[Ultrastructure of pigmented skin nevi].

Nevus cells are biologically significant because they are associated with epidermal melanocytes, while their clinical malignant melanomas. Apart from many other ultrastructural features their mutual characteristic is that they are exceptionally diverged. The main feature distinguishing nevus cells from melanocytes is the presence of big binuclear cells as well as frequent occurrence of grouped melanosomes in their cytoplasm.