Leiomyoma of the thyroid gland

Primary smooth muscle tumors of the thyroid gland are very rare neoplasms, leiomyosarcomas comprising the majority of these. Only three cases of prima ry leiomyoma have been reported to date, all of which have occurred in fema les of varying ages. We present the morphological, immunohistochemical and ultrastructural features of a fourth case of leiomyoma of the thyroid gland , occurring in a postmenopausal woman with a history of uterine leiomyomas.