Leptomeningeal changes over PMG cortex. a: The leptomeninges become adherent, thickened and vascular (arrow) as the cortex beneath them becomes abnormally festooned towards the left of the image. Mature brain (Haematoxylin and Eosin (H&E)). b: Fetus of 19 weeks: high power image shows reticulin stain to show the thickened leptomeninges over PMG cortex. The pial basement membrane is adherent and shows focal gaps with cells entering the leptomeninges from the subpial layer (short arrows). A vessel is seen crossing the pia between hypercellular leptomeninges and the cortex (long arrow) (reticulin).