Bipolar cellular morphology of malignant melanoma in unstained human melanoma skin tissue.

Microstructures of unstained human melanoma skin tissues have been examined by multimodal nonlinear optical microscopy. The polarized shape of the individual melanoma cell can be readily recognized-a phenotype that has been identified in laboratory cultures as characteristic of proliferating melanocytes but has not been demonstrated in clinical instances. The results thus provide snapshots of invading melanoma cells in their native environment and suggest a practical means of connecting in vitro laboratory studies to in vivo processes.