Primitive neuroectodermal tumor of the orbit in an adult - A case report and literature review

Objective: The authors describe the salient clinical, radiologic, and histo pathologic features of an orbital primitive neuroectodermal tumor in a 28-y ear-old man. This is an extremely rare tumor of the orbit, previously repor ted exclusively in children. Design: Case report. Intervention: Excisional biopsy of the tumor en bloc was performed. Main Outcome Measures: Histopathologic examination was performed by standar d techniques and immunohistochemical stains on formaldehyde-fixed, paraffin -embedded tumor tissues. Results: Histologic examination of the sections of the tumor showed small, blue, round cells with occasional Homer-Wright rosette formations. The tumo r cells stained positively with neuron-specific enolase and vimentin. Conclusions: This newly recognized, highly unusual peripheral primitive neu roectodermal tumor should be considered in the differential diagnosis of hy percellular, small, round cell tumor of the orbit in adults.