Résumé : The distribution of the messenger RNA coding for the recently cloned growth factor pleiotrophin (HB-GAM) was studied in human benign meningiomas using in situ hybridization histochemistry and oligonucleotide probes. Pleiotrophin mRNA was selectively found in the meningothelial cells whilst not detected in the fibroblastic cells, blood vessels and collagen bundles of the meningiomas.