Peripheral primitive neuroectodermal tumor of the orbit. Review

Peripheral primitive neuroectodermal tumors (pPNETs) are a group of soft tissue tumors of neuroepithelial origin, that arise outside the central and sympathetic nervous system. Orbital location is infrequent, to the best of our knowledge only sixteen cases have been reported in the literature. With this article we would like to report the demographics and clinical characteristics, diagnostic features, differential diagnosis, prognosis and therapeutic options of primary orbital peripheral primitive neuroectodermal tumor, based on our patients and on the cases reported in the literature up to now. Differential diagnosis should be made with other small round cells tumors, immunohistochemical and ultrastructural techniques are essential for this purpose. Although bone invasion and extraorbital extension are possible, systemic metastases are uncommon in the cases of orbital pPNETs. Surgery has been the initial treatment in most cases; chemotherapy +/- radiotherapy is considered the best additional treatment. The orbital variety seems to be less aggressive than other forms of pPNETs since most of the patients reported were alive after the follow up period (at least 6 months).