{Reference Type}: Letter {Title}: Brachial plexus lipomatosis with perineurial pseudoonion bulb formation: Result of a mosaic PIK3CA mutation in the para-axial mesoderm state. {Author}: Ebner BA;Eschbacher KL;Jack MM;Dragana M;Spinner RJ;Giannini C; {Journal}: Brain Pathol {Volume}: 32 {Issue}: 4 {Year}: 07 2022 {Factor}: 7.611 {DOI}: 10.1111/bpa.13057 {Abstract}: