Peripheral primitive neuroectodermal tumor within the spinal epidural space

A case of an epidural spinal peripheral primitive neuroectodermal tumor (pPNET) in a 13-year-old girl is presented. The tumor was disseminated at the moment of diagnosis, thus only diagnostic oligobiopsy of the epidural mass was performed. Histologically the tumor was composed of small round blue cells. The neoplastic cells expressed MIC2 and features of neural differentiation on immunohistochemical staining (neuron-specific enolase, synaptophysin and NCAM positivity). Fluorescent in situ hybridization (FISH) analysis was performed for the final diagnosis and the translocation t(11;22)(q24;q12) was detected. The present case emphasizes the usefulness of FISH in differential diagnosis of tumors, especially when only routinely fixed material is available.