MUCINOUS TUMORS OF THE VERMIFORM APPENDIX AND OVARY, AND PSEUDOMYXOMAPERITONEI - HISTOGENETIC IMPLICATIONS OF CYTOKERATIN-7 EXPRESSION

Cytokeratin 7 (CK-7) has been shown to be uncommonly expressed in colo nic epithelial tumors, as opposed to ovarian epithelial tumors, which are always CK-7 positive. The authors investigated the expression of C K-7 in 17 appendiceal cystadenomas and carcinomas, 20 mucinous borderl ine tumors of the ovary, 10 cases of simultaneous mucinous tumors of t he appendix and ovary, three so-called high-stage mucinous borderline tumors of the ovary, and three cases of pseudomyxoma peritonei (PP) of unknown origin. Nine appendiceal cystadenomas were CK-7 negative; two of these were associated with PP, and the peritoneal lesions were neg ative as well. Three cystadenomas were CK-7 positive. Three appendicea l carcinomas were CK-7 negative, and in one case the metastases were a lso negative. Two carcinomas were CK-7 positive. All 20 ovarian border line tumors were CK-7 positive. Six cases of simultaneous mucinous tum ors of the ovary and appendix were CK-7 negative, as were their perito neal mucinous deposits. Four cases showed a positive reaction in both appendiceal and ovarian sites. Two of three so-called high-stage ovari an borderline tumors were CK-7 negative. All three cases of PP of unkn own origin were CK-7 negative. In conclusion, appendiceal cystadenomas are often CK-7 negative, whereas ovarian mucinous borderline tumors a re always CK-7 positive. The concordant staining pattern for CK-7 of s imultaneous mucinous tumors involving the appendix and ovary (60% of w hich were CK-7 negative) supports an appendiceal origin for these tumo rs. Our results also support an appendiceal (or colonic) source for an y CK-7-negative mucinous tumor involving the ovary or the peritoneum. Furthermore, our findings are in agreement with the assumption that mu cinous borderline-like tumors in the ovary associated with PP are not ovarian in origin but are often, if not always, metastatic from an app endiceal (or other) mucinous tumor. Copyright (C) 1997 by W.B. Saunder s Company.