Abstract Introduction Supratentorial primitive neuroectodermal tumors predominantly occur in children, and are rare in the adult population. Less than 100 cases of supratentorial primitive neuroectodermal tumor have been reported in adults internationally. Our case study reports this rare incident. Case presentation A 22-year-old Hispanic man presented with headaches, blurry vision, diplopia, intermittent vomiting, and grossly decreased vision. A magnetic resonance image showed a left posterior parietal heterogeneously enhancing mass measuring 4.2cm × 7.2cm × 7.0cm. After craniotomy for resection and decompression, the mass was histologically revealed to be a supratentorial primitive neuroectodermal tumor. Standardized immunohistochemical studies for this mass were carried out. Conclusion We have concluded that immunohistochemical and genetic workup should be included in the standardized pathological workup for primitive neuroectodermal tumors in order to provide more prognostic information. Based on our current literature review, we propose an immunohistochemical panel.