The Diagnosis and Treatment of Orbital Solitary Fibrous Tumor

Abstract

BackgroundSolitary fibrous tumor (SFT) is an uncommon spindle-cell tumor of mesenchymal origin, it commonly occurs within pleura, the occurrence of SFT in the orbit is very rare. The diagnosis of orbital SFT is challenging in clinical, and requires an integrated approach that includes specific clinical, histological, immunohistochemical, and even molecular findings.MethodsIn our retrospective study, we collected 13 patients with orbital SFT. All patients were diagnosed with orbital SFT by postoperative histopathological and immunohistochemical examination. Patient charts and medical records were reviewed for demographic information, relevant medical and family history, clinical presentation, radiological examination, histopathological and immunohistochemical examination, the treatment and prognosis.ResultsThis study included 7 males and 6 females. The age ranged from 11 to 78 years. 7 patients presented with predominant features of exophthalmos. 7 patients showed eyeball dislocation. 6 patients with motility disturbances. 9 patients had the palpable masses. 6 patients had the secondary lesions. On CT scan, there were 6 patients were located in the superomedial quadrant of the orbit, 3 patients were located in the inferomedial quadrant of the orbit. The morphology of lesions was solitary ovoid mass in 10 patients, and irregular mass in 3 patients. The CT value of the tumor was 22.8-64.4Hu, with the median of 45.9Hu. On MRI, 3 patients showed hypointense mixed signals on T1WI, 10 patients showed isointense mixed signal on T1WI. 3 patients showed hypointense mixed signals, 4 patients showed isointense mixed signals, 6 patients showed hyperintense signals on T2WI. There were 12 patients showed obviously enhancement, and we found patchy lesions which were no enhancement in the tumor. All patients were treated by surgery. Immunohistochemical analysis showed that the tumor cells exhibited diffuse immunoreactivity for CD34 and CD99 in all the patients. The lesions were positive for Bcl-2 in 11 patients. The lesions were positivity for Ki-67 <5% in one patient, 5%-10% in 10 patients, >10% in 2 patients. ConclusionsThe lesions are often outside the muscular cone, most commonly located at superomedial quadrant and inferomeddial quadrant of the orbit. The density of the lesions is uneven in most cases, the mean CT values of the tumors on CT scans are variable. The signal of lesions on orbital MRI is uncertainty, it is inheterogeneous enhancement, and the lamellar unenhanced regions can also be found in the lesion. The complete gross resection, and even more aggressive wide excision is preferred. Although the Ki-67 labelling index is very low, malignant forms with an increased propensity for local recurrence have been found. A longer follow-up is needed to determine the recurrence rate of the disease, and to identify the causes of recurrence.