The differential diagnosis of pPNET of the orbit includes other small blue round cell tumors which include rhabdomyosarcoma (Actin+, Vimentin+, Desmin +, S-100-ve), Ewing's sarcoma (PGP9.5+, MIC-2+), lymphoma (LCA+, CD45+/CD20+/CD3+), neuroblastoma (PGP9.5+, MIC-2 -ve) and metastatic retinoblastoma to orbit (NSE+, GFAP+).[2–4] Peripheral primitive neuroectodermal tumors are rare lesions that form part of the Ewing family of tumors, which includes osseous and extraosseous Ewing's sarcoma. This evidence concerns the gene CD99 and lymphoma.