Teratomas of the neck in adults.

True teratomas of the neck in adults are unusual neoplasms. Their clinicopathologic aspects are distinctly different from the counterpart tumor of the neonate and infant. While the latter is almost always a benign tumor, adult teratomas are both histologically and clinically malignant neoplasms. To our knowledge, we report the tenth case of a teratoma of the neck in an adult.