Septum pellucidum hamartomas in neurofibromatosis type 1

Septum pellucidum hamartomas have not been reported previously in neurofibr omatosis type 1 (NF1). In a retrospec tive study of 86 cases with NF1 we fo und three patients with septum pellucidum hamartomas (frequency = 3.4 %). T hese could be detected on especially fluid attenuated inversion recovery an d proton density-weighted images on MRI. With respect to proton spectroscop y in a patient, a low Cho level with a normal NAA peak was found, excluding a neoplasm. MR spectroscopy findings resulted in a very high NAA/Cho ratio (= 2.91), and a low Cho/Cr ratio (= 0.53) compared to a control group of 8 normal age-matched individuals. In this control group, mean NAA/Cho ratio was 1.86, and mean Cho/Cr ratio was 0.78.