Approximately 15 percent of epithelial ovarian tumors are tumors of LMP. Epithelial stratification, cellular atypia, mitotic activity, and abscence of ovarian stromal invasion set the histopathological criteria for diagnosis. Serous and mucinous tumors of LMP represent 80 to 95% of all cases. These tumors occur in patients at a younger age than those with invasive cancer and many times in fertile women who have not accomplished their family planning yet. Ovarian tumors of low malignant potential carry a favorable prognosis in comparison to invasive epithelial ovarian cancer. The recurrence rate after surgery for these tumors ranges from 10 percent to 30 percent, occurring as late as 10 or more years after presentation. The majority of patients (80-92 percent) with ovarian tumors of LMP present with stage I disease. Peritoneal implants display a range of histologic appearances, ranging from benign glands to those with features of invasive disease. Tumor markers such as CA-125 are not as useful in tumors of LMP as in invasive ovarian carcinoma. Elevated CA-125 are found only in patients with advanced serous tumors of LMP; thus, other markers such as transvaginal Doppler measurements of vascular resistant index has been suggested for possible differentiation between a benign and LMP ovarian tumors before surgery. Primary conservative surgery consisting of unilateral salpingo-oophorectomy is considered to be an appropriate treatment for young women with stage Ia ovarian tumors of LMP who wish to retain their fertility potential. Up to 70 percent of women who underwent conservative surgery subsequently conceive.(ABSTRACT TRUNCATED AT 250 WORDS)