cyst. The label you choose is what triggers the next step.
Signs of peritoneal mucin
Scalloping of the hepatic and splenic surfaces, loculated low-density ascites that does not shift with position, and omental caking are classic for pseudomyxoma peritonei. These findings point to mucinous peritoneal disease, usually of appendiceal origin, and deserve to be called out specifically.
An ovarian mass with peritoneal mucin
When a mucinous ovarian mass appears alongside peritoneal mucin, consider an appendiceal primary and suggest evaluating the appendix. Flagging the possibility helps the surgical team avoid treating it as a gynecologic primary.
CT can undercount the disease
CT tends to underestimate peritoneal disease burden compared with what is found at surgery. A scan that looks low-volume is not a reason to withhold cytoreductive surgery. Management follows the 2025 appendiceal consensus guideline, and this guide is a practical orientation, not a substitute for your reporting standards.
Reading a mucocele or peritoneal mucin?
Name it clearly and recommend referral. The report is where the pathway begins.
How to Refer a Patient Standard of Care