A 52-year-old premenopausal African-American woman reports excessive bleeding from her vagina over the last 7 days. Imaging of the uterus shows a single bulky, oval mass originating deep to the endometrium. Biopsy reveals areas of necrosis and hemorrhage, with a high degree of cellular atypia and mitotic index. It is characterized as non-estrogen sensitive and appears to have arisen de novo. Which of the following is the best classification for such a tumor?
a. Endometrial carcinoma
e. Ovarian cyst