Primary leiomyosarcoma of the thyroid gland.

Sarcoma is a rare tumor of the thyroid gland, primary thyroid leiomyosarcoma (LMS) being even rarer. We present a case of LMS of the thyroid in a middle-aged female. Histopathologic examination in conjunction with immunohistochemistry helped to clinch the diagnosis. Knowledge of this entity is important to distinguish it from anaplastic thyroid carcinoma (ATC) and other sarcomas arising in the thyroid and adjacent soft tissue. The prognosis of thyroid LMS is dismal with an extremely poor survival rate.