THE MORPHOLOGIC SPECTRUM OF OVARIAN METASTASES OF APPENDICEAL ADENOCARCINOMAS - A CLINICOPATHOLOGICAL AND IMMUNOHISTOCHEMICAL ANALYSIS OF TUMORS OFTEN MISINTERPRETED AS PRIMARY OVARIAN-TUMORS OR METASTATIC TUMORS FROM OTHER GASTROINTESTINAL SITES

Twenty cases of ovarian metastases derived from appendiceal adenocarci nomas were analyzed. The most common presentation was a pelvic mass. T he appendiceal and ovarian tumors were diagnosed concurrently in 15 ca ses; in the remaining five, the ovarian tumors were diagnosed before t he appendiceal tumor. The appendiceal adenocarcinomas demonstrated fou r morphologic patterns: 1) signet ring cell type, with or without glan dular or goblet cell differentiation (14 cases); 2) mixed signer ring cell and intestinal type (two cases); 3) intestinal type (two cases); and 4) typical colorectal type (two cases). The ovarian tumors were bi lateral in 16 cases and were histologically similar to the associated appendiceal tumor in each case. Ovarian metastases that demonstrate si gnet ring cell, glandular, and goblet cell differentiation mimic metas tases from gastric adenocarcinoma. Those that are derived from well-di fferentiated mucinous appendiceal adenocarcinomas mimic primary ovaria n mucinous tumors and metastases from the pancreas and biliary tract. Metastases of appendiceal adenocarcinomas of colorectal type simulate both metastatic colorectal carcinoma and primary ovarian endometrioid carcinomas. The appendiceal and ovarian tumors were immunophenotypical ly identical in each case. Approximately 50% of the appendiceal and ov arian tumors were positive for cytokeratin 7 (CK 7), and all were posi tive for cytokeratin 20 (CK 20). CK 20 positivity of the ovarian tumor s is consistent with gastrointestinal origin; CK 7 positivity does not confirm ovarian origin, because appendiceal carcinomas are positive i n 50% of cases. Metastatic appendiceal adenocarcinoma should be consid ered in the differential diagnosis of mucinous ovarian tumors with sig net ring cell, goblet cell, or intestinal type differentiation, especi ally when these tumors are associated with extraovarian disease and ar e bilateral.