Inflammatory myofibroblastic tumor (IMT) is a rare entity. It is usually found in the lung and upper respiratory tract. Its location in the thyroid is exceedingly rare. Only seven cases of IMT of the thyroid were reported in the literature, mostly after the age of 50 years. The predominant histological pattern in all previously reported cases is that of marked plasma cell infiltrate. We report the detailed clinico-pathological and immunophenotypical features of a case of IMT of the thyroid in an 18-year-old girl with a family history of goiter. Our case is unique because it is the first and only known case of IMT of the thyroid in its alternative sclerosing subtype.