Solitary fibrous tumor of the thyroid

Solitary fibrous tumor (SFT) is a rare spindle cell neoplasm mostly found in the pleural tissue but also described in other parenchymas. There are twenty four cases of thyroid SFT, all of them with similar histological appearance and immunohistochemical reaction pattern. We report the case of a thyroid tumor in a thirty year old man. The tumor was characterized by a proliferation of spindle cells arranged in a storiform and hemangiopericitoid pattern, without cell atypia and necrosis, and with low mitotic rate. The tumor showed a strong positive immunohistochemical reaction for CD-34 and bcl-2. There were no reactions for Desmin, Pancytokeratin and S-100. All of these features confirm the diagnosis of a thyroid SFT. It is important to know that this entity can arise in the thyroid gland to direct the analysis in a correct way.