Series of "private" photographs taken of patients over many years can greatly aid in following the course of development of malignant melanomas. In one case of superficial spreading melanoma, the pigmented lesion displayed spread around the entire circumference, maintaining its round shape throughout its course. The other tumors enlarged by focused spreading at various points along the border, changing in shape over several years of development. The temporary appearacne of two closely adjacent pigmented lesions frequently occurred during the early development of malignant melanomas, followed by fusion after progressive spread. Lentigo maligna melanoma showed the greatest continuous alteration of shape. Different tumor types observed over similar periods of time showed different dynamics of growth with reference to shape (horizontal spreading growth) and depth to invasion (vertical growth).