Primary intracranial peripheral primitive neuroectodermal tumor: lessons from an exceptionally rare neoplasm. Illustrative case.

BACKGROUND: The primary intracranial peripheral primitive neuroectodermal tumor (pPNET) is a lesion subtype within the Ewing sarcoma family of tumors. pPNETs are extremely uncommon pathologies, accounting for 0.03% of intracranial tumors and 1% to 2% of Ewing sarcoma cases. Given its histological aspect similar to other highly proliferative malignant neuroectodermal neoplasms, pPNET merits extensive workup for accurate diagnosis and treatment.

OBSERVATIONS: A 36-year-old male presented to the emergency department with a 1-year history of headaches in the right frontoparietal area, generalized tonic-clonic seizures, and a history of the resection of a tumor labeled as a meningioma 5 years before admission. He was neurologically intact. Brain magnetic resonance imaging revealed a heterogeneous focal lesion of 25 × 35 × 23 mm with a necrotic center and neoformative appearance in the right frontal cortex. The patient underwent multimodal treatment with gross-total resection, radiotherapy, and chemotherapy. Histopathological examination results supported the diagnosis of pPNET. At the 2-year follow-up, the patient had no new-onset symptoms, and brain imaging revealed absent signs of tumor recurrence.

LESSONS: The present case describes an extraordinary pPNET case, initially confounded as a clear cell meningioma. Managing pPNET requires thorough investigation, careful differentiation from similar neuroectodermal lesions, and multimodal treatment to improve the patient's prognosis.