Solitary fibrous tumor of the thyroid gland.

We report a case of solitary fibrous tumor of the thyroid gland in a 51-year-old man with pre-existing right recurrent laryngeal nerve paralysis from a congenital tracheoesophageal fistula repair as an infant. The left thyroid lobe was enlarged and soft. Fine needle aspiration biopsy via ultrasound guidance demonstrated a hypercellular aspirate composed of spindle cells with bland nuclear morphology. Given this histomorphology and immunohistochemical profile, the diagnosis of solitary fibrous tumor was considered and confirmed following left thyroid lobectomy.