Cerebellar Extraventricular Neurocytoma with Spinal Seeding

Central neurocytomas are typically located in lateral or third ventricles. Here, we report a case of neurocytoma located in the middle cerebellar peduncle. A 36-year-old male patient presented with symptoms of ataxic gait and urinary incontinence for one month. Magnetic resonance imaging (MRI) of the brain revealed a slightly enhanced lesion on the left middle cerebellar peduncle with obstructive hydrocephalus. The preoperative diagnosis was a glial tumor and a subtotal surgical removal was performed. Following pathological studies, the final definitive diagnosis was made as central neurocytoma. Six months after surgery, the patient presented with low back pain and bilateral lower extremity weakness. Lumbar MRI studies revealed multiple intradural-extramedulary lesions. The patient was not operated for spinal lesions. He was treated with palliative radiotherapy in the metastatic spinal area. Cerebellar peduncle is an atypical location for a neurocytoma. Neurocytomas in atypical locations may behave more aggressively and make spinal seeding. According to neuroradiological and clinical presentation, these tumors may have been confused with other common cerebellar lesions. Pathological examination is needed for definitive diagnosis. Favorable prognosis is related to total tumor excision. (Marmara Medical Journal 2012;25:37-40)