ObjectiveIn adults, supratentorial primitive neuroectodermal tumor (sPNET) is a very rare undifferentiated embryoblastic neoplasm. Prognosis is worse in comparison to infratentorial medulloblastoma. Older age appears to be prognostically favorable. At present, 5-year survival rates remain below 50% in all age groups. Survival longer than 15 years in an adult has only been reported once so far.Case reportIn 1987, a 33-year-old-male patient presented with seizures following a six-month’s history of dizziness. CT- and MRI-scans revealed a right occipital tumor with moderate contrast enhancement. The tumor was completely removed. The original histological diagnosis was that of an undifferentiated sarcoma, malignant hemangioendothelioma, grade III. The patient was treated by CyVADIC chemotherapy and conventional radiation therapy (60 Gy). Admission for another reason in 2003 led to a re-evaluation of the original diagnosis. Microscopy revealed a malignant, highly cellular, poorly differentiated tumor with a desmoplastic component. Up to 20% of tumor nuclei were labeled for Ki-67. Almost all cells were stained for neuron specific enolase and NGF-Rp75, with neuronal and glial markers being present to a variable extent. According to these findings, the diagnosis was changed to a sPNET (WHO IV°). Other tumor entities were excluded by immunohistochemistry.ConclusionsAlthough the prognosis of sPNET is reported to be poor, a small fraction with a rather benign biological and clinical behavior exists. Parameters determining long-term-survival in sPNET are not yet known. Whenever possible, complete surgical resection should be attempted followed by postoperative radiotherapy. The value of chemotherapy is an issue of continuous investigation.