This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Surgery
True pseudomyxoma peritonei is caused by: 
Select and explain. 
A. Cystadenoma of the appendix, B. Mucinous adenocarcinoma, C. Colorectal mucinous cancer, D. Ovarian malignancy
A: Cystadenoma of the appendix
Answer: A: Cystadenoma of the appendix 
Explanation: In reality the pseudomyxoma peritonei or "jelly belly" probably represents mucinous ascites, in association with a cystadenoma of the appendix (resulting in true PMP); to frank mucinous adenocarcinoma. Additionally intestinal mucinous tumours, paicularly colorectal cancers, or any mucinous neoplasm may present with clinical, radiological and pathological features resembling pseudomyxoma peritonei. Ref: World J Gastrointest Oncol 2010 January 15; 2(1): 44-50.