The use of multiphoton laser tomography (MLT) for the in vivo differentiation and diagnosis of melanoma was studied by investigating 83 melanocytic skin lesions. Both sensitivity (up to 95%) and specificity (up to 97%) were high and six criteria for the evaluation of melanoma were identified. These comprised architectural disarray, pleomorphic cells, poorly defined keratinocyte borders, large intercellular distances and ascending melanocytes and dendritic cells. MLT is thus a promising tool for the diagnosis of melanoma (Dimitrow, E. et al. J Invest Dermatol 2009, 129(7): 1752).