[Orbital solitary fibrous tumor: a clinicopathologic analysis]

To study clinicopathologic features, histologic characteristics, differential diagnosis and the treatment of orbital solitary fibrous tumor (SFT).

Clinical, radiographic and pathologic findings of 6 cases of SFT were retrospectively analyzed. Immunohistochemistry were performed on selected samples.

Four patients were males and 2 were females. Patients age ranged from 19- to 57-years-old. The location of the tumor was in the muscle cone (case 1 and case 5), medial (case 3), lateral (case 4), superior (case 2) and inferolateral (case 6) portion of the orbit, respectively. The presenting symptom was proptosis in 3 cases and was mass of subconjunctival or orbit margin in other 3 cases. Image examination: SFT appeared as a round (case 6 showed irregular) and well-circumscribed parenchymatous mass that could be homogenously enhanced by contrast. Histologically, SFT displayed as a mass of spindle cells in an irregular arrangement Sometime, tumor cells could be storiform or sarciniform. Mitotic figures were infrequent and usually there were 0 to 3 mitotic figures per 10 high-power fields. Hyalinization and staghornform blood vessels were frequently observed. SFT was immunoreactive for markers such as Vim, CD34 and CD99. Two cases were recurred.

SFT is a rare orbital tumor and could be confused with other types of orbital tumors. This tumor can be diagnosed by pathological and immunocytochemical studies, these characteristics can be used to differentiate it from other types of orbital tumors.