Orbital solitary fibrous tumor: Radiographic and histopathologic correlations

Objective: To correlate the clinicopathologic and radiographic features cha racteristic of orbital solitary fibrous tumor (SFT). Methods: The diagnostic features and clinical outcome of seven adults with orbital SFT are retrospectively outlined. Orbital imaging was performed by ultrasonography, computed tomography, or magnetic resonance imaging. Some c ases were imaged by multiple modalities. Histopathologic examination of eac h tumor specimen included standard light and immunohistochemical stains. Results: Heterogeneous internal composition was better appreciated on magne tic resonance imaging than on computed tomography. All cases undergoing mag netic resonance imaging showed T1 isointensity and T2 hypointensity relativ e to gray matter. Strong, generalized immunohistochemical reactivity to vim entin and CD34 validated the diagnosis of SFT and differentiated the specim ens from other spindle cell neoplasms. After complete tumor resection, our patients remain tumor free with postoperative intervals of 15 to 45 months. Conclusions: Solitary fibrous tumor has now been reported in 26 orbits. No physical finding is pathognomonic, but several imaging traits are highly ch aracteristic. Intralesional image heterogeneity and a predominantly low T2 signal intensity are distinctive of SFT. Complete tumor resection and immun ohistologic specimen evaluation are emphasized. Clinicians should consider the diagnosis of SFT when confronted with an adult patient having an orbita l soft tissue mass demonstrating the distinctive magnetic resonance imaging findings.