Solitary fibrous tumor of the orbit: is it rare? Report of a case series and review of the literature.

PURPOSE: The real incidence of solitary fibrous tumor (SFT) of the orbit is unknown, but it seems that since it was first described in 1994, orbital SFT has been increasingly recognized. We believe that the orbital SFT is a relatively common tumor and that it should be considered in the differential diagnosis of any orbital tumor.

DESIGN

Interventional case series.

PARTICIPANTS

Four new cases of orbital SFT.

METHODS

Four patients affected by solitary fibrous tumor of the orbit are described. One patient experienced a recurrent SFT shortly after initial surgical excision performed elsewhere. Thirty-eight cases have been reported in the literature in 7 years.

RESULTS

The number of orbital SFTs reported has been increasing, reaching an average of more than five tumors reported per year. Since the first orbital SFT was described in 1994, 37 cases have been reported in the literature. We add four new cases in our series, including a recurrent tumor. A total of 42 cases have now been described, eight with recurrences. Malignant transformation occurred in one case.

CONCLUSIONS

We believe that before 1994, the diagnosis orbital SFT was confused with other benign orbital tumors, such as fibrous histiocytoma and hemangiopericytoma because of a lack of use of immunohistochemical techniques. This entity should now be considered relatively common and should be included in the differential diagnosis of orbital tumors in any age group. Local recurrences of SFT are possible and usually follow an incomplete initial excision. Recurrent tumors in the orbit have shown the tendency to infiltrate the surrounding tissues and the bone, rendering complete secondary excision more difficult. Recurrent orbital SFT also has the potential for malignant transformation. The treatment of choice of orbital SFT is complete surgical excision and careful follow-up. Considering the more aggressive course followed by recurrent tumor, correct diagnosis and management is essential.