Malignant transformation of ectopic thyroid tissue in the orbit: A rare case report

Ectopic thyroid tissue refers to the presence of thyroid tissue in locations other than normal anterior neck region. It is the most frequent type of thyroid dysgenesis. Lingual thyroid is the most common type accounting for 90% of the cases. The presence of thyroid tissue in orbit is extremely rare along with malignant transformation and the presence of normal thyroid gland. We report a very rare case of follicular carcinoma arising in the ectopic thyroid tissue in the left orbit along with normal thyroid gland. To the best of our knowledge, it is the first ever reported case of this type.