Ovarian mucinous borderline tumors of intestinal type without intraepithelial carcinoma: Are they still tumors of low malignant potential?

The purpose of this study was to clarify whether ovarian intestinal‐type mucinous borderline tumors without intraepithelial carcinoma should still be considered tumors of low malignant potential. Fifty‐five intestinal‐type mucinous borderline tumors without intraepithelial carcinoma in which a section had been taken for each 2 cm or less of the tumor's greatest diameter were selected. The International Federation of Gynecology and Obstetrics’ stage and follow‐up data of each case were examined. All 55 patients had stage I disease (including one with pseudomyxoma peritonei of superficial organizing type, according to Lee and Scully's classification). No patient had metastases or died from the tumor, although in one patient who underwent cystectomy, the disease recurred in the remaining ovary 5 years after surgery. However, the patient was alive and well after undergoing salpingo‐oophorectomy. The patient with pseudomyxoma peritonei had no recurrence and did not die from the tumor. These findings indicated that intestinal‐type mucinous borderline tumors, in which intraepithelial carcinoma has been ruled out with adequate histological sampling, are benign tumors, not tumors of low malignant potential. It is proposed here that these tumors should be designated as high‐grade mucinous adenoma. Unilateral salpingo‐oophorectomy is the recommended treatment because cystectomy alone may allow local recurrence in the remaining ovary.