Cause of Pseudomyxoma Peritonei
Pseudomyxoma peritonei is most commonly caused by a ruptured appendiceal mucinous neoplasm (mucocele), which accounts for the vast majority of cases. 1
Primary Origin
Appendiceal mucinous neoplasms are the primary source in most cases of pseudomyxoma peritonei, arising from ruptured appendiceal epithelial tumors that disseminate mucinous material throughout the peritoneal cavity 1, 2
The appendix is now recognized as the predominant origin, with mucinous appendiceal adenocarcinoma being the most frequent histologic subtype 3, 4
Appendiceal mucinous neoplasms represent the most common etiology of pseudomyxoma peritonei across multiple international consensus statements 5, 6
Secondary and Less Common Causes
While the appendix dominates as the primary source, other origins exist but are considerably rarer:
Ovarian neoplasms were historically considered a common primary site, but current evidence demonstrates the ovary is only rarely the true source 7
Most ovarian lesions previously classified as "borderline mucinous tumors" causing pseudomyxoma peritonei are actually metastatic from the appendix rather than primary ovarian tumors 7
Other uncommon sources include mucinous neoplasms of the endocervix, fallopian tube, alimentary organs, urachus, urinary bladder, lung, mucinous splenic cysts, and breast 3
Clinical Implications
The distinction between appendiceal and ovarian origin has critical treatment implications:
When a right pelvic mass is identified in women, appendiceal tumors with pseudomyxoma peritonei may mimic ovarian carcinomas on imaging, necessitating careful differential diagnosis 3
The primary treatment for peritoneal disease from appendiceal origin is cytoreductive surgery combined with hyperthermic intraperitoneal chemotherapy (CRS + HIPEC), which has demonstrated 5-year survival rates of 80% and 10-year survival of 55% 1, 2
This treatment approach is strongly recommended over debulking surgery alone, driven by the known chemoresistance of pseudomyxoma peritonei and the survival benefits observed exclusively with radical surgical intervention 2