Palmini classification of focal cortical dysplasia

Palmini classification of focal cortical dysplasia published in 2004 was one of the leading classification systems used for focal cortical dysplasia, recently replaced by a newer classification; 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.

• mild MCD
  • type I: with ectopically placed neurons in or adjacent to layer I
  • type II: with microscopic neuronal heterotopia outside layer I
    ​
• 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
     
• type II: architectural abnormalities with dysmorphic
  neurons  (Taylor-type focal cortical dysplasia)
  • type IIA: without balloon cells
  • type IIB: with balloon cells