Fig. 2

Algorithm for requesting complementary techniques to determine atypical melanocytic tumor type and category. This information for the “other” cases is not presented because of their heterogeneity. Blue, our case diagnoses according to the algorithm. Purple, our case outcomes based on available information. Note: OMTs (other melanocytic tumors), including acral and mucosal lesions common in Asia and Africa, were excluded from the diagnostic algorithm due to the limited number of cases. This exclusion may affect the generalizability of our findings. SRT Spitz–Reed tumor, ATNT atypical thick nevoid tumor, AThinT atypical thin tumor, IHC immunohistochemistry, NC noncontributory, FISH fluorescence in situ hybridization, CGH comparative genomic hybridization, +  positive, – negative, A atypical, DA doubtful atypical, LN⁺ lymph-node metastases, M⁺ organ metastases, RMS remission.