Thyroid type papillary carcinoma arising in a mature teratoma

Struma ovary is a monodermal ovarian teratoma which contains mature thyroid tissue. We present an unusual case of papillary carcinoma arising in struma ovarii. A 52 year old post menopausal lady presented with a large right adnexal mass preoperatively diagnosed as a dermoid cyst. She underwent staging laparotomy and the histopatholgy report showed follicular variant of papillary carcinoma thyroid arising in a mature teratoma. She subsequently underwent total thyroidectomy to enable follow up with serum thyroglobulin and iodine scan. On follow up there is no evidence of disease recurrence.