Solitary fibrous tumor of the orbit in a 1-year-old patient: a case report.

Solitary fibrous tumors (SFTs) are rare neoplasms of mesenchymal origin. While the mean age of presentation is 58 years old, we report the case of the youngest documented patient with an SFT of the orbit. A 13-month-old child was evaluated for eyelid asymmetry and then referred to the oculoplastic service. On examination, a soft tissue mass of the right inferomedial orbit was observed. MRI demonstrated a well-circumscribed, extraocular lesion in the inferomedial right orbit, potentially fibrous in nature. Excision was performed without complications. Pathologic examination demonstrated fibrous tissue proliferation with a staghorn vascular pattern, as well as benign fibrous cells with tapering nuclei and abundant pericellular reticulin. Immunohistochemistry (IHC) demonstrated that the cells stain diffusely positive for CD34 and vimentin. With the MRI findings, pathology, and IHC, the diagnosis was confirmed to be SFT. SFTs of the orbit, although rare, may occur in the pediatric population.