ABSTRACT
Germ cell tumors constitute approximately 20%- 30% of all ovarian tumors.Mature cystic teratomas account for 95% of germ cell tumors. Malignant transformation in a mature cystic teratoma of the ovary is a rare event, developing in 1 to 2 % of cases with squamous cell carcinoma being the most common malignant transformation(75%). We report a case of malignant transformation in mature cystic teratoma of the ovary in a 45 year old multiparous woman who had presented with pain abdomen for last two months. Pain was not releaved by symptomatic measures and therefore investigations were carried out, Radiological investigations revealed bilateral ovarian teratoma. During laprotomy a large cystic mass was seen arising from the left ovary that was adherant to the large gut. Right ovary was also found to be enlarged. Final histological diagnosis of bilateral cystic teratoma of ovaries with malignant squamous cell carcinoma arising in left ovarian teratoma was made.