Objective To investigate the clinical and magnetic resonance imaging (MRI) features of the tumors of septum pellucidum.

Methods We analyzed retrospectively the clinical data of 45 patients with the tumors of septum pellucidum confirmed by operation and pathology.

Results These tumors of septum pellucidum included 33 cases of central neurocytoma (CNC), 6 cases of astrocytoma, 2 cases of ependymoma, 2 cases of germ-cell tumor, 1 case of meningioma and 1 case of lymphoma. Headache accompanied with nausea and vomiting was the most common clinical manifestation. All the lesions were adhered to the septum pellucidum. MRI showed all the lesions were located in the septum pellucidum region, equal or short signal on T₁WI and equal or long signal on T₂WI, with even or uneven signals. The enhanced scans demonstrated different characteristics. CNC showed unevenly mild to moderate enhancement, and 19 cases of vascular flow void was observed. The low-grade astrocytomas showed mild enhancement in the parenchyma, while the high-grade astrocytomas showed obvious intensification or butterfly-like enhancement; no enhancement was found in subependymoma whereas significantly heterogeneous enhancement was observed in ependymoma; germ cell tumor, meningioma and lymphoma possessed significantly uniform enhancement. In addition, the magnetic resonance spectroscopy (MRS) of CNC and high-grade astrocytomas showed decreased NAA, increased Cho and increased rCBV of perfusion imaging. MRS with a significantly increased Cho peak, lack of NAA peak and Cr peak, but an Ala peak were observed in meningiomas, together with an obviously increased rCBV in perfusion imaging.

Conclusion The MRI of the tumors of septum pellucidum is characteristic and heterogeneous. Combined with clinical symptom and multiple sequence MRI, it is feasible to make a preliminary judgement of the pathology and to guide the clinical decision of the surgery and treatment plan.