Summary

In this study, immunohistochemically Ki-67 (MIB-1) and p53 (D0-7) were applied to 22 nodular malignant melanomas (NMM), 25 Spitz nevi (SN) and eight atypical Spitz tumors (AST). In terms of p53, a significant difference was found between NMM and SN (p=0,0001), but the difference between NMM and AST was insignificant. Ki-67 index values were significant between NMM and AST (p=0,013), and also between NMM and SN (p=0,0001). The p53 values have significant difference between AST and SN (p=0,0002), but not the Ki-67 values. Immunohistochemical detection of Ki-67 and p53 are additional means to conventional histopathologic findings to differentiate between malignant melanoma, SN and AST. Specially considering AST cases, Ki-67 is more valuable than p53. We think, it is reasonable to label the cases as atypical Spitz tumor which have different aspects from Spitz nevus but also have no sufficent findings to be diagnosed as conventional malignant melanoma. It is reasonable to suggest reexcision and clinical follow-up for these cases.