Proton magnetic resonance spectroscopy of neurocytoma outside the ventricular region – case report and review of the literature

Central neurocytoma is classically considered as an intraventricular benign tumour, largely based on data from small retrospective series and single case reports. We report on a 16-year-old girl who suffered from a large parietooccipital tumour that was diagnosed histologically as central neurocytoma. The features of CT, MRI and proton MR spectroscopy studies are discussed. This is the first report on spectroscopic findings in a case of extraventricular neurocytoma. As well as elevated choline (Cho), the tumour spectrum showed strongly decreased N-acetylaspartate (NAA). NAA is assumed to be produced in mature neurons, and we therefore expected to find high amounts of NAA in this well-differentiated tumour, which was histologically composed of mature neuronal tissue. This observation leads to the conclusion that even the highly differentiated cells of neurocytomas are too immature to produce NAA.