Malformations of cortical development of the human brain: a pictorial essay

During development in utero of the human brain, an error in one or more of the orderly processes of neuroblast proliferation and differentiation, neuroblast migration and cortical organization may result in disordered neocortical development. Nowadays, the consequent malformations of the cerebral cortex and associated structures are detectable on pre- and postnatal examination with growing frequency, thanks to the evolution of modern imaging modalities. In particular, magnetic resonance imaging (MRI), due to its excellent contrast differentiation and multiplanar capabilities as well as the development of even newer techniques, such as diffusion tensor imaging and spectroscopy, has surpassed all other forms of imaging for the thorough exploration and analysis of congenital anomalies of the central nervous system. These malformations comprise a heterogeneous group of conditions in terms of both the timing and etiology of the developmental aberration as well as the resulting morphological phenotype, including epilepsy, developmental delay/intellectual disability and focal neurological deficits. This study briefly presents some typical examples of congenital malformations of cortical development of the human brain that are encountered in practice. It is our belief that familiarity with the MRI presentations of these conditions can be of considerable value for adequate disease management and genetic counseling.