A rare case of primary neuroendocrine carcinoma of the central nervous system.

Primary neuroendocrine carcinoma (NEC) of the brain is an extremely rare presentation, with only a few previous case reports. We describe a primary NEC arising from the left parieto-occipital lobe. The 55-year-old patient presented with complaints of headache and dizziness for the preceding 7 months. Magnetic resonance imaging revealed a large ill-defined mass in the left parieto-occipital lobe, with possible differential diagnosis of meningioma. A craniotomy was performed, and a firm vascular tumor was removed. Histopathological examination revealed a large cell NEC. Immunohistochemistry was performed to exclude the possibility of an extracranial primary. Based on the immunohistochemical expression and absence of any extracranial tumor on positron emission tomography, the diagnosis of primary NEC of the brain was made. It is important to differentiate between primary and metastatic neuroendocrine tumors because they show a significant difference in prognosis and treatment.