Mucinous tumors of the ovary - A clinicopathologic study of 196 borderlinetumors (of intestinal type) and carcinomas, including an evaluation of 11 cases with 'pseudomyxoma peritonei'

Mucinous ovarian neoplasms other than cystadenomas and adenofibromas have b een classified as either borderline tumors or carcinomas for many years. Bo rderline tumors have been subdivided more recently into endocervical-like ( mullerian) and intestinal forms. Such a distinction is rarely made in the m ucinous carcinoma category. We did not encounter a pure endocervical-like c arcinoma in the present series. Criteria for distinguishing an intestinal-t ype mucinous borderline tumor from a mucinous carcinoma have been controver sial. In this study of 164 mucinous borderline tumors of intestinal type an d 32 mucinous carcinomas, the former were further subdivided into 74 cases with epithelial atypia only and 90 with focal intraepithelial carcinoma. Of the 67 stage I tumors in the borderline (with atypia) category, all 49 wit h follow-up data were clinically benign; in the seven cases that had been d esignated stage III, the intraoperative appearance was that of "pseudomyxom a peritonei," which was fatal in four cases. Most of these tumors, however, were probably metastatic to the ovary rather than truly primary borderline tumors, although failure to examine the appendix in six cases compromised their interpretation. All 90 mucinous borderline tumors that had foci of in traepithelial carcinoma were recorded as stage I, but two of the 69 patient s with follow-up data (3%) had fatal recurrences. Both of these tumors were incompletely staged, however, and one had ruptured intraoperatively. Thirt y-two invasive carcinomas were subdivided into 12 expansile and 20 infiltra tive subtypes; within the latter category seven tumors were only microinvas ive. All 12 carcinomas with only expansile invasion were stage I; none of t he 10 with follow-up data recurred. All seven microinvasive infiltrative ca rcinomas were stage I; none of the five with follow-up data recurred. One o f five patients with stage I infiltrative carcinomas that were more than mi croinvasive and were adequately followed had a fatal recurrence, but stagin g had been incomplete in that case. Seven of the remaining eight infiltrati ve carcinomas were higher than stage I; five of the six (83%) with follow-u p data persisted or recurred and were fatal. Considering all stages, increa sing tumor grade in the carcinoma category correlated with an unfavorable o utcome. However, grade did not influence prognosis in stage I carcinomas. A mong 13 stage I cases in all categories with either preoperative or intraop erative tumor rupture and followup data, one recurred, a tumor in the borde rline with intraepithelial carcinoma category. "Pseudomyxoma peritonei" is an ill-defined term and should not be used as a pathologic diagnosis. The p resence of mucin in the abdominal cavity requires careful histologic evalua tion to characterize it for prognostic purposes. Adequate and sometimes ext ensive sampling of mucinous ovarian tumors, the appendix and the peritoneum in cases of "pseudomyxoma peritonei" is necessary to achieve an accurate d iagnosis and prognosis.