Struma ovarii is a rare ovarian neoplasm. It is a monophyletic teratoma composed predominantly of thyroid tissue an account for less than 5% of mature teratomas. Struma ovarii has more than 50% of thyroid tissue while thyroid component is minimal in cystic struma ovarii. It is a challenging diagnosis for the pathologist if the Struma ovarii is either cystic or co-exists with any other cystic ovarian tumor. Extensive tissue sampling becomes mandatory in such cases to confirm the diagnosis and its co-existence with another cystic ovarian neoplasm.