Cystic Solitary Fibrous Tumor of the Orbit

ABSTRACT

Purpose@#To present a case of a cystic solitary fibrous tumor (SFT), the first report of its kind in Korea, along with a review of the literature of SFTs affecting the orbit.Case summary: A 71-year-old male was referred to our practice due to diplopia for 2 years and 6 months. On ophthalmologic examination, 10-mm proptosis and inferolateral globe displacement were observed in the left eye, and extraocular movements were limited in all directions of gaze. A facial computed tomography scan and magnetic resonance imaging showed a lobulated, well-enhanced mass in the superonasal extraconal space. The tumor appeared to be heterogeneous; cystic tissue was suspected. An excisional biopsy was performed through anterior orbitotomy to remove the mass (dimensions, 43 × 30 × 28 mm3). Histological examination showed the tumor to be composed of spindle cells in collagenous tissue. Immunohistochemical staining was positive for CD34, CD99, and orbital SFT with cystic changes. @*Conclusions@#SFT arising in the orbit is extremely rare but should be considered in the differential diagnosis of progressing unilateral proptosis, keeping in mind that this condition may be accompanied by cystic changes.