Focal cortical dysplasia type II Focal cortical dysplasia type IIa 2018-09-16T11:11:20Z A subtype of focal cortical dysplasia type II that is characterized by dysmorphic neurons, which present with a significantly enlarged cell body and nucleus, malorientation, abnormally distributed intracellular Nissl substance and cytoplasmic accumulation of neurofilament proteins. There are no balloon cells present (to be confirmed by immunohistochemistry). Discrimination of individual cortical layers is almost impossible (with the exception of Layer 1). Other cortical layer abnormalities are frequently encountered and should not be separately classified, including abnormal isocortical layer organization adjacent to the main lesion, as well as heterotopic neurons in Layer 1 or white matter.