RESUMO
Primary malignant parovarian epithelial tumors are extremely rare, with only 56 cases previously reported in the world literature. Most parovarian epithelial tumors are of paramesonephric (Mullerian) origin. In this article, we report the first case in the Korean literature of papillary serous cystadenoma of borderline malignancy from paramesonephric parovarian cyst. This case presented here is of particular interest since this neoplasm is rare. A 48-year-old female underwent a hysterectomy with bilateral adnexectomy and pelvic lymph node dissection for a cystic tumor of the right parovarian area. The tumor, measuring 13 cm in diameter, was apart from the ovaries, fallopian tubes and uterus. The cyst wall had well-developed smooth muscle layers. The cyst was lined with mildly atypical ciliated and non-ciliated low columnar cells compatible with those of paramesonephric origin. From the inner surface of the cyst several cauliflower-like structures projected into the lumen. They were of a predominantly papillary architecture covered by atypical epithelial cells with piling-up and occasional glandular growth. No destructive stromal invasion was identified.