Malignant epithelial neoplasm usually occurs in postmenopausal women, with less than 10% of cases occurring in women under the age of 20. In patients below this age, the majority of ovarian tumors are of germ cell origin and malignant ovarian epithelial tumors are uncommon. We report US & CT imaging in a case of mucinous cystadenocarcinoma in a 17-year-old nullipara who complained of amenorrhea for 45 days and a palpable mass.