Small Supratentorial, Extraaxial Primitive Neuroectodermal Tumor Causing Large Intracerebral Hematoma -Case Report-

A 16-year-old boy presented with an unusual case of a supratentorial, extraaxial small round blue cell tumor of the central nervous system, which was most likely a primitive neuroectodermal tumor (PNET). Preoperative computed tomography and magnetic resonance imaging showed a large multistage hematoma in the left central region. Intraoperatively, a small, superficial tumorous lesion was found between the sagittal sinus and a large cortical vein hidden by the hematoma. The histological diagnosis was PNET. This tumor is one of the most aggressive intracerebral tumors, not only in children, so treatment strategies must be early, profound, and interdisciplinary. This case represents an important example of atypical extraaxial appearance of this lesion, which should be considered in the differential diagnosis of cortical or subcortical hemorrhage, since complete resection of this lesion is critical for the successful treatment and outcome.