e21569 Background: Pediatric atypical Spitz tumors and Spitz melanoma (AST/SM) are characterized by structural variants (rearrangements/truncations) of various kinase genes more commonly involving MAP3K8 and ALK. The clinical features associated with these genomic abnormalities have not been well characterized. Methods: We reviewed the clinical characteristics and outcomes of children and adolescents with AST/SM who were enrolled on our institutional comprehensive registry for melanocytic lesions MACMEL (Cancer 127:3825, 2021) and abstracted clinical and outcome data for patients with MAP3K8, ALK, and other less common genomic aberrations. Results: Table shows the characteristics and outcomes of patients with AST/SM who had MAP3K8, ALK, and other genomic aberrations. There were 49 patients of whom 21 had MAP3K8 rearrangements/ truncations (n = 11;22%) or ALK rearrangements (n = 10;20%). The remaining 28 patients had fusions involving ARAF (1), ROS1 (2), NTRK1 (3), ERBB2 (1) or rare mutations (ATM = 1) or copy number changes (n = 14) or no identifiable genomic abnormality (n = 6). Female sex was more common in all three groups (32 female and 17 male). The median age for the entire cohort was 7.5 years. Most lesions arose in the extremities (n = 32; 65%). About half had stage III disease. 40 patients underwent sentinel node biopsy (SLNB), 25 had at least one positive node (7/9 MAP3K8, 5/8 ALK, 13/23 other), Forty-four patients had FISH analysis for CDKN2A and homozygous loss was seen in 9/11 MAP3K8-rearranged, 2/6 ALK-rearranged, and 11/27 other tumors. No TERT promoter mutation was detected in any of the 45 tumors that were analyzed. Two patients experienced local recurrence, one with a MAP3K8-STX fusion and one with a FLOT2-ARAF fusion and activating RAC1 mutation. All patients are alive and currently disease free (median follow up of 2.33 years). There were no statistically significant associations between gene mutations and tumor site, gender, or stage. Conclusions: Approximately 40% of patients with AST/SM harbored ALK or MAP3K8 alterations in our pediatric melanoma registry. We found no significant association between the individual genes and any specific clinical features in this limited cohort.[Table: see text]