Anomalous alterations affecting microglia in the central nervous system of a fetus at 12 weeks of gestation: case report.

We report here on the first documented case of profound alterations specifically affecting the microglial population within the nervous system during the fetal period. This case, derived at gestational week 12, was one amongst a series of second trimester brains currently being investigated with respect to microglial colonization of the human fetal brain. No significant pathological alterations could be identified upon gross macroscopy or following microscopic analysis of serial brain sections stained with cresyl fast violet (Nissl). By contrast, sections stained immunohistochemically to detect MHC class II (CR3/43) and CD68 (PG-M1) antigens revealed a marked pathological change in the morp…