Growing teratoma syndrome of ovary: avoiding a misdiagnosis of tumour recurrence.

Growing teratoma syndrome is characterized by conversion of immature gonadal germ cell tumour to a mature form, along with increase in size of the lesions. Being more frequently described in testicular germ cell tumours, growing teratoma syndrome in an ovarian tumour is uncommon. The exact cause of conversion and growth is unknown and is hypothesized to be induced by chemotherapy. On imaging, the diagnosis is suggested by the appearance of mature elements such as fat or calcium within these lesions and it is confirmed by normal serum markers despite the increase in its size. Knowledge of this entity is important, to avoid misdiagnosis as disease progression and continuing chemotherapy, as these lesions are refractory to chemotherapy. Though surgery is curative, they can also be safely followed-up in a majority of cases, with a favourable long term prognosis.