Ultrastructural studies on the invasion of melanomas in initial lymphatics of human skin.

The way in which melanoma cells invade the initial lymphatics of the skin was investigated in this study. Samples of sixty melanomas were examined by transmission electron microscopy. Tumor cells invading lymph vessels were demonstrated in 20 specimens. In most cases the melanomas penetrated the subendothelial space as single cells. These fused with the endothelial cytoplasmic membrane and subsequently destroyed the endothelial wall.