RESUMO
Malignant transformation of ovarian mature benign teratomas is an uncommon complication which often occurs in the postmenopausal period. Clinical presentation is similar to that of benign ovarian cysts. The diagnosis of malignant transformation is often made per-operatively by the break of the capsule and the adhesions of the tumor or during histological examination. The diagnosis is based on the association between a mature teratoma and a non metastatic unitissular, carcinoma or sarcoma. All histological forms can be met, but squamous cell carcinoma accounts for 75% of all cases. We report the case of a 70-year-old woman who had a squamous cell carcinoma which developed on a teratoma of the ovary, for whom the disease was fatal. The survival rate for this kind of ovarian tumour is reduced, with 15 to 30% survival after 5 years, irrespective of stages and histological types. Although it is not easy to define the best requested therapy, surgery associated with polychemotherapy or radiotherapy is apparently the only way of improving the poor prognosis for these tumours