Chronic pain in the right lower abdomen
Our initial differential diagnosis included a cecal carcinoma or a carcinoid of the appendix. The patient was operated. The diagnosis was a cystadenoma of the appendix with hyperplasic changes. The hyperplasic changes resulted in the vascularity within the thickened appendix mimicking a tumor. A cystadenoma was formerly called a mucocele of the appendix. A mucocele of the appendix is an infrequent event, representing 0.3%-0.7% of appendiceal pathology and 8% of appendiceal tumors. It is characterized by a located or diffuse distension of the appendix with a mucus-filled lumen. Spilling of the mucous content can cause pseudomyxoma peritonei. The diagnosis is often made by surgical intervention.
In case of an appendiceal mass, one must be aware of the possibility of one of these diagnoses.
In case of a cystadenoma of the appendix, follow-up is recommended, because sometimes they are associated with colorectal neoplasms and recurrence as pseudomyxoma peritonei.
References
Kim SH, Lim HK, Lee WJ, Lim JH, Byun JY. Mucocele of the appendix: ultrasonographic and CT findings. Abdom Imaging. 1998 May-Jun;23(3):292-6.