Palmini classification of focal cortical dysplasia published in 2004 was one of the leading classification systems used for focal cortical dysplasia, recently replaced by the Blumcke classification of focal cortical dysplasia.
Unfortunately, as is the case with many classification systems that have developed in parallel with numerous iterations and revisions, there is significant overlap between the various classifications systems with the same terminology used slightly differently.
The Palmini classification divides focal cortical dysplasia into three groups: mild malformation of cortical development (mild MCD), type I and type II.
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mild MCD
type I: with ectopically placed neurons in or adjacent to layer I
type II: with microscopic neuronal heterotopia outside layer I
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type I: architectural abnormalities with no dysmorphic neurons or balloon cells
type IA: isolated architectural abnormalities
type IB: architectural abnormalities, plus giant or immature, but not dysmorphic neurons
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type II: architectural abnormalities with dysmorphic
neurons (Taylor-type focal cortical dysplasia)type IIA: without balloon cells
type IIB: with balloon cells