Recurrent intestinal mucinous borderline tumors of the ovary: a report of 5 cases causing problems in diagnosis, including distinction from mucinous carcinoma.

Intestinal mucinous borderline tumors (IMBTs) of the ovary are generally associated with a highly favorable outcome and rarely recur. We describe 5 cases of IMBT initially treated by cystectomy or by salpingo-oophorectomy that was likely incomplete, with subsequent recurrences. Three cases were received in consultation, and in each of these, the clinical and intraoperative findings were worrisome for mucinous carcinoma, and diagnostic difficulty was encountered by the referring pathologist. The patient age ranged from 28 to 69 (median 53) yrs. All tumors were clinically Stage I at presentation; in at least 3 cases, extensive adhesiolysis was required during their removal. A pathologic diagnosis of IMBT was made in 4 cases; the remaining tumor was inadequately sampled (3 blocks from a 7.5-cm tumor showed predominantly benign to focally borderline mucinous epithelium). A total of 8 recurrences, all as IMBT, developed at mean follow-up of 26 (range, 6-102) mo; 6 of these occurred within ≤2 yr. In 4 cases, removal of recurrent tumor required an extensive operation because of bowel and/or vaginal involvement. Residual ovarian stroma was identified in all recurrences. There was no evidence of invasive mucinous carcinoma, pseudomyxoma peritonei, or a primary tumor elsewhere (including appendix) in any of the cases. Our findings indicate that patients with IMBTs who undergo cystectomy or oophorectomy requiring adhesiolysis are at increased risk of recurrence, which may occur early, be multiple, and potentially require extensive resection if sites such as bowel or vagina are involved. Recurrences of IMBT that develop in this setting likely represent regrowth of incompletely resected IMBT, or arise within residual ovarian tissue. This is the first detailed clinicopathologic study of such cases.