Electron microscopic study of nevic corpuscle.

An intradermal nevus, in which a number of nevic corpuscles were clearly observed, was studied, using the electron microscope. Nevic corpuscles contained laminated cells consisting of flattened cytoplasmic processes stretching across the corpuscles to form a complicated labyrinth. The perikaryon of these cells contained premelonosome-like dense bodies and other organelles including mitochondria, rough-surfaced endoplasmic reticulum, free ribosomes, and Golgi apparatus. Neither axons nor dendrites were found in these areas. From these observations, it was concluded that the nevic corpuscles were composed exclusively of nevus cells and could be clearly distinguished from Meissner corpuscles. This view would support the idea of a unitary origin of nevus cells. In addition, an isolated cilium found in a laminated cell is briefly discribed.