Abstract
We report the case of a 62-year-old woman with superficial spreading melanoma on her left thigh. The melanosomes in the cytoplasm of the tumor cells were studied electron microscopically. Although a small number of typical eumelanosomes were seen, there was a large number of altered melanosomes of spheroid shape and which contained vesicular, spiral microtubular and/or fragmented regular fibrillar matrices instead of parallel fibrillar structures. These melanosomes showed various amounts of diffuse granular melanin deposition. Based on recent advances in melanin chemistry and ultrastructural characteristics of eu- and pheo-melanosomes, these melanosomes were considered to be pheomelanosomes and/or mixed types of eu- and pheo-melanosomes. We speculate that the type and amount of melanin pigment in tumor cells might be responsible for variations in the macroscopic color of melanomas.
