Original Article

Utility of computed tomography and ¹⁸F‐fluorodeoxyglucose with positron emission tomography/computed tomography for distinguishing appendiceal mucocele caused by mucinous adenocarcinoma from other pathologies

Aim

Differentiating appendiceal mucocele with mucinous adenocarcinoma from other pathologies before surgery is difficult. The objective of this study was to evaluate the utility of CT and ¹⁸F‐fluorodeoxyglucose (FDG) with positron emission tomography (PET)/CT for differentiating mucinous adenocarcinoma of appendiceal mucocele from other pathologies.

Method

The study included 25 patients who underwent surgery for clinically diagnosed appendiceal mucoceles detected on CT at the University of Tokyo Hospital. Among these patients, 19 underwent FDG‐PET/CT preoperatively. We compared features of the CT imaging findings and maximum standard uptake values (SUV_max) detected by FDG‐PET/CT between mucocele with mucinous adenocarcinoma and other pathologies.

Results

A total of 13 men (52%) and 12 women (48%) were included in this study, with a median age of 65 years (range 34–83). There were six patients (24%) with pathologically confirmed mucinous adenocarcinoma, 15 patients (60%) with appendiceal mucinous neoplasm and four patients (16%) with simple mucocele caused by chronic inflammation. On the CT findings, wall irregularity was the only significant feature for the two groups in this study (83.3% vs 0.0%, P < 0.01). There was a significant difference in the SUV_max levels on PET/CT between the two groups (100.0% vs 20.0%, P < 0.01).

Conclusion

Distinguishing between mucocele with mucinous adenocarcinoma and other pathologies using imaging modalities is challenging. Our results suggest that wall irregularity on CT and elevated SUV_max on PET/CT are useful factors that can be employed for such discrimination.