Spitz neoplasms are a heterogeneous group of melanocytic proliferations with diverse histopathologic features and variable biological behavior. Since Sophie Spitz’s 1948 description of “melanomas of childhood,” these lesions have been recognized as distinct from conventional melanoma, often showing cytologic atypia but typically following an indolent course. The spectrum includes Spitz nevi, atypical Spitz tumors (AST), and Spitz melanoma, with AST representing a diagnostic and prognostic gray zone marked by significant interobserver variability. Molecular profiling has advanced understanding of these tumors, revealing distinct alterations such as HRAS mutations and kinase fusions (ALK, ROS1, RET, NTRK1/3, BRAF, MET) compared with BRAF, NRAS, or NF1 mutations in conventional melanoma. Additional changes, including 9p21 deletions and TERT promoter mutations, influence biological behavior. Integrating molecular findings with morphology refines classification, improves diagnostic precision, and enhances risk stratification. This chapter highlights the genomic and morphologic spectrum of Spitz tumors and the evolving role of ancillary testing.