ELECTRON MICROSCOPIC DIAGNOSTIC FEATURES OF MALIGNANT MELANOMA

Cases of three melanotic and two amelanotic malignant melanomas diagnosed in light microscopy were investigated in electron microscopy. When the findings were discussed it was seen that there were mostly electron dense melanosomes in tumor cells of melanotic melanomas and also a few undeveloped melanosomes premelanosomes in melanogenesis phase) could be recognized. Premelanosomes with definitely spheric, light matrix and a few developed melanosomes were found in amelanotic melanomas. Proliferation, polymorphism of premelanosomes and melanosomes were observed in tumor cells of both kinds of melanomas. In melanotic melanomas the melanocytes were in majority in amelanotic melanomas, but in amelanotic melanomas melanophages were dominant in view. In our opinion according to agressiveness of amelanotic melanomas premelanosomes were destructed and autolysed in early stages and development of melanosomes were destroyed so tumor tissue were observed in an amelanotic form. By the help of macromolecular and ultrastructural search some organospecific findings that were discussed in the study, made it possible to differ malignant melanotic melanomas from amelanotic melanomas definitely.

Keywords: melanotic, amelanotic melanoma, premelanosomes melanosomes, ultrastructure