Ultrastructure of spontaneously differentiated human malignant melanocytes cultured from primary tumors

Ultrastructural study of early subcultures and established lines of human malignant melanocytes derived from primary tumors showed that melanocytes passed through a phase of dedifferentiation during which they took on a fibroblast-like appearance; then they had a phase of spontaneous redifferentiation. The fibroblast-like cells were characterized by the presence of network-like organelles in their cytoplasm, and the melanocytes by melanosomes.