Pseudomyxoma peritonei — a heterogenous disease

Abstract

Objective: To evaluate the origin of pseudomyxoma peritonei (PMP) in Chinese women. Methods: The clinicopathologic features of 15 cases of PMP were reviewed. Immunostaining using antibodies for CK7 and CK20 was performed in the ovarian, appendiceal and peritoneal lesions of these cases. Results: Appendiceal pathology was documented in five cases, including four mucinous cystadenoma and one simple mucocele. Eight ovarian tumors were found, including seven mucinous cystadenocarcinomas of low malignant potential and one mucinous cystadenoma. Synchronous ovarian and appendiceal lesions were discovered in three cases. One patient had adenocarcinoma of the pancreas. The origin of mucin production was not known in four cases with metastatic adenocarcinoma found in two of them. Immunoreactivity for CK20 was demonstrated in the tissues derived from the peritoneum, ovary, appendix and pancreas while only 23% (3 out of 13 women) of the peritoneal lesions and 33% (2 out of 6 women) of the ovarian tumors were immunoreactive for CK7. Conclusions: PMP is a heterogeneous lesion, which may develop from mucinous metaplasia of the peritoneum or from appendiceal, or ovarian lesions. Careful examination of the ovary and appendix with performance of appendectomy is advised in every case of PMP. Immunohistochemical examination of the peritoneal, ovarian or appendiceal lesions using antibodies, in particular that for CK7 would help in defining the origin of mucin production.