An electron microscope study of "Pacinian neurofibroma".

An electron microscope study has been made of the "Pacinian neurofibroma". Unlike the usual neurofibroma the "Pacinian neurofibroma" is characterized by a proliferation of the so-called perineurial cells. Groups of surface vesicles, the absence of mesoaxons and a fragmented basallamina differentiate these perineurial cells from Schwann cells. The formation of the perineurial cells can be traced continuously from small and wide submicroscopic cellbands and clubshaped thickenings to ribbonlike cell complexes as well as to tactile-like structures. The most developed complexes and structures are visible with the light microscope. These formations do not correspond with real tactile corpuscles, rather they can be considered as neoplastic structures of the perineurium.