Multiple CD34-Negative Orbital Solitary Fibrous Tumors in a Pediatric Patient

A 12-year-old Japanese male presented with a 2-month history of headache that was later on associated with diplopia, painless proptosis of the OS, and left ophthalmoplegia. Initial examination revealed a 7-mm OS protrusion, which worsened to 9 mm in less than a month. Preoperative visual acuity worsened from 1.0 to 0.2 with the development of left afferent pupillary defect. Left ocular motility was severely restricted in all directions. Magnetic resonance imaging showed two well-defined lesions adjacent to one another in the left orbit. The patient underwent surgical excision of the left orbital masses. Histopathology findings were consistent with solitary fibrous tumor of the orbit. Immunohistochemistry findings revealed CD34-negative but signal transducer and activator of transcription 6-positive for both specimens. The patient was monitored postoperatively and there was no recurrence of the tumor even after 6 months.