Ectopic anterior cerebellum (ala lobule centralis).

In this case report we present an adolescent girl who was referred to our radiology department for assessment with advanced magnetic resonance (MR) imaging on suspicion of low-grade quadrigeminal cistern neoplasm on 1.5 Tesla MR examination. We were able to evaluate detailed cerebellar anatomy more clearly, and detected that the lesion was compatible with ectopic cerebellar tissue (a very rare developmental variation) on submillimetric 3-dimensional (3D) images from a 3 Tesla MR unit which has a 32-channel head coil. Our findings were further supported by diffusion tensor imaging which clearly indicated that the lesion was a part of the cerebellum. Furthermore, MR spectroscopic metabolite ratios were in accordance with the characteristics of normal neuronal tissue. As far we know there is no published report that contains similar findings to those of our patient. In conclusion, cranial MR images, if possible in 3D format (with very small isotropic voxels) should be obtained for the precise diagnosis of the lesions located in this region; in addition, the differential diagnostic list should be well known and advanced imaging techniques should be used when necessary.